ML20079N123

Cape Fear Studies Interpretive Rept for 1985

ML20079N123
Person / Time
Site:	Brunswick
Issue date:	12/31/1985
From:	CAROLINA POWER & LIGHT CO.
To:
References
RTR-NUREG-1437 AR, NUDOCS 9111110087
Download: ML20079N123 (100)

Text

< _

4p;  ;.g y , . - W ~f 9 . ,1 e N+ ': [-

i>}

s - a$ ger #"

p ts ,.

A:,c;p'w;,'.y,:<-

p -ji e

% ij:{yl@ 'p  :

l- fl$Ih, ," '

we

. . . a v .w s MmA.S.

Ej?C$$ \@i. ~,

Brunswick Steam Electric Plant t+ee Lz Cape Fear Studies W

g;;+%g.

. w

([p#L;- >

Interpretive Report

$m$ ny

$ <-_4 R"

GiW:p,  :

August 1985 lf$

7,.,, .

[ ); j % a i

$h0fy,' ' .

Qf? Q

• Nl qw;-;.

-\'%Q f:Jy {f!!4 , s t-

%x p

f~

g;leo

':. > L bhh ,'

mt ,

f IfI' a

fC. ,

g?n s s jn k'As%db W9 .a  :-

q$.p):ly  % n 1

%_ sz.4 I. t .

qsa h;"

~ft

,yi bk?/ e-Q:@ <

l(("E.B CareHas Power & Ught Company g?,

p.'

G i

u 9111110087 851231 PDR NUREQ ~ #

4 a437 C PDR < A --

a e

I I

I BRUNSWICK STEAM ELECTRIC PLANT l Q CAPE FEAR STUDIES b

INTERPRETIVE REPORT I

I August 1935 1

I I

3 Carolina Power & Light Company

< g New Hill, North Carolina I

I e

I.

This copy of this report is not a controlled document as detailed in Er,vironmental Services Section Procedures. Any changes made to the original of this report subsequent to the date of issuanc<3 can ,

be obtained feca: 5

'N Manager '

Environmental Services section Carolina Power & Light Company

{

Shearon Harris Energy & Environmental Center  !

Route 1, Box 327 New Hii1, North Carolina 27562 I Eti.>

I .

4

~

I i l

I m

l l

Table of Contents r

I L

Page L List of Tab 1es................................................ ... ii List of Figures................................................... iv Executive Summary................................................. vi Metric-English Conversion Tab 1e................................... x 1.0 INTR 000CT10N.............................................. 1 Objectives ............................................... 3 The Brunswick Steam Electric P1 ant........................ 4 Permit Requirements....................................... 5 The Cape Fear Estuary and its Biological 1 Components................................................ 6 2.0 WATER QUALITY............................................. 7 3.0 RIVER LARVAL FISH......................................... 9 4.0 HIGH MARSH.,.............................................. 12 5.0 NEKT0N.................................................... 16 6.0 ENTRAINMENT............................................... 18 7.0 IMP!NGEMENT..................... ....................... 21 Juvenile and Adult Impingement............................ 21 Larval and Postlarval Impingement......................... 23 l Impingment -Combined Effects.............................. 24 8.0 FISH O! VERSION STRUCTURE.................................. 25 9.0 SURVIVAL STU0lES.......................................... 26 10.0

SUMMARY

................................................... 28 11.0 SUPPORTING 00CUMENTS...................................... 32 l .

i

s list of Tables l

4 Table Pace 1 A summary of the BSEP biological studies program............ 44 2 Annual mean density and the percenicge of the total mean density for the eight most abundai ,; species collected in the river larval fish program, 1974-1984....... 45 3 Results of time-series analysis for river larval fish

'a data, 1977-1984, indicating significant changes in g density along with amount of variance explained by the model by station group.................................. 46 4 Results of analysis of variance comparing 1984 1 river larval fish density dat from Dutchman Creek and Walden Creek............................................ 47 5 Salinity preference of selected species collected by trawl and seine in the high marsh study from 1981 through 1984........................................... 48 6 Catch-per-unit-effort by creek system for 12 selected species collected by trawl and seine in the high marsh study during 1984............................ 49 7 Mean log catch-per-unit-effort of total organisms collectebbytrawlinBaldheadCreekandWaldenCreek in the high marsh study during 1984......................... 50 8 Results of time-series analys,a of high marsh data 1 by creek showing significant trends in abundance from 1981 through 1984...................................... 51 9 Standing crop estimates of selected or9anisms collected in North River Estuary, Jarrett Bay, and in the Cape Fear Estuary, North Carolina, from 1977 through 1984...................................... 52 10 Peak seasonal recruitment of selected species collected by trawls and seines in the high marsh I study from 1981 through 1984................................ 53 11 Annual catch-per-unit-effort (CPUE) by station of the dcminant commercial species collected in the nekton s t u d y d u r i n g 19 8 4 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 12 Reduction in entrainment mean density for selected species for three special study periods..................... 54 ii

Qst of Tables (continuedJ e

Table Pace 13 Comparative reductions in entrainment of total

{ organisms due to flow minimization.......................... 55 14 Percent composition of entrainment density from 1975 through 1984................................................ 56 15 Estimated survival of juvenile and adult organisms impinged during 1984........................................ 57 16 Overall percent survival and number of larval organisms impinged and returned alive to the -

Cape Fear Estuary........................................... 58 17 Results of analysis of variance and Duncan's multiple range test for selected nekton species comparing stations inside and outside the BSEP diversion structure during 1984............................. 59 lB 18 Survival percentages for organisms collected during fast and slow screen operation at the BSEP during 1984 and 1985............................................... 60 19 Survival percentages for control oraanisms collected for survival studies at BSEP during 1984 and 1985........... 61 Comparison of percentages of reduction of larvae l 20 cropped by the BSEP as a result of fine-mesh screens and flow minimization....................................... 62 I

I I

iii

list of Figures I.

Figure Page I 1 Location of sampling stations for the Brunswick q Steam Electric Plant biological monitoring program.......... 63 2 Location of diversion structure, sluiceways, and return basin at the Brunswick Steam Electric Plant.......... 64 3 Bottom salinity values from selected river and creek stations in the Cape Fear Estuary, September 1983-December 1984............................................... 65 4 Bottom temperatur. values from selected river and creek stations in the Cape Fear Estuary, September 1983-December 1984.................................. ......... 66 5 Results of time-series analysis of total larval /

I postlarval organisms collected in Walden Creek, 1977-1984, showing the seasonal occurrence of organisms..... 67 Results of time-series analysis of larval /

I 6 postlarval anchovy collected in Walden Creek, 1977-1984, demonstrating the regular periods of occurrence with yearly variations........................ 68 I 7 Cumulative length-frequer~y analysis of postlarval croaker collected from upriver and iI downriver larval fish stations on March 9, 1983, indicating a larger percentage of smaller fish downriver................................................... 69 8 Results of time-series analysis for total organisms collected in nekten small trawls at Statior.:, 1, 4, 7, and 8 combined for 1979 through I 1984........................ 70 9 Results of time-series analysis for brown shrimp collected in nekton small trawls at Stations 1, 4, 7, and 8 combined for 1979 through 1984........................ 71 10 Results of time-series analysis for juvenile / adult spot I collected in nekton small trawls at Stations 1, 4, 7, and 8 combined for 1979 through 1984......................., 72

.g 11 Time line depicting initiation dates of the Brunswick

.g Steam Electric Plant modifications and maximum flow /

unit from June 1981 through April 1985...................... 73 I 12 Entrainment day / night mean densities for total fish, September 1974 through August 1985.......................... 74

'I iv I

L List of Figures (continued)

Figure Page_

13 A comparison of entrainment densities of total fish

[ before and after installation of fine-mesh screens.......... 75 14 Ratio of entrainment densities to river larval fish Station 25 densities of total fish, September 1976 through Au5ust 1984......................................... 76 15 Cumulative length distributions of bay anchovy 1 impinged at the Brunswick Steam Electric Plant l in 1981 ard 1984............................................ 77 16 Cumulative length distributions of menhaden impinged at the Brunswick Steam Electric Plant I in 1981 and 1984............................................ 78 i

17 Cumulative length distributions of spot l impinged at the Brunswick Steam Electric Plant l in 1981 and 1984............................................ 79 l 18 Cumulative length distributions of croaker impinged at the Brunswick Steam Electric Plant in 1981 and 1984............................................ 80 19 Length-frequency plots of bay anchovy impinged at the Brunswick Steam Electric Plant during 1984 compared to 1981....................................... 81 1 20 Results of time-series analysis for juvenile / adult spot collected by the nekton trawl at the river stations 1979-1984 and the intake stations 1981-1984................................................... 82 l 21 Results of time-series analysis for juvenile / adult croaker collected by the nekton trawl at the river stations 1979-1984 and the intake stations 1981-1984................................................... 83 22 Results of time-series analysis for juvenile / adult menhaden collected by the nekton trawl at the river stations and the intake stations, 1981-1984................. 84 23 Cumulative length-frequency analysis of spot collected by the nekton trawl outside and inside the diversion structure during 1984......................... 85 l 24 Cumulative length-frequency analysis of croaker collected by the nekton trawl 'utside and inside the diversion structure during 1984......................... 86 l

v

Executive Summary r Brunswick Steam Electric Plant L

Cape Fear Studies Interpretive Report L

The current National Pollutant Discharge Elimination System permit for the Brunswick Steam Electric Plant requires that "A biological moni-toring program shall be designed and implemented which will provide suffi-cient information to allow for a continuing assessment of the impact of the BSEP on the Cape Fear Estuary with particular emphasis on the marine fisheries. This program shall at least include impingement studies (in.

cluding organisms returned), entrainment studies, nekton studies, and g marsh recruitment studies. Data shall be reported on an annual basis and P shall include an assessment of the effectiveness of the diversion fence, flow minimization, and fine-mesh screens in minimizing impingement and entrainment along with an interpretive summary report."

For the last 11 years, the plant has been withdrawing water from the estuary. During thie ll-year period, extensive environmental studies have been conducted to d ' ine if the plant's withdrawal of water from the estuary has been adversely affecting fish and shellfish populations. The results of these studies indicate that the operation of the plant has not

, adversely affected the fisheries in the estuary in any measurable way.

I The biological studies show:

1. The estuary is a stratified, two-layered estuarine system with a typical freshwater / salt-wedge interface. This is carticularly true above the river constriction at Sunny Point where a salin-ity gradient exists which is modified by freshwater inflow and tidal flows, i

2. There is a seasonal movement into, an associated residence time, and a movement out of the estuary by ocean-spawned species of fish and shellfish. There is no evidence that this mechanism has been impacted by the operation of the plant.

vi I . . . . . .

s r 3. The abundance, size, distribution, and dominance of larvae in the estuary have not changed in the past ten years.

I L 4. The discrete depth sampling program verifies that vertical dis-tributions and diel (day / night) behavior of larvae are the same as reported in past studies and that mean densities calculated l from surf ace and bottom samples are not statistically dif ferent than mecns calculated from discrete depth sampling. Therefore, the reduction in the scope of the larval fish program in 1980 did not reduce our ability to detect changes in larval / post-larval populations.

5. The similarity in concentrations of larvae and postlarvae in I Out:hman Creek (a control creek not influenced by the plant) and Walden Creek (located near the plant) indicates that there has been no depletion of larvae in Walden Creek despite its close proximity to the intake canal. In fact, the two creeks are not significantly different in their nursery functions.

6. The marsh study indicates that the primary nursery areas are still being used to capacity today and that recruitment, sea-sonality, and abundances of postlarvae and juveniles in those areas are uninterrupted by the operation of the plant.

I 7. The abundances of nektonic (free-swimming) organisms have not j significantly changed. The distribution of these organisms is 1 related to spatial and environmental variables and not to the operation of the plant.

I

, 8. Dominant species and the seasonal abundances of entrained organ-isms mimics those of the river larval fish program.

9. Special studies show that entrainment is reduced by about 82%

when fine-mesh screens are compared to 9.4-mm screens. Flow minimization results in a 26.5% to 47.4% entrainment reduction, vii o __

I yielding a calculated reduction of 90% when both measures are employed during the cooler portion of the year. This period corresponds to a time when a preponderance of commercially im.

I portant species are entrained, thus giving an additive reduction during this critical period.

10. Though greatly reduced, some entrainment of larvae still occurs, but the populations in the estuarine nurseries have not been af-fected.

I 11. Impingement of large organisms has been reduced due to the fish diversion structure. The construction and operation of the fish diversion structure prevent the movement of larger organisms into the intake canal with a resultant 67% decrease in weight of

'I impinged organisms.

12. The use of fine mesh on the traveling screens reduced the size of organisms impinged but the number of organisms impinged in-creased.

13. Because of the diversion structure, juvenile and adult impinge-ment losses now occur' from a greatly reduced population of available organisms. Reduction in the cropping rate of these larger individuals is especially important since, having sur-vived life stages with high natural mortality rates, they are I more likely to contribute to the species propagation.

14. Survival ' tudies indicate that there is a substantial return of live organisms to the estuary. Menhaden, a fragile species, show a low percent survival. The survival values are approxi-mately 90% for blue crabs and shrimp and 35% for spot and croaker.

The findings of these studies show that the mechanisms that operated within the estuary to deliver larvae spawned offshore to primary nursery areas are unaffected. The species composition, abundance, size, and I

viii

seasonality of the organisms are unchang... Additionally, the intake mod-ifications have substantially reduced impingement of larger organisms and increased survival of the smaller organisms that are impinged.

In conclusion, CP&L believes that the continued operation of the BSEP with the present modifications shows no measurable adverse impact on the Cape Fear Estuaiy.

,I I

I  ;

• I

• I l 1 I

l i

lI LI b

I I

ix

Metric-English Conversion Tau I

' Length 1 micron (um) = 4.0 x 10-5 inch

. 1 millimeter (mm) = 1000 um = 0.04 inch I centimeter (cm) = 10 nim = 0.4 inch 1 meter (m) = 100 cm = 3.28 feet i kilometer (km) = 1000 m = 0.62 mile I Area i 1 square meter (m2 ) = 10.76 square feet I hectare - 10,000 m2 = 2.47 acres Weight 1 milligram (ug) 3.5 x 10-5 ounce 1 gram (g) = 1000 mg = 0.035 ounce 1 kilogram (kg) = 1000 g 2.2 pounds i Volume i 1 milliliter (ml) = 0.034 fluid ounce ,

1 liter = 1000 ml = 0.26 gallon I 1 cubic meter per second (cms) = 35.7 cubic feet - second (cfs)

Temperature Degrees centigrade (*C) = 5/9 (*F - 32)

X

Brunswick Steam Electric Plant r Cape fear River Studies Interpretive Report

1.0 INTRODUCTION

Since the early developmental stages of Carolina Power & Light

( Company's (CP&L) Brunswick Steam Electric Plant * (BSEP), both federal and state agencies have reviewed the design and operation of the plant through the National Pollutant Discharge Elimination System (NPDES) permitting process. The agencies included:

U.S. Atomic Energy Commission (now the Nuclear Regulatory Commission)

U.S. Environmental Protection Agency National Marine Fisheries Service U.S. Fish and Wildlife Service North Carolina Division of Environmental Management North Carolina Division of Marine Fisheries Af ter more than a decade of biological monitoring, culminating in the 20-volume Cape Fear Studies report, and with agency review and scrutiny, an NPDES operating permit was reissued in January 1981. Regarding withdrawal of water from the Cape Fear Estuary (CFE), the stipulations of the permit were that:

I 1. A permanent fish diversion structure be built and main-tained at the mouth of the intake canal.

g

2. Fine-mesh screens be inst led on two cf ne four traveling 3 -

screen assemblies on each unit.

3. Seasonal reductions in water flow be instituted.

• Throughout this report, the Brunswick Steam Electric Plant will be referred to as "the plant "

L r As part of the current permit renewal process, this interpretive f

L report examines the effectiveness of these mitigative measures.

This report also examinos the overall ef fects of the plant's opera-tion with respect to the fish and shellfish populations of the Cape Fear '

Estuary since the issuance of the 1980 Interpretive Report. The major findings of that report, which were the basis for the issuance of the NPOES permit, were:

1. There is no persuasive evidence of abnormal trends in rela-tive abundance of either larvae or juveniles and adults of representative taxa as a result of the plant's operation.

2. There is no persuasive evidence of the ' plant's preventing or observably changing migration of larvae and juveniles to preferred upstream or downstream nursery areas.

3. There is no persuasive evidence of the plant's preventing or observably changing migration of larvae into and out of the Snow's Marsh /Walden Creek marsh complet or their full use of this area.

I 4 The estuary is responding to normal gross environmental variables, such as temperature and salinity, which are the I primary determinancs of ultimate population levels and which override the lesser effects of plant entrainment and impingement on system productivity.

l 5. The estuary is supporting populations very similar to other estuaries uninfluenced by power plant withdrawals.

I 6. There is no persuasive evidence of any change in or altera-tions of the structure of nekton communities in the estu-ary.

k I

CP&L has continued a biological monitoring program since the issuance of the NPOES permit in 1981. This report summarizes and interprets these new data in light of the previous findings and demonstrates that the early r findings are substantiated.

Objectives The objectives of this Interpretive Report are:

1. To describe populations of commercially and recreationally important species of fish and shellfish of the estuary

, under operating conditions of the NPDES permit require-ments.

2. To describe the reduction in entrainment and impingement of fish and shellfish as a result of the installation of a permanent diversion device, fine-mesh screens, and the

( utilization of flow rinimization.

This report is organized into the following sections:

g Section 1 is an overview description of the plant and the estuary and I describes the basis for the biological study program and the permit-required plant modifications to reduce entrainment and impingement.

Section 2 describes the water quality monitoring program and why it is important to know when, where, and how temperature and salinity changes occur in the river.

Section 3 addresses the larval and postlarval stages sf fish and shellfish in the river; trends seen over the years in species occurrence, distribution, and abundance; and whether the trends indicate any substan-tive changes attributable to plant operation.

Sections 4 and 5 address trends in juvenile / adult fish and shellfish populations. Section 4 covers the high marsh program and the occurrence of juveniles in four tidal creeks located in dif ferent areas of the estu-l ary. Trends in the occurrence of nekton (free-swimming juvenile and adult organisms) in the open waters of the estuary are discussed in Section 5.

3

D e

l Sections 6 and 7 deal with the removal of fish and shellfish from the estuarine system through entrainment and impingement. Numbers entrained seasonally, annual trends in entrainment, and the reduction in these num-bers due to flow minimization and fine. mesh screens are discussed in Sec-tion 6. Section 7 addresses impingement on the plant's traveling screens I of both larvae and juvenile / adult fish and shellfish. The numbers and weights of impinged organisms are adjusted for survival (as documented in

.I Section 9) and an estimate of loss due to impingement is presented.

Section 8 describes the fish diversion structure constructed at the mouth of the intake canal and the subsequent decline in larger organisms impinged on the traveling screens.

Section 9 assesses the survival by size of the dif ferent species impinged on the rotating screens and returned to the estuary via a 1.43-km sluice. The application of these numbers to the numbers of organisms impinged allows the calculation of the number of impinged organisms now being returned to the estuary alive.

Section 10 is a summary of the preceding sections and lists the find-l ings of the past ten years with respect to the effect of plant operations on fish and shellfish of the estuary.

The Brunswick Steam Electric Plant The Brunswick Steam Electric Plant is a two-unit nuclear station 10-cated adjacent to the estuary about 9.2-km upstream from the mouth of the Cape Fear River (Figure 1). The two 790-MWe units (maximum dependable capacity) were commercially operable in November 1975 (Unit 2) and in March 1977 (Unit 1). The plant's cooling system withdraws water predomi-nantly from the surface layer of the river (Carpenter and Yonts 1979; Weinstein 1979b) through an approximately 4.8-km intake canal and channel that bisects Snow's Marsh. Cooling water is discharged to the Atlantic Ocean through an approximately 9.6-km discharge canal.

l

s

- Permit Requirements in January 1981, Carolina Power & Light Company was reissued a permit to discharge co. g water from the plant to the Atlantic Ocean under the Nathnal Pollutant ischarge Elimination System.

CP&L agreed to several modifications as a mitigative measure to re-duce entrainment and impingement. A permanent fish diversion structur e

, was built across the mouth of the intake canal in November 1982 to reduce the susceptibility of larger fish and shellfish to impingement. The effectiveness of the structure is discussed in Section 8 of this report.

In addition, fine-mesh (1-mm) screens were installed on two of the four traveling screen assemblies on each unit in July 1983 to reduce entrain-I ment, and a fish return system was built to return impinged organisms to the Cape Fear River via a small tidal creek that runs into Walden Creek (Figure 2). The effectiveness of fine-mesh screens is addressed in Sec-tion 6 of this report. The NPOES permit also required seasonal reductions in the volume of cooling water used by each of the plant's two units as follows:

, Water Temperature $ 65'F Water Temperature > 65'F

.m (typically November 15- (typically aaril 15-l April 15) Novembc: 15)

Previous flow 1105 1205 (cubic feet /second)

Maximum unit flow i with flow minimi-zation (cubic feet /

605 915 second)

(A flow of 1105 cubic feet /second is allowed when the water temperature is

> 85*F, but this condition rarely occurs.)

The permit further states that two fine-mesh screens per unit should be in operation at all times. Because a flow of 605 cubic feet per second is achieved with only two intake pumps in operation, only fine-mesh screens were in operation in most cases during the November to April period.

5

Two studies were conducted in 1985 to evaluate these mitigative meas-

- ures. Larval impingement sampling was initiated to determine how many larvae were impinged on the fine-mesh traveling screens. Laboratory sur-vival studies were conducted to detcrmine what percentage of impinged orgar. isms were returned to the estuary alive via the fish return system.

The Cape Fear Estuary (CFE) and Its Biological Components The Cape Fear Estuary is located wnere freshwater runoff f rom the Cape Fear River meets the saline waters of the Atlantic Ocean. The es.

tuary contains many scattered islands, marshes, and tidal flats, it ranges from about 0.6 to 3.3 km in width and extends about 45.1 km from the river mouth to the general location of the salt boundary near Wilming-ton, North Carolina. The estuary resembles an elongated shallow bay with I depths around 1 meter, except for the narrow but deep (12.1-m) ship channel that has been dredged by the Corps of Engineers to the daep-water port at Wilmington.

The Cape Fear Estuary has a large exchange of water with the Atlantic Ocean. This large exchange, which consists of approximately 80% of the water over a 12-hour period, takes place in the lower estuary below the constriction at Sunny Point (Carpenter and Yonts 1979; Pietrafesa and Purba; manuscript in preparation). The plant's intake canal is located below this constriction and is in this area of large tidal exchanga.

The estuary above Sunny Point is typical of coastal plain estuaries with a two-layered flow regime created - by saltwater intrusion along the bottom. Ocean water (and organisms) can also enter the estuary above Sunny Point through Snow's Cut which connects the river via the Intra-coastal Waterway and Carolina Beach inlet to the Atlantic Ocean (Fig-ure 1).

The major categories of aquatic biota found in the estuary consist of phytoplankton (floating microscopic plants), zooplankton (floating micro-scopic animals), planktonic or semiplanktonic larvae and postlarvae of fish and shellfish (growth stages from the egg to the juvenile stage), and nekten (juvenile to adult fish and shellfish).

6

. . .~ . - -.- __ .. -, .

I Phytoplankton and Zooplankton are ubiquitous in the lower estuary and are influenced mainly by the ocean. As such, they are in large supply _and do not uniquely use the estuary as a nursery area. Previous studies have shown no impact due to the plant (Birkhead et al. 1979). Therefore, these biota are no longer monitored by CP&L.

.I Larval and postlarval stages of fish and shellfish, most of which are ocean-spawned, are of interest because they use the estuary as a " nursery" area. Also, their recruitment pathways pass by the plant's intake, thus exposing some of them to possible entrainment and impingement. Nekton consists of a mixture of ocean-spawned species, a few anadromous species (those that live in the ocean but migrate into freshwater to spawn), and resident species who live their entire life in the estuary.

~

Nekton are g monitored because juvenile and adult impingement is made up of nektonic 5 organisms.

,l A summary of the biological monitoring programs that has been con-ducted at the BSEP are summarized in Table 1.

E 2.0 WATER QUALITY

~I Salinity and temperature influence the_ spatial and seasonal distribu-tions of estuarine species. Salinity nas been demonstrated by Weinstein et al. (1980) to be an important factor influencing the spatial distribu-tions. Fluctuations in salinity caused primarily by variable freshwater inflow produce changes in the abundance of species in an area. Tempera-ture influences seasonal distributions.

VE The estuary is subject to highly variable and relatively large in-l flows of freshwater from the Cape " ear River drainage basin. The two-layered flow regime typical of coastal plain estuaries is usually present in the portion of the estuary above Sunny Point (Carpenter and Yonts 1979). There is a net upstream flow of more saline water in the lower layer and a net seaward flow of less saline water in the upper layer. The I portion of the estuary seaward of Sunny Point, in which the plant's intake canal is located, is typical of a marine-oriented, well-mixed regime.

I

I Complex water circulation patterns, vigorous tidal action, and high-exchange ratios with the ocean characterize this reach of the estuary which acts as an extension of the nearby Coastal Zone (Carpenter and Yonts I 1979; LMS 1980).

In 1982 the present water quality program was initiated to better characterize how the estuary was responding to freshwater flow using salinity as an indicator. Temperature and salinity measurements were recorded from the surf ace and the bottom of different areas in the estu-ary. Nine water quality stations were sampled weekly. Seven of these stations were located in the ship channel of the river between Southport and Wilmington. The remaining two stations were located in shallow creek systems north (Walden Creek) and south (Dutchman Creek) of the plant site.

Water quality data were also collected from the high marsh and nekton programs.

Salinity values ranged from zero upriver to virtually full-Strength

~

ocean water (36.0 ppt) around the mouth of the river (Figure 3). Overall, minimum salinities were usually observed around January / February and max-imum salinities in late summer ( > 20 ppt at the uppermost station).

However, data from the summer of 1984 proved to be an exception to the expected trends (Figure 3). An unseasonably heavy storm in the upper CFR basin during July increased the freshwater flow to approximately three times the expected level (pers comm., Curtis Gunter, USGS); also, shortly thereafter, Hurricane Diana passed over the CFE dumping approximately

. 40 cm of precipitation. These two events were not normal or frequent occurrences for this time of year. This change was clearly illustrated when data from previous years (1976-1983) were compared with the expected late summer peak in salinity values (CP&L 1984).

The changes in seasons are the main factor influencing water tempera-ture in the estuary. Maximum temperatures (27*-32*C) are normally ob-served during late summer in the creeks and downstream areas. Minimum temperatures (< 4.0* C) are usually observed during late winter in the creeks and upriver areas (Figure 4).

I I 8

I The same circulation patterns seen by Carpenter and Yonts (1979) are l

still present in the estuary today. When bottom salinities from Station HG15 (located in the seaward reach below Sunny Point) were plotted, it was observed that these values remained fairly high throughout the year, while the values at Station HG29 (located approximately 15 km above HG15) tended J to correspond to the pattern of increased flows (lower salinities) in January / February and decreased flows (high salinities) in late summer.

When the results from Station HG29 were compared to the results from Sta-tion HG42 (approximately 8 km upstream of HG29), the same pattern of salinity values responding directly to variations in river flow can be observed (Figure 3). These observations indicate that the historical patterns seen earlier are still in effect and have been unaffected by the operation of the plant.

=

3.0 RIVER LARVAL FISH The majority of commercially and/or recreationally important fish larvae collected in the CFE are transients. These larvae are spawned offshore and enter the estuary to avoid predation and to feed in the nutrient-rich environment. The major objective of the river la, val fish ,

g program was to determine if any yearly variation in populations of these B organisms could be attributed to the operation of the plant's cooling system. Consequently, larval and postlarval fish, shrimp, and crabs have been collected from the estuary since 1973. This study provides informa-

~

tion on the species composition, seasonality, abundance, spatial distribu-tion, and size distribution of larval organisms in the estuary. Long-term trends in larval abundance are presented, and specific questions concern-ing the impact on larval populations in Walden Creek are addressed.

Initial studies in 1973 were primarily concerned with identifying the seasonality (time of year when organisms are present), abundance, length frequency (frequency of occurrence of size classes), and species of larvae and postlarvae utilizing the estuary. The sampling frequency and the size of the study area were expanded during 1976-1978 to better define the areas of residence of larval species, behavioral mechanisms used by organ-isms to move into the estuary, and seasonal differences in species compo-sition (Copeland et al. 1979). Studies conducted by CP&L since 1979 were 9

reduced in scope yet designed to provide data which could be compared to earlier studies of the estuary, allowing for the analysis of Icng-term L trends. (CP&L 1980c,1982,1983,1984, and 1985). Length-frequency data from uprivt and downriver areas were compared to confirm that organisms were accumulating and establishing residence upriver (Copeland et al.

1979; CP&L 1985).

Methods of collecting larvae and postlarvae have been standardized since 1976. Replicate surface and bottom samples were collected simultan-eously for 5 minutes using 1-m diameter, 505-micron mesh nets mounted in rectangulre- frames. Surface frames were 80 x 80 cm and the bottom frames, mounted in a sled, were 104 x 51.4 cm. Flowmeters were used to determine I the volume of water filtered 50 that organism densities could be computed.

g Early studies were conducted four times during a 24-hour period. Begin-E ning in 1980, sampling at seven stations (Figure 1) was conducted only at night after it was determined that population estimates derived from night samples were not different from those derived from samples collected four times in 24-hours (CP&L 1982),

1 A special study was begun in 1979 to better define the vertical dis-tribution and movement of larvae during both tide and photoperiod changes.

The objective of this study was to assess the effectiveness of the river larval fish sampling program which collects only nightly surf ace and bot-tom samples. A 0.5-m, 505-micron mesh Tucker trawl was used to sample l arv'a l abundance at discrete depths. Twenty-four-hour sampling trips conducted during the peak period of recruitment for spot and croaker con-firmed a diel movement. During the day, these species are concentrated near the bottom but at night they (especially spot) move up in the water column (Copeland et al. 1979; CP&L 1980c, 1982, 1983, 1984, and 1985; Weinstein et al. 1980).

Discrete depth sampling was not conducted at the identical time that river larval fish samples were taken. To account for potential errors when comparing river larval fish and discrete depth densities resulting f rom dif f erent times of the year, an additional special study was con-ducted that matched river larval fish and discrete depth samples on a 10

temporal, tidal, and photoperiod basis. Total water-column density esti-I mates were not significantly different between the two sartpling gears indicating that means derived from surf ace / bottom samples were comparable to means derived from multiple-level sampling (CP&L 1985).

In the river larval fish monitoring program, eight taxa comprised over 90% of the total catch, and the relative abundance of these taxa was similar during each of the past ten years (Table 2). Anchovy was the most abundant each year. Croaker, portunid megalops, and Gobiosorna spp. were the next most abundant followed by spot, Penaeus spp., menhaden, and silverside larvae. Some differences among years occurred due to environ.

mental variables such as cold winters or high freshwater flow (Copeland et

~I al. 1979), but these year-to-year variations in estuarine ecosystems are g considered normal, g

The seasonality of larval species in the estuary has remained un-changed during the past eight years (Figure 5). Two distinct periods of abundance, summer and winter, were Identified by Copeland et al. (1979).

The winter species occurred from October through March and consisted mainly of spot, croaker, menhaden, and brown shrimp. The summer species occurred from May through September and consisted primarily of anchovy, goby, and pink and white shrimp. Again, yearly variations occurred (for example in 1980) when low freshwater flow and extended warm temperatures shortened the anchovy spawning season (Figure 6).

. The total numbers of larval organisms collected in the estuary have shown significant increases from 1977 through 1984 (Table 3). This in-crease is due primarily to increases in anchovy, Gobionellus spp., penaeid shrimp, and croaker densities. No decreases in densities were found for any species examined.

The spatial distribution of larvae in the estuary continued to be the

~

same as described by Copeland et al. (1979). Flounder, shrimp, and spot tended to move out of the channel area and into the shallows; croaker utilized the upriver channel areas much more extensively than did other species; menhaden moved upstream to low-salinity areas; and anchovy 11

preferred areas of higher salinity. FluctNtions in spatial distribution y have occ'Jrred. For instance, the distance upriver that Croaker accumulate L is influenced by the amount of freshwater flow. During periods of high flow, croaker are located further downriver than usual (CP&L 1985).

L, Larvae are able to move past the plant and establish residence up-river. For example, croaker are four/ in the upriver areas, and a greater proportion of larger individuals are found upriver (Figure 7) indicating larvae are able to migrate to upriver nursery areas, accumulate, and grow unaf fected by the operation of the plant. Copeland et al. (1979) de-scribed similar upriver concentrations and size differences.

Larvae in the immediate vicinity of the plant (Walden Creek) are also g not significently affected by the plant. Overall, densities of larvae in N Walden Creek nave significantly increased through time. Results of time-series analyses indicate significant increases in the occurrence of total larval and postlarval organisms (Table 3). The densities of total organ-isms are not statistically different from densities in Dutchman Creek, a creek located ll.2-km downstream from the plant's intake and chosen as a site for comparison which would be unaf fected by the plant's operation (Table 4).

Sampling of larvae from the estuary during the past ten years indicates there has been no change in species composition, seasonality, abundance, distribution or size of larvae in the estuary which can be attrik +.ed to che operation of the plant. Some year-to-year uriation has been ooserved over the ten-year period but thest can be exp mined by envi-ronmental fluctuations. The mechanisms that control larval populations within the estuary remain unchanged after ten years of plant operation.

4.0 HIGH MARSH It has been estimated that in the southeastern United States, as much as 93% of the commercial fish, sportfish, and shellfish spend a portion of their lives in estuaries (McHugh 1967). The marshes of the estuary pro-vide nursery areas for many of these commercially and/or recreationally 12

important species of fish and shellfish. Because the plant removes water from the lower estuary, individuals migrating to nursery areas are sub-jected to possible cropping. Biological studies were undertaken in 1976 I to determine if the recruitment of ocean-spawned species to the marshes was affected by plant operation. The primary objective nf tne study was to determine if the utilization of the nurseries was altered due to plant operations. This was accomplished by investigating the seasonality, abun-dance, and spatial distribution of pc, tiarval and juvenile fish and shell-fish in the marshes of the estuary.

I Beginning in 1980, sampling stations were located in four tidal creek systems that differed in salinity and sediment characteristics. These creek systems, located from the lower estuary to the upper estuary, were Baldhead Creek, Walden Creek, Mott's Bay, and Alligator Creek (Figure 1). Samples were collected a7 low tide approximately every three weeks.

To sample the various habitats within each creek system, a 3.2-m small mesh (6.4-mm) trawl and a 15.2-m small mesh (6.4-mm) seine were used.

The number of organisms collected by each gear was divide < by the number of samples collected to derive a catch-per-unit-ef fort (CPUE) for iI each species. The CPUE data were used in all of the analyses. Length-frequency distributions were used for determining periods of recruitment.

. Spatial distributions of organisms and the effects that temperature, salinity, and sediment grain size and organics had on selected ' species I were analyzed. Significant increasing or decreasing trends over the years were determined using time-series analyses.

With the exception of bay anchovy, which is estuarine-spawned, the composition of postlarval and juvenile communities within the marshes has been dolinated by ocean-spawned fish and shellfish species from 1976 through 1984. The dominant finfish were spot, bay anchovy, and menhaden.

Tne most abundant commercial shellfish were brown shrimp and blue crab (CP&L 1985). <

I 13

Previous studies in the estuary have indicated taat various species

,- show preferences for selected salinity ranges. The pr:ferences for dif-fering salinity regimes exhibited by the dominant species have not changed substantially over the past nine years indicating there has been stability within the estuary (Copeland and Hodson 1977; Weinstein et al.1980; Table 5). Southern flounder, spot, croaker, st ' ped mullet, menhaden, and blue crab were most abundant in low-salinity arcs; while mummichog and penaeid shrimp were more abundant in medium- to high-salinity areas. Atlantic silverside, white mullet, and bay anchovy were collected from high-salinity areas. The sediment variables in the study areas appeared to have minor effects on the distributions of most organisms.

The distribution of the dominant species in the estuary was dictated by the upriver to downriver salinity gradient (Table 6). The results of this study were similar to previous studies (Copeland et al. 1979; Wein-stein 1979c) which indicated that species which prefer areas upriver can successfully migrate past the plant intake canal and establish residence in the middle to upper estuary nurseries.

Previous studies showed that most species concentrate in the upstream areas of the tidal creeks (Purvis 1976; Weinstein et al. 1980). Data collected during 1981-1984 confirmed this spatial distribution for species

from the estuary (Table 7). Furthermore, spatial distribution was similar in Walden Creek and Baldhead Creek providing further evidence that the plant operations did not disturb the natural spatial distribution of organisms in the tidal creeks. Walden Creek is located adjacent to the intake canal, whereas Baldhead Creek is located downriver and away from the influence of the plant.

Trends in abundance from 1981 through 1984 appeared to be influenced by the high freshwater flows that occurred in 1983 and in 1984 Organisms that preferred less saline waters tended to increase in abundance, whereas the opposite was noted for organisms that preferred more saline water.

For example, southern flounder, a species which prefers nursery areas of I low salinity, increased significantly in all areas of the estuary except Baldhead Creek (Table 8). The freshwater flows probably increased 14

I preferred southern flounder habitat throughout the estuary. Conversely, spot and penaeid shrimp decreased in abundance in the upper estuary, while these and many other species increated in the lower estuary during 1981-1984.

To determine if the estuary has been used over the past four years to the extent it had been used in previous years, comparisons between more recent data and past data were made. This was accomplished by determining the standing crops of several species collected with trawls from 1981 through 1984 and comparing these to the standing crops determined by rote-none and seines in 1977 and 1978. The standing crops of several species in the Cape Fear Estuary were also compared to similar estuaries in North Carolina which have no power plants.

it is important to keep in mind that two dif ferent gear types were used to estimate the standing crops. The standing crop estimates of earlier studies and those from other estuaries were determined using rotenone and seines as collection methods. However, for the purpose of determining drastic changes in tne estuary, these comparirons were made.

Table 9 presents standing crops which are unadjusted for gear ef ficien-cies. Weinstein and Davis (1980) determined that the mean gear efficien-  ;

cies for seine and rotenone were 46.1% and 44.0%, respectively. Kjelson (1974) determined that the gear efficiency of a trawl similar in I et al.

size to the one used from 1981 to 1984 was 30% to 69% for demersal

.g- (bottom-dwelling) and semidemersal fish. These efficiencies were deter-5 mined for trawl collections from brackish Spartina marsh creeks similar in size to those sampled in the Cape Fear Estuary.

The information presented in Table 9 indicates that no drastic changes have occurred from 1977 through 1984. Standing crops in the Cape Fear Estuary in 1977 and 1978 were similar to those of other estuaries in North Carolina (Marshall 1976). This continues to be true for the stand- ,

ing crops estimated from 1981 through 1984 The maximum abundance and minimum size of most species were asso-ciated with peak recruitment. After recruitment ended, an increase in I {

L inod al length became apparent. During the several month residence and

- growth period, most species declined in numbers in the marsh due to emi-gration and natural mortality. Spot, menhaden, croaker, blue crab, striped mullet, and flounder were more abundant in late winter and early L spring. Bay anchovy, penaeid shr'mp, 3hite mullet, Atlantic silverside, and mummicheg were more abundant during late spring and summer. Seasonal

~

dis eibutions were sin,ilar from 1981 through 1984 (Table 10) and corre-spond with data reparted from 1976 throu[' 1977 (Weinstein et al. 1980).

l Sampling of postlarval and juvenile 'ish and invertebratts in the tidal creeks over the past nine years indicates there has been no major change in the pret erred salinity regimes, spatial distributions, seasonal-I ity, or abundances of organisms in the estuary which can be attributed to the operation of the plant. Any changes that occurred were directly or indirectly related to normal environmental variations.

5.0 NEKTON Many species of commercially and recreationally important fish and shellfish spend a portion of their first year in the marshes of the Cape Fear Estuary and then migrate to the ocean as juvenile and adult members of the nekton (free-swimming) community. Use of estuarine water for cool.

ing purposes introduces the possibility of impingement of some of these nektonic organisms. The objectives of the nekten program were to monitor the seasonality, abundance, and spatial distribution of the dominant juve.

nile and adult fish and shellfish to determine whether the plant has had I an affect on their abundance or ha, limited the movement of these organ-isms to and from their normal nursery areas.

Sampling of the juvenile and adult fish and shellfish in the open waters of the estuary began in 1973 with the studies of Schwart2 et al.

(1979a) and continued through 1978. Sampling has continued from 1979 to the present b .P&L personnel.

Eleven stations in the estuary and three stations in the intake canal were *ampled every three weeks with a 6.4-m otter trawl. Station loca-tions ranged from near the mouth of the river to Wilmington (figure 1).

16

I Organisms were sorted by species, measured, and count?d. Trie number of I organisms collected was divided by the number of trawl samples taken to prie lde a catch-per-unit-ef fort (CPUE) for each species. Length-frequer.cy distributions were examined to differentiate size classes of selected species. Time-series analysis wts used to determine periodic ity and trends in abundance.

In 1984, bay unchovy, spot, croaker, and menhaden comprised 81% of the total catch. Dass shrimp, brown shrimp, and blue crab ranked nExt in abundance and comprised 17% of the total catch. These species have his-torically been tae dominant fish and invertebrate species collected in the estuary by the nekton program and by other researchers, indicating little I change in relative abundance of these species (Birkher' et al. 1979 Schwartz et al. 1979a; CP&L 1982, 1983, 1984, and 1985).

Catches of the dominant species were seasonal and peaked at approxi-mately the same time each year (Figure 8). Summ:.e species, such as brown shrimp, exhibited peak abundance in trawl catches during June or July of each year (figure 9). Winter species, such as spot, were more abundant from approximately February through April (figure 10). These periods of abundance are similar to those from 1973 through 1978 as reported by Schwartz et al. (19798).

I The abundances of nektonic organhms in the estuary have shown no significant change other than natural yearly fluctuations. This is ex-plainable by the cyclic nature in abundances of many species and changing temperature and sa'inity regimes (Birkhead et al. 1979; Schwartz et al.

l 1979a; CP&L 1985). The yearly abundance of total organisms remained rela.

tively constant through 1982 and then decreased slightly in 1983 and 1984 (Figure 8). This was caus:J by a decreate in annual species such as brown shrimp (figure 9) and was attributed to severe winter conditions and unu.

sual rainf all patterns. Poor catches of brown shrimp were also reported for the other major estuaries in the state (Street 1985). finfish, such as spot, alto exhibited trends in abundance which appear cyclic (figure I 10).

I 17

I fish and shellfish distributions are explained by water depth and I distance along a salinity gradient from downriver to upriver (CP&L 1985).

Spot were associated with the lower estuary, while menhaden and croaker were associated with the midestuarine areas (Table 11). Brown shrimp were associated with the inner and midestuarine areas. These distributions have remained unchanged f rom previous years and are similar to what is typically found in other North Carolina estuaries (Schwartz 1979a; CP&L l 1980c, 1982, 1983, 1984, and 1965).

Operation of the plant has not adversely a 'fected the populations of nektonic organisms residing in the Cape rear Estuary. Species composition I and seasonality have remained unchanged since 1979 and are similar to what previous researchers reported from 1973 through 1978. Changes in the yearly abundan;e of total organisms are related to the cyclic nature of I many species and environmental conditions and are not the result of plant

, operation. Movement of organisms into and out of the estuary has not been affected by plant operation since the spatial distributions of these organistrs have remained unchanged.

I 6.0 ENTRAINMENT I Power plants which utilize a once-through cooling system inevitably entrain aquatic organisms suspended in the water column resulting in the

,I loss of larval and postlarval organisms from the estuary. Therefore, to document this loss, entraintrent sampling was conducted to determine the density and number of larval and postlarval fish and shellfish that were entrained by the plant. Entrainment studies to determine species composi-tion, seasonality, and abundance of entrained organisms were conducted in the discharge weir by N.C. State University from May 1974 through August 1978 (Copeland e.t al . 1979). CP&L has conducted the entrL nment studies since September 1978.

I The NPDES permit required le implementation of two mit 19ative mea-I sures aimed at reducing the loss of larval and postlarval organisms due to entrainment. The iirst measure was the installation of fine-mesh (1-mm) on two of the four traveling screens bays per unit. The second measure I 18

I was the enactment of a flow-minimitation regime whereby the amount of I water withdrawn from the estuary was reduced. For implementation dates of these measures, see figure 11. Entrainment data have been used to assess the changes due to these measures.

Entrainment samples were collected weekly with 0.5-m diameter. 505-micron mesh nets which were placed for five minutes in one of the two discharge weirs. Replicate sampics were taken during the day and the night over a 24-hour period. Flonmeters in the nets were used to deter-mine the volume of water seived from which the de'isity of organisms en-trained was calculated.

I Two periods of peak abundance have been identified in entrainment--a winter peak .,nsisting mainly of spot, croaker, flounder, mer,haden, mul-I let, and brc e shrimo and a summer peak consisting mainly of seatrout, anchovies, gobies, and pink and white shrimp. These seasonalities have remained unchanged since 1974. These patterns correspond with major peak in density of the same larvae and postlarvae seen in the ri"er larval fish program (CP&L 1982, 1983, 1984, and 1985). The diel (day / night) variation has also remained the same with more organisms being entrained at night than during the day (figure 12).

A special study was conducted on three occasions to determine the effectiveness of fine-mesh screens in reducing entrainment. On each occa-sion, entrainment collection procedures were followed but the type of I intake screen used was alternated. On two occasions, a 24-hour sampling period using 9.4-mm mesh screens was followed by a 24-hour sampling period using 1-mm mesh screens. On the other occasion, sampling was conducted simultaneously in the two discharge weirs when one unit was using only fine mesh and the other unit was using only 9.4-mm mesh. Resul , show an 82% reduction in the mean density of total fish entrained when fine-mesh screens were used. The reduction by species was 69% for anchovy, 88% for croaker, 58% for spot, and 70% for Goblonellus spp. (Table 12).

I To determine if reducing the amount of water needed for cocling would substantidlly reduce the numbers of organisms entrained, comparisons using I

I 19

I observed entrainment rates (number / day) were made between historicel flows I (Hogarth and Nichols 1981) and observed flows under flow minimitation.

The reduction in numbers of organisms entrained per day from historical flows ranged f rom 26.5% to 47.4% depending on which flow regime was in effect (Tabla 13). By applying the 82% reduction in density due to fine-j mesh screens (Tabie 12) to the observed densities, an estimate of the

} entrainment rate under historical flows using standard-mesh screens can be l obtained f or the periods November 22, 1983, through April 1984 and Octo-j ber 30, 1984, through April 18, 1985. These were periods of operat ion using strictly fine-mesh screens ar d the greatest reduction in flow.

l j Comparing estimated rates using historical flows and standard-mesh screens

! to observed rates under flow minimization and fine-mesh screens, the per.

f cent reduction due to both modifications was 90% (Table 13).

i Entrainment densities have decreased due to the installation of fine-mesh screens (Table 12 and Figure 13), but the percent composition of entrainment density by species has remained unchanged given year-to-year

, variations (Table 14). Prior to the installation of fine-mesh screens,

entrainment densities most closely resemtled the densities seen at Station

) 25 of the river iarval fish program. A plot of the ratio of entrainment densities to Station 25 densities shows that the ratio was close to 1:1 (Figure 14). The low ratio seen in August of 1982 is due to the extremely high numbers of Coblonellus spp. caught in the river. Only one trip per month is made during June, July, and August in the river larval fish pro-gram, while the entrainment progrei samples once per week. Because the

! monthly mean for the river is bated on only one trip, density estimates could be casily skewed upward if the trip coincided with the peak of abun-

dance which it did in this casc. After July 1983 (completion ? fine-mesh screen installation) entrainment densities have declined and the ratio appears smaller; therefore, the plant is entraining fewer organisms, even

! though the potential for entrainment has remained the same.

In the ten years that entrainment studies have been conducted, no Change in the patterns of seasonality, abundance, and diel variation of

I

...,.---,,,...,e,-.. .-,._-~.---..,------....-.,-,..,,.....,,-,.,.--..,-n ,..~.,--.,,,-,--,-.--..--...--,..,-.._,_--.,-,,,,.,,,,.-+-,-.,-,~r.-,

T ngndun ^ trained has been observed.

. A reduction in the number of I

• Odtnu, entrained due to flow minimization and a reduction in the den-3 , ;y of organisms entrained due to the installation of fine-mesh screens nas been observed.

7.0 IMPINGEMENT The industrial use of water for cooling purposes results in larger organisms being impinged or trapped on screens in front of the intake pumps, impingement studies have been conducted at the plant since 1974 to determine the numbei of juvenile and adult fish and shellfish cropped from estuarine populations. Historically, impingement concisted of organisms impinged on 9.4-mm traveling screens. The numbers 6,'- .izes of organisms impinged changed because of plant intake modifications. A diversion structure (construction finished in November 1982) and fine-mesh screens were installed and a flow-minimization scheme was implemented.

Historically (1977-1982), 93Y. of the impingement catch was organisms over 40 mm in length; therefore, only organisms greater than 40 mm were analyzed in the juvenile and adult program, while those 40 mm or less were analyzed in the larval impingement program.

Juvenile and Adult Impingement Several changes have taken place in the methodt used to collect juve-nile and adult organisms impinged on the intake traveling screens due to plant modifications. Presently a sieve is used in the return sluice to catch juvenile and adult organisms impinged in one 24-hour period each week. The mesh of the sieve is similar to the 9.4-mm mesh of the original intake traveling screens. The weetly sample is expanded to estimate total monthly and yearly impingement. The following table presents impingement catch in terms of a density (number of organisms per million cubic meters of water entrained through the plant) to account for fluctuating plant operations. The 1977 through 1982 impingement data represent the pre-modification sampling period, while the 1984 data were taken with the modifications in place. The 1983 data are not used because sampling meth-odologies were being evaluated; consequently, only six months of data were collected in 1983.

21

I Numbers and weights of organisms impinged per I mil _ lion cubic meters of water passed through the p h I No. of Million Cubic Year Number Weight (kgl Meters 1977 124,593 743 1529 124,289 I 1978 1979 1980 91,060 79,647 865 464 523 1819 1525 1322 l 1981 1982 74,286 204,162 514 709 1294 1182 1977-1982 mean *15,340 636 1445 1984 66,398(43% reduction) 210 (67% reduction) 901 The reduction in the 1984 juvenile and adult impingement density was

, primarily attributed to the diversion structure excluding larger organisms from the intake canal.

T

= The 1984 catch consisted of smaller organisms when compared to pre-modification catches. Cumulative length distributions for bay anchovy

. (Figure 15), menhaden (Figure 16), spot (Figure 17), and croaker (fig-ure 18) confirm that smaller organisms were being impinged in 1984 as compared to 1981. Larger organisms were excluded from the intake canal,

(

while the smaller organisms were able to enter the intake canal through the diversion structure screens, further, the fine-mesh screens impinged organisms that previously had been entrained. This is especially true for bry anchovy. Altnough most bay anchovy could probably enter the intake canal through the diversion screens, the fine-mesh screens impinged small size classes which were previously entrained. The modal lengths in 1984 I were 10 to 25 mm less than in 1981 (Figure 19).

When survival data (Section 9) are applied to the ten dominant species impinged during 1984, results show that 16% by number and 43% by j weight were returned to the estuary alive (Table 15). These ten species accounted for over 90% of the total impingement catch. Excluding l anchovies and other species not tested, over 53% by number of those ten 22

= _ . _

I species survived (813,000 of the 1,531,000 impinged). The weight of juve-nile and adult organisms not surviving impingement are presented below along with the 1984 North Carolina Southern District commercial landings I (3treet 1985).

1984 Loss to 1984 N.C. Southern Juvenile and Adult District Commercial Species _Imoingement (kg)_ Landings (kg) Percent Penaeia shrimp 158 1,211,731 0.0130 Croaker 197 164,167 0.1199 Blue crab 266 446,265 0.0596 Spot 133,871 0.1643 I Menhaden

• 220 4377 66,622,517 0.0066

• Data by district not available--statewide landing reported.

Juvenile and adult impingement was substantially reduced during 1984.

Additionally, survival of impinged organisms was documented with many organisms returned to the estuary alive. The new fish diversion structure and nekton return system substantially reduced any impact that the plant may have had on the estuary.

Larval and Postlarval Impingement

.I The larval impingeme6t program was begun in January 1984 to provide an estimate of the total number of larvae and postlarvae being impinged and returned to the estuary. Prior to installation of fine-mesh screens, many of these organisms would have been entrained and lost to the system.

Survival percentages applied to these estimated numbers give an assessment of the success of fine-mosh screens.

Samples were collected by placing a 505-micron mesh net in the return

,I sluice such that the entire water column was filtered. Five-minute samples were collected on mid and slack tides over one twenty-four-hour I period per week. During periods of heavy impingement (> 500 organisms /

sample), samples were subsampled in the laboratory with at least 2*% of the sample weight being retained for processing.

I

A total of 5.7 x 108 1arval organisms representing 99 taxa was im-pinged during 1984 Croaker and spot were the dominant species comprising 22.9% and 20.3%, respectively, of the total Catch.

The typical winter and summer peaks in abundance observed in the entrainment and river larval fish programs were also observed in larval impingement. The seasonality and diel patterns for individual species also closely followed the other programs. The most penacid shrimp, Goblonellus spp., and portunid megalops were impinged during high slack tides, and the most seatrout were impinged during low slack tides. For all othL species, there was no significant difference in numbers impinged among tidal stages.

1 Survival percentages for each species studied were applied to the estimated total number impinged and are presented in Table 16. Survival estimates for slow intake screen speed ranged from 8.9% for spot to 86.3%

for portunid megalops. Estimates f rom f ast screen rutation ranged from 12.6% for weakfish to 90.2% for Penaeus postlarvae. Bay anchovy showed no survival at either speed. The eight taxa listed account for 79% of the total larvae impinged. If the traveling screens had been run on f ast rotation for the entire study period, approximately 49% would have sur-vived resulting in almost 39% of the total catch being returned alive to the estuary.

Hany of the larval organisms impinged during 1984 had previously been I entrained and 100% mortality was accepted since they were lost to the estuarine system. The installation of fine-mesh screens and the return system has allowed for a percentage of these organisms to now be returned alive to the estuary.

I impingement--Comoined Effects 1 As a result of mitigation efforts, the size composition of the impingement catch has shifted towards smaller organisms. Two factors I appear to be largely responsible for this change--fine-mesh screens and the fish diversion structure.

24 E

I Fine-mesh screening has caused small, previously entrained organisms to instead become impinged. This results in a net benefit since survival of these individuals, in most cases, is considerably higher (Section 9.0)

I than it would have been had they been entrained.

The most important shif t, howe cr. results from the fish diversion structure (Section 8.0). This device excludes most of the larger fish from the intake. Reduction in the cropping rate of these individuals is an especially : ictive mitigative measure because these organisms have survived the hi9, initial mortality. The natural mortality rate for early life stages of most fishes is extremely high, of ten exceeding 40%-50% per day but decreases considerably with increasing age (Dahlherg 1979).

Organisms having survived this initial mortality are much more likely to survive to adulthood and contribute to the propagation of the species.

I 8.0 FISH O! VERSION STRUCTURE The diversion structure, located at the mouth of the intake canal where it intersects Snow's Marsh (Figure 2), was completed in November 1982. The purpose of this structure wa' to prevent movement of larger organisms into the canal, thereby reducing the rumoer of organisms im-pinged at the plant. A set of removable 9.4-mm mesh screens extend through the water column in each of the 14 bays formed by reinforced con.

crete pilings and sheet pilingc. The screens were constructed of a 90/10 copper-nickel alloy to prevent the attachment of biofouling organisms, I thereby allowing for the free passage of cooling water.

Catches at stations sampled by the nekton program were compared to catches in the intake canal to determine the effectiveness of the riiversion structure in reducing the number and size of organisms entering the intake canal. Impingement data collected before and after the comple.

tion of the diversion structure were examined to ascertain whether there has been a corresponding reduction in the number and size of organisms im-pinged.

I I 25

I .

Results of these studies showed that catches of spot, Croaker, and menhaden were signiflCantly loner inside than outside the intake canal during 1984 (Table 17). Prior to the completion of the diversion struc-ture, nekton catches of these species inside the intake canal exceeded or equaled catches outside (Schwartz et al. 1979a; CP&L 1980c, 1982, and 1983). This was due to movement of juvenile spot, croaker, and menhaden

!l into the canal and their subsequent residence there for a growing season I (Birkhead et al. 1979). The decline in the nekten catch of spot, croaker, and menhaden (F igures 20, 21, and 22, respectively) was significant at

! stations inside the intake canal for 1981 through 1984. Similar analyses of catches at the nekton river stations showed stable or increasing trends, thus demonstrating the effectiveness of the diversion structure in excluding larger organisms from the intake canal.

! A significant reduction in the size of organisms prescnt in the in- ,

j take canal was also evident in the 1984 nekton catch (CP&L 1985). The l diversion structure excluded spot and croaker above 40 to 45 mm in length resulting in smaller fish in the intake canal as compared to outside (fig-l ures 23 and 24).

! The fish diversion structure is successful in preventing the migra-l_ tion of larger organisms into the intake canal. The 1977 through 1982 l impingement average was 636 kg per million cubic meters of water I entrained. This was reduced to 210 kg per million cubic reters in 1984--a l 67% reduction (Section 7). The fish diversion structure is also bere-j' ficial in reducing the chance of impingement of large numbers of schooling fish, such as menhaden, which Could substantially reduce the amount of

} cooling water available to the plant, resulting in costly plant load re-

I ductions or downtime.

i 9.0 SURVIVAL STUDIES i Recent intake modifications provided a mechanism for returning im-i pinged organisms to the estuary alive. Survival studies were initiated in

! early 1984 to determine what percentage of these impinged organisms were

{ returned alive. Emphasis was placed on commercially and/or recreationally

{ important species that were dominant in either tne larval or juvenile /

! adult impingement programs.

I 4

g Organisms impinged on the continuously rotating screens were washed into a sluice. The rotation of the screens could be set at two different rates--the f aster setting being approximately four times f aster than the I slower setting. A collection table was used to collect larval organisms h

f rom the sluice. The use of this device allowed for a longer sampling f duration, while reducing the mortality associated with collection (McGroddy and Wyman 1977). The larger juvenile and adult organisms were l

] collected with a 9.5-mm mesh net fitted on a frame that conformed to the l

shape of the sluice. Sampling was limited to three minutes to reduce l collection mortality associated with this gear. Control samples were collected from the intake canal using various types of nets and trawls to estimate mortality associated with the collection and holding of organ-isms.

a I Organisms collected for survival studies were quickly taken to the

[

1 g laboratory, sorted by species, and held for 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br />. Replicate tanks

, B were stocked with at least 30 organisms when available. Organisms were monitored hourly during the 96-hour holding period. Dead organisms were counted, measured, and removed; and water quality was checked. Water was pumped from the intake canal to a holding tank that allowed for a contin-  ;

uous flow of water to the aquariums at a rate of 0.95 liter / minute for the l

i 90-liter aquariums and 11.37 liters / minute for the 890-liter aquariums.

At the end of the 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br />, the number of live organisms in each tank was recorded. From this information, the initial and latent mortalities were obtained. Initial mortality refers to all organisms that died before i

I- reaching the laboratory, while latent mortality refers to those that died

,g during the 96-hour holding period. The percent total mortality and sur-

[5 vival were then calculated as follows:

I initial Mortalltf + Latent Mortality l Percent Total Mortality - -- x 100 Number of Organisms Collected Percent Survival = 100 - Percent Totai Mcrtality I

27

l A certain percentage of the organisms died due to f actors other than being impinged (i.e., holding mor tality, natural mortality, etc.). No g adjustment was made for this mortality

• therefore, the survival values 3 reported are conservative (Table 18). The mortality associated with col-lection and holding is represented by the percentages obtained for control organisms (Table 19).

The ability of organisms to survive impingement varied by species and size (CPT.L 1985). All life stages and sizes of penacid shrimp and blue crab examined showed consistently high survival (69% to 90%), whereas fragilt species such as menhaden and bay anchovy showed low or no survival (Table 18). lhis is not surprising considering Stickney's (1983) state-ment that the mere removal of the bay anchovy frrm the water caused "almost instant mortality." Croaker and spot survival increased with I increasing size and . sere improved with the f ast speed of rotation of tr,e screens. Overall, large croaker ( 25 mm) had a 36% survival for bcth f ast and slow screen rotation. Small croaker (< 25 mm) showed approxi-mately 29% survival during f ast speed but only 10% during slow speed.

Survival of spot was similar to that of croaker. The commercially impor-tant flounder and striped mullet, along with the abundant tonguefish and searobin, had excellent survival (Table 18).

Survival studies indicate that substantial numbers of impinged orga-nisms are returned to the estuary alive. Numerous commercially /

recreationally important species. including most shellfish species, were I shown to be minimally, if at all, c'fected by impingement and the subse-quent return processes.

10.0

SUMMARY

I For the last 11 years, the plant has been withdrawing water f rom the estuary. During this ll-year period, extensive environmental studies have been conducted to determine if the plant's withdrawal of water from the estuary was adversely affecting fish and shellfish populations. The re-suits of these studies indicate that the operation of the plant has not adversely affected the fisheries ir the estuary in any measurable way.

I 28

I The biological studies show:

1. The estuary is a stratified, two-layered estuarine system with a typical f reshwater/ salt-wedge interf ace. This is particularly true above the river constriction at Sunny Point where a salin-ity gradient exists which is modified by freshwater inflow and tidal flows.

I 2. There is a seasonal movement into, an associated residence time, I and a movement out of the estuary by ocean-spanned species of fish and shellfish. There is no evidence that this mechanism has been impacted by the operation of the plant.

3. The abundance, size, distribution, and dominance of larvae in the estuary have not changed in the past ten years, j 4. The discrete depth sampling program verifies that vertical dis-tributions and diel (day / night) behavior of larvae are the same as reported in past studies and that mean densities calculated from surface and bottom samples are not statistically different than means calculated from discrete depth sampling. Therefore, the reduction in the scope of the larval fish program in 1980

g did not reduce our ability to detect changes in larval / post-i5 larval population 3.

5. The similarity in concentrations of larvae and postlarvae in Dutchman Creek (a control creek not influenced by the plant) and Walden Creek (located near the plant) indicates that there has been no depletion of larvae in Walden Creek despite its close l proximity to the intake canal. in fact, the two creeks are not significantly different in their nursery f unctions.

[ 6. The marsh study indicates that the primary nursery areas are still being used to capacity today and that recruitment, sea-I sonality, and abundances of postlarvae and juveniles in those areas are uninterrupted by the operation of the plant.

29

7. The abundances of nektonic (free-swimming) organisms have not p significantly changed. The distribution of these organisms is t

related to, spatial and environmental variables and not to the operation of the plant.

8. Dominant species and the seasonal abundances of entrained organ-isms mimics those of the river larval fish program.

9. Special studies show that entrainment is reduced by about 82%

when fine. mesh screens are compared to 9.4-mm screens. Flow minimization results in a 26.5% to 47.4% entrainment reduction, yielding a calculated reduction of 90% when both measures are employed during the cooler portion of the year. This period corresponds to a time when a preponderance of commercially important species are entrained, thus giving an additive reduction during this critical period.

10. Though greatly reduced, some entrainment of larvae still occurs, but the populations in the estuarine nurseries have not been af-fected.

11. Impingement of large organisms-has been reduced due to the fish diversion structure. The construction and operation of the fish diversion structure prevent the movement of larger organisms into-the intake canal with a resultant _67% decrease in Weight of impinged organisms.

12. The use of fine mesh on the traveling screens reduced the size of organisms impinged but the number of organisms impinged in-creased.

13. Because of the diversion structure, juvenile and adult impinge-ment losses now occur _ from a greatly reduced population of available organisms. Reduction in the cropping rate of these larger individuals is especially ' vortant_ since, having survived life stages with high nate , mortality rates, they are more'likely to contribute to the species propagation.

30

I I 14 Survival studies indicate that there is a substantial return of live organisms to the estuary. Menhaden, a fragile species, I show a low percent of survival. The survival is approximately 90% for blue crabs and shrimp and 35% for spot and croaker.

The findings of these studies show that the mechanisms that operate within the estuary to deliver larvar spawned of f shore to primary nursery areas are unaf fected. The species composition, abundance, size, and sea-sonality of the organisms are unchanged. Additionally, the intake modifi-cations have substantially reduced impingement of larger organisms e.nd g increased survival of the smaller organisms that are impinged.

Table 20 shows the calculated reduction in cropping of I larval /postlarval organisms which can be attributed to the use of fine-mesh screens, flow minimization, and the combined effect of both modifica-tions. An average 32% reduction, due to survival or organisms impinged and returned to the estuary alive and a 37% overall reduction of organisms due to reduced flow, results in an overall 57% reduction in the number of larval /postlarval organisms cropped by the plant for both fine mesh and flow minimization.

in conclusion, CP'.L believes that the continued operation of the BSEP with the present modifications shows no measurable adverse impact on the Cape Fear Estuary.

I I

I I

8 31

11.0 SUPPORTING DOCUMENTS This Interpretive Report summarizes the results of 15 years of bio-I logical, hydrological, and thermal studies of North Carolina's Cape fear Estuary and modifications to the BSEP intake canal to reduce entrainment and impingement losses. The following list contains both literature cited in this text and supporting documents concerning these issues.

Birkhead W. S. 1977 Utilization of selected nursery areas of the Cape I fear Estuary, NC.

pany. North Carolina State University Raleigh, NC.

Report No. 77-6 to Carolina Power & Light Com-3 Birkhead, W. S., C. R. Bennett, E. C. Pendleton, and B. J. Copeland.

g 1977. Nursery utilization of the Dutchman Creek estuary, North Caro-lina, 1971-1976. Report No. 77-2 to Carolina Power & Light Company.

North Carolina State University, Raleigh, NC.

Birkhead, W. S. , B. J. Copeland, and R. G. Hodsen. 1979. Ecological monitoring in the loner Cape Fear Estuary, 1971-1976. BSEP Cape Fear I Studies, Volume V1. Report 79-1 to Carolina Power & Light Company.

North Carolina State University, Raleigh, NC.

I Birkhead W. S.,R. G. Hodson, and J. M. Miller.

entrainment of organisms in an estuarine power plant. Pages 32-53 in Report on entrainment and entrainment mortality of ooplankton and 1975. Variability of larvae and impingement and movement of fish. North Carolina State I University, Raleigh, NC.

Brandes, R. J., and F. D. Masch. 1974. Dye studies of the cooling water circulation system, Brunswick Steam Electric Plant. Report to Caro-lina Power & Light Company. Water Resources Engineers, Austin, TX.

Brinsfield, E. C., and M. T. Huish. 1980. Factors influencing the re-sponses of , juvenile spot. Atlantic menhaden and white mullet in a test fiume. Report No. 30-5 to Carolina Power & Light Campany.

I North Carolina State University, Raleigh, NC.

Brunswick Steam Electr.: Plant, impingement studies, Jan-I CP&L. 1975a.

uary 19, 1974-January 18, 1975. Carolina Pawer & Light Company, Raleigh, NC.

. 1975b. Brunswick Steam Electric Plant intake velocity pro-file study. Carolina Power & Light Company, Raleigh, NC.

. 1975c. A one-year report on the ecological monitoring of the borrow pit and freshwater drainage canal at Brunswick Steam Electric I Plant, Southport, North Carolina, May 1974-July 1975. Carolina Power

& Light Company, Raleigh, NC.

I

\E

I . 1975d, Proposal regarding reevaluatior, of need for cooling towers to minimize entrairment and impingement effects at the Bruns-wick Steam Electric Plant in light of biological monitoring frem I January 1974 through January 1975.

Raleigh, NC.

Carolina Power & Light Company, g . 1975e. Carolina Power & Light Company summary of technical data relating to environmental impact of cooling water intake system Brunswick Steam Electric Plant. Carolina Power & Light Company, l Raleigh, NC.

. 1977. A final report on the ecological monitoring of the borrow pit and freshwater drainage canal at Brunswick Steam Electric Plant, Southport, North Carolina. Carolina Power & Light Company, Raleigh, NC.

.I . 1979a. Intake canal tide monitoring at the BSEP, February 20, 1975-August 8, 1978. BSEP Cape Fear Studies, Volume II. Carolin: Power & Light Company, New Hill, NC.

. 1979b. kater chemistry report, Brunswick Steam Electric I Plant, 1972-1978. BSEP Cape Fear Studies, Volume III. Carolina Power & Light Comp.by, New Hill, NC.

. 1979c. tcan thermal plume studies at the Brunswick Steam Electric Plant, Southport, North Carolina, 1975-1978. BSEP Cape Fear-

[g Studies, Volume IV. Carolina Power & Light Company, New Hill, NC.

Ia

. 1979d. Brunswick Steam Electric Plant, ocean larval fish, November li'6-August 1978. BSEP Cape Fear Studies, Volume V. Caro-

_I lina Power & Light Company, New Hill, NC.

g . 1979e. Special river Tucker trawl study. Addendum I to BSEP 5 Cape Fear Studies, Volume V. Carolina Power & Light Ccmpany, New Hill, NC.

, . 1979f. Impingement studies at the Brunswick Steam Electric Plant, Southport, North Carolina, 1974-1978. BSEP Cape Fear Studies, Volume XVII. Carolina Power & Light Company, New Hill, NC.

. 1979g. Fluw mir.imization and mitigation report, Brurswick i Steam Electric Plant, Southport,. IlC.

XVIII.

BSEP Cape Fn.r Studies, Volume Carolina Power & Light Cumpany, Raleigh, NC.

I . 1979h. 316(a) demonstration, Brunswick Stean Electric Plant, Southport, NC. BSEP Cape Fear Studies, Volume XIX.

Light Company, New Hill, NC.

Carolina Power &

I 33

H L

_ _. 1980a. Brunswick Steam Electric Plant, Cape har Studies Interpretive Report. Carolin; Power & Light Company, New Hill, NC.

. 1980b. Brunswick Steam Electric Plant, Cape fear Studies Interpretive Report, executive summary. Carolina Power & Light Com-pany, New Hill, NC.

1980c, 1979 monitoring program. Supplement I to the 95EP Cape Fear Studies. Carolina Power & Light Company, New Hill, NC.

. 1980d. 1979 BSEP intake canal shoaling report and discharge Canal bathyma.tric survey, Carolina Power & Light Company, Raleigh, NC.

. 1982. Brunswick Steam Electric Plant 1981 annual biological monitoring repor t. Volumes 1 and 11. Carolina Power & Light Com-pany, New Hill, NC.

. 1983. Brunswick Steam Electric Plant 1982 biological moni-toring report. Volumes I and II. Carolina Power & Light s Spany, New Hill, NC.

I

_ _ , _ _ . 1984 Brunswick Steam Electric Plant 1983 biological moni.

toring repert. Carolina Power & Light Company, New Hill, NC.

I . 1985. Brunswick Steam Electric Plant 1984 biological moni-toring report. Carolira Power & Light Company, New Hill, NC.

Carpenter, J. H. 1968. Disposal cf waste heat, Brunswick Steam Electric Plant, Carolina Power & Light Company: Interim Report. Report to 8- Carolina Power & Light Company. Pritchard-Carpenter Consultants, Ellicott City M0.

. 19 F.9 5. Comrc.ents on the proposed circulating water system, l Brunswick Steam Electric Plant, Caroline Power & Light Company.

Report to. Carolina Power & Light Company. Ellicott City, MD.

l . 1969b. Additional comments on the proposed circulating water system, Brunswick Steam Electric Plant Carolina Power & Light Com-I pany. Report to Carolina Power & Light Company. Ellicott City, MD.

.g Carpenter, J. H. , and W. L. Yonts. 1979. Dye tracer and current meter 5 studies Cape fear Estuary, NC, 1976, 1977, and 1978. BSEP Cape Fear Studies. Report to Carolina Power & Light Company. Miami, FL.

l 4 Copeland, B. J. 1975. Report on entrainment and entrainment mortality of zooplankton and larvae and impingement and movement of fish. Report to Carolina Power & Light Company. North Carolina State University, Raleigh, NC.

34

L g Copeland, B. J., and W. S. Birkhead. 1972. Some ecological studies of the lo.er Cape Fear River estuary, ocean outfall and Dutchman Creek, 1971. First annual report to Carolina Poner & Light Company, North Carolina State University, Raleigh, NC,

. 1973a. Outchman Creek estuary, NC, as a nursery area. 1972 annual report to Carolinc Power & Light Company. North Ca,*olina State University, Raleigh, NC.

l . 1973b. Baseline ecology of the lower Cape Fest River estuary and ocean of f Oak Island, North Carolina, 1971-1972. Second annual report to Carolina Power & Light Company. North Carolina State University, Raleigh, NC.

I Copeland, B. J. , W. S. Birkhead, and R. G. Hodson.

sampling of the Brunswick Power Plant intake area and discharge 1974a. Intensive canal, January-March 1974 First interim report to Carolina Power &

Light Company. North Carolina State University, Raleigh, NC.

1974b. Intensive sampling of the Brunswick Power Plant I

intake area and discharge canal, January-September 1974. Second interim report to Carolina Power & Light Company. North Carolina State University, Raleigh, NC.

. 1974c. Ecological monitoring in the area of Brunswick Nuclear Power Plant, 1971-1973. Report to Carolina Power & Light Company. North Carolina State University, Raleigh, NC.

Copeland, B. J. , and R. G. Hodson. 1977. Larvae and postlarvae in the Cape Fear Estuary, North Carolina, 1976-1977. Report No. 77-5 to Carolina Power & Light Company. Nortn Carolina State University, .

Raleigh, NC.

Copeland, B. J., R. G. Hodson, and W. S. Birkhead. 1975. Entrainment and entrainment mortality at the Brunswick Nuclear Power Plant. Pages 1-31 in Report on entrainment and entrainment mortality of zooplankton and larvae and impingement and movement of fish. North Carolina State University, Raleigh, NC.

Copeland, B. J., R. G. Hodson, and R. J. Monroe. 1979. Larvae and post-larvae in the Cape fear River estuary, NC, during operation of the Brunswick Steam Electric Plant, 1974-1978. BSEP Cape fear Studies, Volume VII. Report No. 79-3 to Carolina Power & Light Company.

North Carolina State University, Raleigh, NC.

I I Copeland, B. J. , J. M. Miller, W. Watson, R. G. Hodson, W. S. Birkhead, and J. Schneider. 1976. Meroplankton: Problems of sampling and analysis of entrainment. Pages 119-137 in L. D. Jensen. (ed.) Third I national workshop on entrainment and impingement. Ecological Ana-lysts, Inc., Melville, NY.

I Dahlberg, M. D.1979. A review of survival rates of fish eggs and larvae in relation to impact assessment. U.S. Nat. Mar. Fish. Serv.

Mdr. Fish. Rev. 41:1-12.

Do11of f, C. A. , and M. T. Huish. 1980. Immersion staining and fluores.

cent pigment spraying of juvenile fish: An analysis of some factors influencing the success of these marking techniques. Report 80-1 to Carolina Power & Light Company. North Carolina State University, Raleigh, NC.

I Englert, T. L., H. Y. Chen, T. B. Vanderbeek, and J. P. Lawler. 1978.

Modeling of fish populations in the Cape Fear Estuary In: Proceeding of the Summer Computer Simulation Conference, Toronto, Ontario.

,g Geogtan, J. P. , and M. T. Huish. 1980. Distribution and diversity of

!g fish and crustacean communities in the Cape Fear River estuary, North Carolina, 1977-1979. Report No. 80-4 to Carolina Power & Light Company. North Carolina State University, Raleigh, NC.

Hartwell, S. I., and D. E. Hoss. 1979. Thermal shock resistance of spot Lafostomus ranthurus af ter acclimation to constant or cycling tempera-I ttre. Trans. Am. Fish. Soc. 108(4): 397-400.

I Hartwell, S. I. , and M. T. Huish.

juvenile spot, Leiostomus santhurus.

1977. The effect of cycling acclima-tion temperature on the thermal shock resistance of postlarval and Report to Carolina Power & Light Company. North Carolina State University, Raleigh, NC.

Hobbie, C. E. 1971. Some ecological measurements of the Cape Fear River.

Final report to Carolina Power & Light Company. North Carolina State I University, Raleigh, NC.

Hodsun, R. G. 1979. Utilization of marsh habitats as primary nursery I areas by young fish and sht imp, Cape Fear Estuary, North Carolina.

BSEP Cape Fear Studies, Volume VI!!. Report to Carolina Power &

Light Company. North Carolina State University, Raleigh, NC.

Hodson, R. G. , C. R. Bennett, and R. J. Monroe. 1981. Ichthyoplankton samplers for s1multaneous replicate samples at surf ace and bottom.

Estuaries 4(3):176-184 I

I

Hodson, R. G., and W. S. Birkhead. 1979. Seasonality, movements and J abundance of fish and shellfish in tidal creek habitats of the Cape l

Fear Estuary, North Carolina. BSEP Cape Fear Studies, Appendix A of Volume Vill. Report to Carolina Power & Light Company. North Carolina State University, Raleigh, NC.

Hodson, R. G. , and W. L. Conn. 1977 Ecological studies of larvae and postlarvae in the borrow pit adjacent to the BSEP dredged freshwater drainage canal, May 1974-December 1976. Peport to Carolina Power &

Light Company. North Carolina State University, Raleigh, NC.

, Hodson, R. G., R. G. Fechhelm, and R. J. Monroe. 1979. Temperature tole-rance of spot, Letostornus xanthurus, in the Cape Fear River estuary, NC. BSEP Cape Fear Studies, Volume XII. Report to Carolina Poner &

Light Company. North Carolina State University, Raleigh, NC.

. 1981. Upper temperature tolerance of spot, Leiostomus from the Cape Fear River estuary, North Carolina.

I ranthurus, Estuaries 4(4): 345-356.

Hodson, R. G., J. O. Hackman, and C. R. Bennett. 1981. Food habits of I young spots in nurscry areas of the Cape Fear River estuary, North Carolina. Trans. Am. Fish. Soc. 110:495-501.

Hodson, R. G., and D. Ruple. 1975. Larvae and postlarvae. Pages 31-53 in A one-year report on the ecoloolcci monitoring of the borrow pit g and freshwater drainage canal at Brunswick Steam Electric Plant, 5 Southport, North Carolina, May 1974-July 1975. Carolina Power &

Light Company, Raleigh, NC.

Hodson, R. G., J. W. Schneider, and B. J. Copeland. 1977. Assessment of entrainment during one unit operation of the Brunswick Steam Electric I Pl ant , 1974-1976.

Carolina State University, Raleigh, NC.

Report to Carolina Power & Light Company. North I Hogarth, W. T., and K. L. Nichols.

intake modifications to reduce entrainment and impingement losses.

1981. Cranswick Steam Electric Plant Carolina Power & Light Company, New Hill, NC.

Huish, M. T., and C. Benedict. 1976. Studies of sonically tagged fish in the lower Cape Fear River. Report to Carolina Power & Light Com-pany. North Carolina State University, Raleigh, NC.

. 1977. Sonic tracking of dusky sharks in the Cape fear River, North Carolina. J. Elisha Mitchell Sci. Soc. 93(1):21-26.

1980 (Abstr.). Sonic tracking of Atlantic sturgeon and white catfish in the lower Cape Fear River, North Carolina. 77th Annual Meeting, N.C. Academy of Sciences, Greenville, NC.

37

I I Huish, M. T., C. Benedict, and T. Johnson. 1975. Preliminary report of species. Sizes and iipingement rates of fish in anr near the Carolina Power & Light Company intake canal, Brunswick, Pages 54-89 in Report on entrainment and entrainment mortality of rooplankton and larvae and impingement and movement of fish. North Carolina State University, Raleigh, NC.

Huish, M. T. , and J. P. Geoghan. 1979. A study of addt and juvenile fishes of the lower Cape Fear River near the Brunswick Steam Electric Plant, 1975-1976. BSEP Cape Fear Studies, Volume XI!!. Report to Carolina Power & Light Company, North Caroline State University, I Raleigh, NC.

Kjelson, M. A. , G. N. Johnson, R. Lg Garner, and R. Bell. 1974. Esti-mated biomass for nekton communities and populations in the Newport River estuary and an evaluation of nekton sampling methods In: Annual report to Atomic Energy Commission by Atlantic Estuarine Fisheries I Center, National Marine fisheries Service, Beaufort, NC.

Laney, R. W. , and B. J. Copeland. 1981. Population dynamics of penacid I shrimp in two North Carolina tidal creeks.

& Light Company. North Carolina State University, Raleigh, NC.

Report to Carolina Power Lawler, J. P. , H. Y. Chen. T. L. Englert, and T. B. Vander ',eck. 1980.

Mathematical modeling of biological impact on the Ca: Fear Estuary I due to operation of the Brunswick Steam Elect-;c Plant.

fear Studies, Volume XX, Report to Carolina Power & Light Company.

Lawler, Matusky & Skelly Engineers, Pearl River, NY.

BSEP Cape

! Lawler, J. P., W. T. Hogarth, B. J. Copeland, M. P. Weinstein, R. G. Hod-son, and H. Y. Chen. 1980. Techniques for assessing the impact of I entrainment and impingement as applied to the Brunswick Steam Elec-tric Plant. Pages 159-182 6. Proceeding of the Fifth National Work-shop on Entrainment and Impingement, San Francisco, CA.

LMS. 1980. An analysis of mechanisms which govern persistence of popula-tions in the Cape Fear Estuary. BSEP hpe Fear Studies, Volume XVI.

I Report to Carolina Power & Light Company. Lawler, Matusky & Skelly Engineers, Pearl River, NY.

I MacPherson, K. A.

tric Plant, 1975-1976.

1977. Impingement studies at the Brunswick Steam Elec-Carolira Power & Light Company, Raleigh, NC.

MacPherson, K. A., R. W. Laney, and W. S. Birkhead. 1976. Amended shrimp tagging studies in the Cape Fear River. Carolina Power & Light Com-pany, Raleigh, NC.

t '8

)

. 1977. Shrimp tagging studies in the Cape fear River.

Carolina Power t. Light Company, Raleigh, NC.

Marshall, H. L. 1976. Effects of mosquito control ditching on Juncus marshes and utilization of mosquito control ditches by estuarine fishes and invertebrates. Ph.D. Thesis, University of North

] Carolina, Chapel Hill, NC.

McGroddy, P. M., and R. L. Wyman. 1977. Efficiency of nets and new de-vice for sampling living fish larvae. J. Fish. Res. Board Can.

.I 34: 571-574.

McHugh, J. L. 1967. Estuarine nekton. Pages 581-670 in G. H. Lauff (ed). Estuaries. Am. Assoc. Ad. Sci. No. 83. Washington, DC.

Pendleton, E. C. , and B. J. Copeland. 1979. Tidal import and export of organic detritus and organisms in a North Carolina salt marsh creek system. Report to Cerolina Power & Light Company. North Carolina I State University, Raleigh, NC.

Perschbacher, P. W., and F. J. Schwartz. 1917. (Abstra.c). Composition I and biomass of demersal fishes associated with silty-clay and sandy-loam estuarine substrates. ASB Bull. 24(2):76.

Pietrafesa, L. J., P. Blankinship, and R. D'Amato. 1977. Thermal efflu-ent transport pathways in coastal waters near the mouth of the Cape fear River estuary. Volume I: Data Report. Report to Carolina I Power & Light Company. North Carolina State University, Raleigh, NC.

Pietrafesa L. J., and M. Purba. Hydrodynamics of the Cape fear River.

I Manuscript in preparation.

I Purvis, C.

utaries.

1976. Nursery area survey of northern Pamlico Sound and trib-N.C. Division of Marine Fisheries, Morehead City, NC.

I Ross, S. W. 1978.

in North Carolina waters.

The life history of the banded drum, Larimus fasciatus, Sciences, University of North Carolina, Morehead City, NC.

(Masters Thesis) Institute of Marine

. 1984. Reproduction of the t,anded drum. Larimus fasciatus, in North Carolina. Fish. Bull. 82:227-235.

Rulifson, R. A. 1977. Temperature and water velocity effects on the swimming performance of young-of-the-year striped mullet (Mugfl cepha-lus), spot (Lelostomus ranthurus) and pinfish (Lagodon rhomboides). J.

Fish. Res. Board Can. 34(12):2316-2322.

I E

. 1981. Substrate preferences of juvenile penacid shrimps in estuarine habitats. Contrib. Mar. Sci. 24: 35-52.

L

. 1983. Behavioral aspects of juvenile penaeid shrimps, P.

aztecus and P. duorarum, during tidal transport. Contrib. Mar. Sci.

26:55-63.

p Rulif son, R. A. , and B. J. Copeland. 1980. Assessing the vulnerability L of penaeid shrimp to impingement on the traveling screens of the Brunswick Steam Electric Plant near Southport North Carolina. Re-port to Carolina Power f. Light Company, North Carolina State Univer-sity, Raleigh, NC.

I . 1982. Traveling screens as sampling gear for vertical distribution studies. Estuaries 5(2):B?-94.

Rulifson, R. A., and M. T. Huish. 1975. Temperature and current velocity effects on juvenile striped mullet, spot and pinfish swimming per-I formances. Report to Carolina Power f, Light Company.

State University, Raleigh, NC.

North Carolina Schnieder, J. W., B. J, Copeland, and R. J. I onroe. 1980. The vertical distribution of estuarine meroplankton in the vicinity of a power plant cooling water intake, Southport, North Carolina.

I Carolina Power & Light Company.

Raleigh, NC.

Report to North Carolina State University, Schwartz, F. J. 1974 An ecological study in the vicinity of the Bruns-wick Power Plant of the fishes utilizing the lower Cape Fear River and adjacent ocean. A partial report for the period February through I

l May 1973. Institute of Marine Sciences, University of North Caro-lina, Morehead City, NC.

. 1977. Evaluation of colored Floy anchor tags on white shrimp, Penaeus setiferus, tagged in the Cape Fear River, North Caro-lina, 1973-1975. Fla. Sci. 40(1):22-27.

Schwartz, F. J., R. Clayton, D. Fast, and F. Rohde. 1975. An ecological study, in the vicinity of the Brunswick Power Plant, of the fishes, crabs, shrimps utilizing the lower Cape Fear River, Carolina Beach inlet, and adjacent ocean cape: A partial report for the period 23 July 1973, through 30 May 1974. Institute of Marine Sciences, Uni..

versity of North Carolina, Morehead City, NC.

Schwartz, F. J. , and M. D. Dahlberg. 1978. Biology and ecology of the Atlantic stingray Dasyatis sabina (Pisces:Dasyatidae), in North Caro-lina and Georgia. Northeast Gulf Sci. 2(1):1-23, 40

Schwartz, F. W. T. Hogarth, and M. P. Weinstein.

I J.,

freshwater fishes of the Cape Fear Estuary, North Carolina, and their distribution in relation to environmental f actors.

1981. Marine and Brimleyana 7: 17-37.

I Schwartz, F. J., and P. A. Howland. 1978. Literature evaluating gear and factors af fecting catch and sampling variation. Special scientific I report. Institute of Marine Sciences, University of North Carolina, Morehead City, NC.

I Schwartz, F. J., P. Perschbacher, K. Sulak, D. Mason, W. Link, J. Vorhees, and K. Sandoy. 1977. An ecological study, in the vicinity of the Brunswick Pcwer Plant, of the fishes, crabs, shrimps utilizing the lower Cape Fear River, Carolina Beach inlet, and adjacent Atlantic 4'

I Ocean: A partial report for the year 1976.

Sciences, University of North Carolina, Morehead City, NC.

Institute of Marine Schwartz, F. J., P. Perschbacher, L. Davidson, C. Simpson, M. McAdams, K. Sandoy, J. Duncan, and O. Mason. 1979a. An ecological study of fishes and invertebrate merof auna utilizing the Cape Fear River I estuary, Carolina Beach Inlet, and adjacent Atlantic Ocean, 1973-1977. BSEP Cape Fear Studies, Volume XIV. Report to Carolina Power

& Light Company. Institute of Marine Sciences. University of North

!3 Carolina, Morehead City, NC.

'5 Schwartz, F. J., P. Perschbacher, J. Dickens, and M. McAdams. 1979b. An ecological study of fishes and invertebrate macrof auna utilizing the 4

^

Cvse Fear River estuary, Carolina Beach Inlet, and adjacent Atlantic Ocean, 1973. BSEP Cape Fear Studies, Volume XIVa. Report to Caro-lina Fower & Light Company. University of North Carolina, Morehead City, NC.

. 1979c. An ecological study of fishes and invertebrate macro-

, f auna utilizing the Cape Fear River estuary, Carolina Beach Inlet.

and adjacent Atlantic Ocean, 1974 BSEP Cape Fear Studies, Volume XIVb. Report to Carolina Power & Light Company. Institute of Marine Sciences, University of North Carolina, Morehead City, NC.

. 1979d. An ecological study of fishes and invertebrate macro-fauna utilizing the Cape fear River estuary, Carolina Beach Inlet, and adjacent Atlantic Ocean, 1975. BSEP Cape fear Studies, Volume XIVc. Report to Carolina Power & Light Company. Institute of Marine Sciences, University of North Carolina, Morehead City, NC.

. 1979e. An ecological study of fishes and invertebrate macro-fauna utilizing the Cape Fear River estuary, Carolina Beach inlet, and adjacent Atlantic Ocean, 1976. BSEP Cape Fear Studies, Volume XIVd. Report to Carolina Power & Light Company. Institute of Marine j Sciences, University of North Carolina, Morehead City, NC.

l 41

s I

. 1979f. An ecological study of fishes and invertebrate macro-f auna utilizing the Cape Fear River estuary, Carolina Beach inlet.

l and adjacent Atlantic Ocean, 1977 BSEP Cape Fear Studies, Volume XIVe. 'leport to Carolina Power & Light Company. Institute of Marine r Sciences, University of North Carolina, Morehead City, NC.

L Schwartz, F. J., P. Per.chbacher, L. Davidson, K. Sandoy, J. Tate.

- M. McAdams, C. Simpson, J. Duncan, and D. Mason. 1979g. An eco-logical study of fishes and invertebrate macrof auna utilizing the Cape Fear River estuary, Carolina Beach inlet, and adjacent Atlantic Ocean, 1978. BSEP Cape Fear Studies, Volume XV. Report to Carolina Power & Light Company. Institute of Marine Sciences. University of North Carolina, Morehead City, NC.

Schwartz, F. J. , J. Morgan, K. Sandoy, M. McAdams, and D. Meson. 1980.

Food analyses of selected fishes captured in Cape Fear Estuary and adjacent Atlantic Ocean, North Carolina, 1973-1978. Report to Caro-lina Power & Light Company. Institute of Marira Sciences University of North Caroline, Morehead City, NC.

Seneca, E. D., L. M. Stroud, and U. Blum. 1979. An analysis of the ef-fects of the Brunswick Nuclear Power Plant on the productivity of Spartina alterniflora (smc oth cordgrass) in the Dutchman Creek, Oak Island, Snow's Marsh, and Walden CreeX marshes, Brunswick County, North Carolina, 1977-1978. BSEP Cape Fear Studies, Volume XI. Fifth annual report to Carolina Power & Light Company. North Carolina State University, Raleigh, NC.

Shelton, S. T. 1979. The age, growth and food habits of the windowpane flounder, Scophthalmus aquosus (Mitchill) in the lower Cape Fear River estuary and adjacent ocean. (Masters Thesis) Institute of Marine Sciences, University of North Carolina, Morehead City, NC.

Stickney, R. R. 1983. Care and handling of live fish. Pages 85-04 in L. A. Nickison and D. L. Johnson (eds). Fisheries techniques.

American Fisheries Society, Blacksburg, VA.

Street, M. 1985. Status of the N.C. Commercial Catch. Tar Heel Cuast, Volume 20, No. 1. N.C. Divison of Marine f.;heries, Morehead City, NC.

Thayer, G. W. , D. R. Colby, M. A. Kjelson, and M. P. Weinstein. 1983.

Estimates of larval-fish abundance: Diurnal variation and influer.ces of sampling gear and towing speed. Trans. Am. Fish. Soc. 112:272-279.

42

I L

Tucker, J. W., Jr. 1982. Larval development of Citharichthys cornutus, C.

gymnorhinus, C. spilopterus, and Etropus crossotus (Bothidae), with notes

( on larval occurrence. Fish. Bull. 80(1):35-73.

Tucker, J. W., Jr., and R. G. Hodson. 1976. Early and mid-metamorphic larvae of the tarpon. Afegalops atlanticus, f rcm the Cape Fear River estuary, North Carolina, 1973-74 Chesapeake Sci. 17(2):123-125.

Vorhees, J. T., and F. J. Schwartz. 1979. Attachment site, seasonality, and effect of the parasitic copepod Lernacenicus radiatus on two estua-l rine fishes in the Cape Fear River, North Carolina. Trans. Am. Fish.

Soc. 108(2):191-196.

I Weinstein, M. P. 1979a. High marsh study, Cape Fear River, 1978. BSEP Cape Fear Studies, Volume IX. Report tc Carolina Power & Light Com-pany. Lawler, Matusky & Skelly E gineers, Pearl River, NY.

t

. 1979b. Larval retention study, Cape Fear River, 1978. BSEP l Cape Fear Studies, Volume X. Report to Carolina Power & Light Com-pany. Lawler, Matusky & Skelly Engineers, Pearl River, NY.

l . 1979c. Shallow marsh habitats as primary nurseries for fishes and shellfish, Cape Fear River, Ncrth Carolina. Fish. Bull.

77(2):339-357.

Weinstein, M. P., and R. W. Davis. 1980. Collection efficiency of seine and rotenone samples from tidal creeks, Cape Fear River, North Caro-lina. Estuaries 3(2):98-105.

Weinstein, M. P., and M. F. Walters. 1981. Growth, survival and produc-I tion in young-of-year population of Lelostomus ranthurus Lacepede residing in tidal creeks. Estuaries 4(3):185-197.

Weinstein, M. P., S. L. Weiss, R. G. Hod:.on, and L. R. Gerry. 1979.

Retention of three taxa of postlarval fishes in an intensively flushed tidal estuary, Cape Fear River, North Carolina. Fish. Bull.

I 78(2):419-436.

l5 Weinst.ein, M. P., S. L. Weiss, and M. E. Walters. 1980. Multiple deter-minants of community structure in shallow marsh habitats, Cape Feur River Estuary, North Carolina. Mar Biol. 58:226-243.

Williams, J. B. 1978. Prcductivity, population dynanics, and physiologi-cal ecology of the dwarf surf clam, Afulinfa lateralis, rear a power plant intake canal, Soethport, North Carolina. Report 7B-1 to Caro-lina Power & Light Company. (Doctoral Thesis) Noth Carolina State University. Raleigh, NC.

43

a I~

L Table 1 A summary of the BSEP biological studies program.

l Program Sampling frequency Sampling Locations l

3 E Entrainment We#1y Discharge weir I Survival Studies Dependent on organism availability Return fiume; Intake canal Impingement Juvenile and Adult Weekly Return fiume Larval Every two weeks Return fiume Water Quality Weekly Dutchman Creek; Walden I Creek; and seven river stations River Larval Fish Every two weeks from Dutchman Creek; Walden September to May and Creek; and five river monthly from June to stations August I

Discrete Depth February to March Buoys 19 and 38 (four 24-hour trips)

Nekten Every three weeks Walden Creek; Alligator Creek; ten river sta-tions; and three intake

.I Canal stations High Marsh Every three weeks Seven Baldhead Creek stations: nine Walden creek stations; two Mott's Creek bay sta-s tions; four Alligator Creek stations; and one return basin station I

I

<I

,I g o

M M M M M M M M M M M M M M M M M M W Table 2 Annual mean density (organisms /10003m ) and the percentage of the total mean density for the eight most abundant species collected in the river larval fish program, 1974-1984.

Species 1974a  % 1975a  % 1976a g ig77 b  % 1978b .c g Anchovy 289 64.9 247 45.2 396 58.7 622 56.0 97 16.2 Croaker 36 8.2 105 19.1 26 3.8 53 4.7 134 22.2 Portunid megalops . . . . 9 1.3 41 3.7 1" 23.0 Cobiosoma spp. 38 8.6 27 5.0 98 14.5 203 18.3 34 5.7 Spot 17 3.9 53 9.? 19 2.8 66 5.9 65 10,8 Penaeus spp. 3 0.7 34 6.2 32 4.8 26 2.3 15 2.5 Menhaden 8 1.9 7 1.2 4 0.6 28 2.5 SI 8.5 Silversides 2 0.3 2 0.3 9 1.4 7 0.6 6 1.0 Total 445 88.5 547 86.7 674 87.9 1112 94.0 600 89.9 Species 1979 d  % 1980 d  % 19818  % 1982 0  % 19830  % 1984 0  %

Anchovy 691 43.1 1937 63.6 581 34.6 733 35.7 614 41.6 578 47.5 Croaker 170 10.6 232 7.6 200 11.9 501 24.4 367 24.9 210 17.2 Portunid megalops 31 1.9 176 5.8 153 9.1 253 12.3 114 7.7 104 8.5 Gobiosoma spp. 36f, 22.8 359 11.8 421 25.1 197 9.6 65 4.4 71 5.8 Spot 82 5.1 76 2.5 80 4.7 129 6.3 71 4.8 63 5.2 Penaeus spp. 72 4.5 122 4.0 54 3.2 52 2.5 75 5.1 63 5.2 Menhaden 16 1.0 5 0.2 41 2.4 14 0.7 19 1.3 20 1.6 Silversides 59 3.7 16 0.5 26 1.5 16 0.8 6 0.4 11 0.9 Total 1502 92.7 3046 96.0 1679 92.5 2052 92.3 1475 90.2 121R 91.9 atto replicate sampling; intake area only; eight stations.

b tlorth Carolina State University intensive sampling; 25 stations.

cllo surrrner (June, July, and August) samples collected.

d Carolina Power & Light monitoring; night only; 7 stations.

eCarolina Power & Light monitoring; 7 stations; night only; once a month sr.mpling June, July, August.

I I Table 3 Results of time-series analysis for river larval fish data, 1977-1984, indicating significant changes (+- or -) in density along with amount of variance ext,lained by the model (Rd ) by station i group.

Station Group ,

11 24 18 + 25 + 37 34 + 41 Taxon (+/-) R 2

(+/-) R 2

(+/-) R 2 ( j,) p2 Anchovy iS 0.97 NS 0.97 (+)*** 0.98 (+)*** 0.96 l Croaker Flounder

(+)*** 0.91 NS 0.9

(+)*** 0.95 NS 0.87 NS NS 0.97 0.9

(+)*

NS 0.94 0.86 l Cobiosoma spp.

Gobionellus spp.

NS 0.94 NS

(+)*** 0.90 (+)***

0.94 0.90 NS 0.95 NS

(+)*** 0.86 (+)***

0.85 0.84 Menhaden NS 0.79 NS 0.81 N5 0.79 NS 0.79 Mullet NS 0.81 (+)** 0.82 NS 0.67 NS 0.61 Seatrout NS 0.86 NS 0.86 NS 0.86 NS 0.87

'I Spot NS 0.96 NS 0.98 NS 0.97 NS 0.92 Penaeus spp. (+)** 0.94 NS 0.95 (+)** 0.92 (+)*** 0.83 Total organisms (+)** 0.99 (+)** 0.99 (+)*** 0.995 (+)** 0,99 I

NS Not significant

• 0.01 < P 5 0.05

• • 0.001 < P 5 0.01

• • • P $ 0.001 NOTE: R 2 is an adjusted value.

-l.

I LI I

g 4e

L. -

Table 4 Results of analysis of variance comparing 1984 river larval fish density data [ loge (density + 1)] from Dutchman Creek and Walden Creek.

Duncan's Multiple Cell Means Species Station Range Test DC WC k Anchovy NS 2.40 2.45 Croaker NS 3.23 2.80

( Gobiosoma spp. NS 0.89 0.85 Spat ** 3.81 DC > WC 3.12 Brown shrimp

• DC > WC 3.02 2.53 Pink and white shrimp NS 4.74 4 89 Menhaden *** WC > DC 2.03 3.17 Total organisms NS 6.16 6.14 l NS Not significant DC = Dutchman Creek (Station 11)

• 0.01 < P 5 0.05 WC = Walden Creek (Station 24)

"0.001 < P 3 0.01

• • • P 5 0.001 1

I I

47

Table 5 Salinity preference of selected species collected by trawl and seine in the high marsh study from 1981 through 1984, L

, Species 1981 1982 1983 1984 l

Menhaden F-0 F-0 F-0 F-0 Spot F-0 F-0 F-0 F-0 Crosker F-0 F-0 F-0 F-0 Striped mullet F-0 F-0 F-0 F-0 Southern flounder F-0 F-0 F-0 F-0 I Blue crab F-0 F-0 F-0 F-0 White shrimp F-0 F-0 P F-0 I Mammichog M F-0 M "0 Brown shrimp M F-0 M F-0 Pink shrimp M M P F-0 Bay anchovy P P F-0 P Atlantic silverside M P P P White mullet M P P P F-0 (Fresh-011gohaline) = 0-8 ppt I M (Meschaline) = 8-16 ppt P (Polyhaline) = 16-30 ppt 48

Table 6 Catch-per-unit-effort by creek system for 12 selected species collected by trawl and seine in the high marsh study during 1984.

(

Baldhead Walden Mott's Bay Alligator Species Creek (Lower Creek (Mid- (Upper Creek (Upper Estuary) Estuary) Estuary) Estuary)

Spot 87 211 135 7 l Bay anchovy 35 12 156 10 Brown shrimp 13 36 3 0 Menhaden 7 29 42 5 l

Croaker 0 10 46 16 Blue crab 5 10 8 3 Striped mullet 6 70 5

• Mummichog 3 65 0

• Flounder 0 3 4 19 Pink shrimp 4 5 1 0 White mullet 25 12 0

• Atlantic silverside 30 2 2 *

• Seine samples were not collected in Alligator Creek.

I I

I I .

49

I I Table 7 Mean log g catch-per-unit-effort of total organisms collected by trawl in Baldhead Creek and Walden Creek in the high marsh study during 1984 1 I ,

l Baldhead Creek Station Downstream Upstream

. 11 12 13 14 15 16 17 Mean loge CPUE 3.76 3.61 3.82 4.15 4.64 4.52 5.24 Walden Creek

, Station 21 22 22 29 28 24 25 26 27 Mean loge CPUE 4.49 4.15 4.38 4.52 4.79 5.33 5.22 5.70 6.35 il 4

!I il

!I 4

lI

!I I

I I

'o lI

Table 8 Results of time-series analysis of high marsh data by creek showing significant trends in abundance from 1981 through 1984.

Alligator Creek Mott's Bay Walden Creek Baldhead Creek R2 R2 Trend R2 Species T rend R2 Trend Trend 0.97 (4)** 0.95 Spot (-)*** 0.86 (-)** 0.90 NS 0.78 0.77 NS 0.86 NS 0.75 Bay anchovy (-)* NS

(-)* 0.75 NS 0.91 (+)** 0.87 l 8rown shrimp ID 0.82 0.69 (-)* 0.96 (+)** 0.83 Menhaden (-)* NS 0.78 NS 0.81 (+)*** 0.88 (+)*** 0.59 Croaker NS 0.88 NS 0.87 NS 0.96 (4)*** 0.94 Crabs NS Striped mullet HA NS 0.59 (4)** 0.89 ID Mummichog NA ID NS 0.88 NS 0.89 flounder (+)*** 0.93 (+)** 0.78 (+)*** 0.87 10 0.85 (-)** 0.83 NS 0.89 (+)** 0.83 Pink shrimp NS 0.52 0.82 NS 0.94 White mullet NA (-)** NS Atlantic 0.84 silverside NA NS 0.58 NS 0.56 NS White shrimp ID (-)* 0.49 NS 0.88 ID NS Not significant (-) = decreasing trend

• 0.01 < P $ 0.05 (4) = increasing trend

• • 0.001 < P $ 0.01 ID = insufficent data

• • • P $ 0.001 NA = analysis is not applicable because seine hauls were not made.

2 is an adjusted value.

NOTE: R I _ _ _ ____. .

2 Table 9 Standing crop estimates (number /m ) Of selected Organisms collected in North River estuary, Jarrett Bay, and in the Cape fear Estuary. North Carolina, from 1977 through 1984.

Cape Fear Estuary j 1978 I 1977 North River Estuary (1971-77)* Jarrett Bay (1971-77)* Baldhe ad Walden Uprlwer Baldhead Walden tJeriver Creek Oltches Creek Marsh Marsh Marsh Mar sh Marsh Mar sh l Species Oltches Spot 1.4 1.5 1.0 0.2 0.7 7.0 t.2 1.5 3.8 0.7 Menhaden 0.3 -

0.4 -

0.04 0.5 1.10 0.1 13.5 1.4 Ffounders 0.06 - - -

0.02 0.02 0.05 0.04 0.1 0.5 Hay anchovy 0.3 0.05 - -

1.0 0.1 0.1 0.7 0.01 0.5 Orown shristp 0.4 0.04 0.09 -

0.03 0.3 0.3 0.1 0.6 0.0f Pink snrImp - -

0.06 0.06 0.07 0.03 0.06 0.08 < 0.01 < 0.0t White shrimp -

0.05 - - -

0.07 v 04 -

< 0.01 < 0.01 Hlue crao 0.1 0.5 0.7 0.3 0.07 0.06 0.06 0.07 0.1 0.8 W c N Cape Fear Estuary 1981 1997 1983 1954 Baldhead Walden Mott's Dafdhead Walden Mott's Baldhead Walden Mott's Beldhead Walden s+2t t 's Creek Bay Creek Creek Bay Creek Creek Bay Creek Crecta Bay Species Creek Spot 0.78 1.47 1.80 0.16 1.06 0.37 0.50 1.80 0.12 0.58 f.40 0.90 Menhaden 0.05 0.09 0 07 0.07 0.47 0.03 0.15 0.77 0.tt 0.05 0.19 0.75 Southern ffounder 0.00 0.00 0.00 0.00 0.01 0.03 0.00 0.01 0.01 0.00 0.07 0.03 03y anchovy 0.20 0.06 0.16 0.46 0.76 0.16 0.04 0.19 0.19 0.73 0.06 1.05 Brow , shrimp 0.01 0.10 0.07 0.08 0.11 0.07 0.06 0.19 0.07 0.09 0.74 0.07 Pink shrimp 0.01 0.03 0.07 0.01 0.03 0.05 0.nl 0.03 0.f7 0.03 0.03 0.0t White shrimp 0.00 0.00 0.01 0.01 0.03 0.05 0.00 0.05 0.00 0.0P 0.01 0.00 Blue crab -- -- --

0.00 0.01 0.01 0.05 0.09 0.09 0.03 0.01 0.05 Mar sha 1 i 1976 Cnitected by seise and votennne.

' Collected by t r ia l ,

] Table 10 Peak seasonal recruitment of selected species collected by

) trawls and seines in the high marsh study from 1981 through l 1984.

L I. Species 1981 1982 1983 1984 Menhaden Apr Mar May May Bay anchosy Aug-Sep Jul Aug Jul Mummichog

• Jul Jul Sep Atlantic silverside

• Aug Sep Jul Spot Mar Apr Apr Mar Croaker May Apr May Mar-May Striped mullet Mar Apr-May May Apr-May White mullet Jun Jul Jun Jul Flounder Feb Apr Apr Mar Brown shrimp Jun Jun Jun May Pink shrimp Aug Nov Nov Jul l

White shrimp Aug Aug Aug Jul Blue crab Feb Jan Feb May

• No data recorded.

I I

53

I Table 11 Annual catch-per-unit-ef fort (CPUE) by station of the dominant commercial species collected in the nekton study during 1984.

I Station Spot

• Croaker

• Menhaden

• Brow'n Shrimp Blue Crab I 5

$2 1 3.47 2.29 0.76 0.03 2.76 1.53 14.50 0.08 0.94 1.35 I E4 2.26 1.73 41.31 10.05 7.12 0 6 0.09 0.06 4.00 4.41 2.76 I 13 5

0.09 0.15 0.15 0.35 1.47 3.05 11.32 70.00 9.62 13.18 7 0.71 1.50 23.00 7.50 2.15 8 0.15 0.12 0.41 0.73 4.44 10 0.18 5.53 207.75 3.00 13.03 14 1.12 5.15 7.68 15.82 13.88 11 1.24 0.26 1.24 3.70 2.79 g 15 0.06 0.00 1.05 1.15 2.29 2 16 0.03 0.18 0.44 5.17 2.09 c:

$ 12 0.00 0.00 0.00 0.00 2.00

• Data is for juvenile / adult size class only.

I 3 Table 12 Reduction in entrainment mean density (number /1000 m) for l

I selected species for three special study periods (November 1984-January 1985).

Gobionellus Total Anchovy Croaker Spot spp. Organisms

.I l

9.4-mm screens 34 387 65 30 543 1-mm screens 10 45 27 9 99 Reduction 69% 88% 58% 70% 82%

1 54

, 3 g- ---

Table 13 Comparative reductions in entrainment of total organisms due to flow minimization.

Observed Historical Density flow Number / Day Flow Number / Day Percent Reduction ,

Time Period l 3

(f/1000 m ) (cy3)

January 1981-June 1983 1759 843 3.6 x 10 6 1149 4.9 x 10 6 26.5 July 1983-November 21, 1983 632 818 1.3 x 106 1185 1.8 x 10 6 27.8 November 22, 1983-Apr11 1984 a359 610 b5.4 x 105 1105 9.7 x 10 5 44,3 November 22, 1983-Apr11 1984 c1994 610 3.0 x 10 6 1105 d5.4 x 106 44,4 May 1984-October 29, 1984 705 884 1.5 x 106 1205 2.1 x 10 6 28.6 October 30, 1984-April 18, 1985 8 289 580 h4.1 x 105 1105 7.8 x 10 5 47,4 October 30, 1984-April 18, 1985 C 1606 580 2.3 x 10 6 1105 da.3 x 106 46.5 aAdjusted for fine mesh only.

bEstimated number of total organisms entrained / day.

C Calculated increase in entrainment without fine-mesh screens based on results of special study (Table 12).

dCalculated number that would have been entrained without fine mesh or flow minimizatfon.

NOTE: Difference between b and d is a 90% reduction in entrainment because of flow minimization and fine-mesh screens.

M M M M M M M M M M M M M M M M Table 14 Percent conrposition of entrainment density (number /1000 m3) fram 1975 through 1984.

1977 1978 1979 1980 1981 1982 1983 1984 1975 1976

(%) (%) (%) (%) (%) (%) (%)

Taxon (%) (%) (%)

36.8 48.1 49.2 41.4 33.8 30.3 28.5 34.1 29.0 24.7 Anchovy 0.8 5.0 0.9 1.1 0.5 0.3 1.0 1.6 0.8 1.4 Menhaden 3.3 4.0 1.4 0.9 1.0 0.5 0.3 0.9 0.4 0.2 Seatrout 9.5 8.5 11.6 9.7 14.0 14.3 6.3 16.6 13.8 16.9 Spot 22.4 7.9 2.1 11.8 9.7 13.3 4.2 17.0 24.1 17.8 l froaker 0.1 0.4 0.2 0.4 0.9 0.7 0.5 0.9 0.3 0.4 l Mullet Flounder 0.2 0.2 0.4 0.7 1.1 0.1 0.3 0.4 0.3 0.2 Goldo iclius spp. 1.6 0.9 1.4 0.5 0.8 0.8 0.7 2.2 2.4 1.9 Goldoscnur spp. 19.9 15.7 24.2 25.3 27.4 31.3 45.8 14.4 20.8 27.0 Mean density of 849.5 1064.8 1380.8 822.4 1067.4 1174.5 1779.7 1324.5 1314.4 548.5 total fish i -----_

ml ra r- 1 rT r Table 15 Estimated survival of juvenile and adult organisms impinged during 1984.

Number of Estimated Estimated Percenta Survival Number Weight (kg) tbmber Weight (kg)

Species Survival Tests Impinged Impinged Survived Survived 92.2 145,080 499 13I, M 460 Penaeus spp. (pink and white) 7 93.7 2 286,626 4,227 268,569 3,961 Blue crab 92.0 19,691 475 18,116 437 Striped mullet 1 Brown shrimp 86.5 4 83,662 878 72,368 759 B1ackcheek tonguefIsh 79.6 3 131,575 192 96,774 153 59.5 2 89,252 544 53,105 324 Spot 55.7 5 110,199 445 61,381 248 Croaker 35.0 20,790 67 7,277 23 Weakfish 1 15.6 1 653,960 5,186 102,018 839 Menhaden O 0.0 3,023,433 1,950 0 0 Bay anchovy 1 Atlantic silverside . . 203,697 585 . .

Other species (104 taxa) . . 370,852 1,842 . .

5,128,817 16,890 813,372 7,174 Total b 15.9% 42.5% E

% Survival Excluding bay anchovy 2,105,384 38.6%c Excluding bay anchovy and others not tested 1,530,835 53.1%d

.Not tested.

aPercent survival calculated using only juvenile and adult-size classes.

bPercent survival of total number of organisms impinged.

cPercent survival of total number of organisms impinged excluding bay anchovy.

dPercent survival of total number of organisms impinged excluding bay anchovy and others not tested.

ePercent of total weight of organisms impinged that survived.

Table 16 Overall percent survival and number of larval organisms impinged and returned alive to the Cape fear Estuary.

Overall Percent Survival Number Returned Alive Fast Slow Fast Slow Total Screen Screen Screen Screen Number impingeo Speed Speed Speed Speed Species Croaker 1.3 X 10 8 29.6 12.0 3.8 x 10 7 1.6 x 1 Spot 1.2 x 10 8 30.9 8.9 3.7 x 10 7 1.1 x 10 7 3.9 x 10 7 0 0 0 0 Bay anchovy ,

7 7 Penaeus postlarvae 3.2 x 10 7 90.2 77.1 2.9 x 10 2.5x 10 Flounder 2.7 x 10 6 90.0 . 2.4 x 10 6 ,

Mullet 1.6 x 10 6 67.7 . 1.1 x 10 6 ,

Portunid megalops 1.2 x 10 8 88.2 86.3 1.1 x 10 8 1.0 x 108 Weakfish 8.5 x 10 5 12.5 . 1.1 x 10 5 ,

Anchon spp. 5.7 x 10 I . . . .

Menhaden 1.6 x 10 7 , , , ,

Other organisms (89 taxa) 5.0 x 10 7 . . . .

Total organisms 5.7 x 10 0 Total organisms tested 4.5 x 108 (79g)a 2.2 x 108 (49%)c Total organisms tested ,

excluding bay anchovy 4.1 x 100 (72%)b 2.2 x 108 (54%)d

. Not tested.

aPercent of total organisms impinged that were tested.

bPercent of total organisms impinged that were tested excluding bay anchovy.

I cPercent of 8 that were returned alive.

d Percent of b that were returned alive.

I-Table 17 Results of analysis of variance and Duncan's multiple range te:t I for selected nekton species compering stations inside and out-side the BSEP diversion structure during 1984.

I Duncan's Muitiple Species ANOVA R 2 Source F-Value Range Test

.I Spot 0.88 Trip 2.82 NS I (juvenile / adult)

Station 30.50*** 4 5136 Trip

• Station 1.64 NS Croaker 0.74 Trip t "

I (juvenile / adult)

Station 1.21 NS 12.17*** 41365 Trip

• Station 1.64 NS Menhaden 0.89 Trip 20.35*** 13254 (juvenile / adult)

, Station 22.30*** 4 5 6 13 a Trip

• Station 1.81 NS Station 4 is located outside of the diversion structure and Stations 5, 6, and 13 are located inside of the diversion structure.

Underscores indicate similarity and values decrease from left to right.

NS Not significant

• 0.01 < P $ 0.05

• • 0.001 < P 5 0.01 l ***P 5 0.001 l .

I I

I 59

m m 'm m W W W W W W m W m W W M M M M Table 18 Survival percentages for organisms collected during fast and slow screen operation at the BSEP during 1984 and 1985.

Number Percent Taxon Screen of Number Number initial latent Total Collected Speed Trials Collected Stocked Mortality a Mortality b SurvivalC Croaker--Group 1 F 15 2903 1285 39.6 52.2 28.9

--Group 2 F 5 584 338 36.0 43.8 36.0 Spot--Group 1 F 8 1349 620 19.0 61.8 31.0 Pink and white shrimp F 6 264 219 1.4 5.5 92.7 Brown shrimp F 2 87 81 7.9 25.9 69.0 Penaeld postlarvae F 2 188 120 4.3 5.8 90.2 Blue crab F 4 170 79 2.4 5.1 92.7 Blue crab megalops F 2 159 71 1.9 1).3 88.9 Weakfish F 4 282 191 19.4 82.2 12.6 Searobin F 4 132 124 2.3 8.1 89.8 B1ackcheek tonguefIsh F 3 110 95 5. 5 15.8 79.6 Bay anchovy F 2 249 114 54.2 100.0 0.0 Striped mullet--Group 1 F 1 62 52 16.1 19.2 67.7

--Group 2 F 1 37 37 0.0 8.1 91.9 F lourder F 1 91 78 8.9 1.3 90.0 g Menhaden F 1 32 30 6.3 83.3 15.6 Croaker--Group 1 5 12 2105 772 60.1 77.3 9.6

--Group ? S 6 597 420 15.4 57.9 35.6 Spot--Group 1 S 9 1806 767 39.1 87.6 7.6

--Group 2 5 3 333 219 27.9 61.2 28.0 Pink and white shrimp S 1 48 44 8.3 11.4 81.2 Brown shrimp S 3 249 241 3.2 7.9 89.2 Penacid p stlarv;e S 2 131 119 9.2 15.1 77.1 Elue crab S 1 26 20 7.7 0.0 92.3 Blue crab megalops 5 2 203 135 3.0 11.1 86.3 Bay anchovy S 1 596 59 90.1 100.0 0.0 Hardback shrimp S 1 123 41 66.7 34.1 22.0 F = Fast screen operation; 5 = Slow scree 1 operai.lon '

aNumber of organisms that were found dead 4 collection gear i number collected.

b Humber of organisms that died af ter belt.g stocked in tanks s nur ber stocked.

cl00- ((a) (number collected) + (b) (number stoded) + (b) (other live organisms collected but not stocked)) e number collected.

M M M M M M M M M M M M M N ' M M M Table 19 Survival percentages for control organisms collected for survival studies at the BSEP dur'ng 1984 and 1985.

Number Percent of Number Number Initial latent Total Taxon Trials Collected Stocked Hortality a Mortality D Survival C

~

Croaker--Group 1 16 1392 1095 14.1 9.9 77.4

--Group 2 9 2550 611 0.9 1.8 97.4 5 pet--Group 1 10 1361 895 7.1 12.9 80.9

--Group 2 3 973 213 0.6 0.9 98.5 Pink and white shrimp 7 561 347 2.7 4.9 92.4 Brown shrimp 5 323 304 3.4 23.4 72.7 Penaeid postlarvae 2 115 112 2.6 8.0 89.6 Blue crab 5 238 100 0.0 6.0 94.1 Blue crab megalops 4 362 231 7.2 7.4 86.9 Weakfish 3 155 116 3.2 40.5 51.0 Searobin 4 104 97 1.9 1.0 96.8 Blackcheek tonguefish 3 444 116 0.2 2.6 97.6 Bay anchovy 2 60 48 20.0 56.3 29.3 Striped mullet--Group 1 1 23 23 0.0 4.3 95.7

--Group 2 1 35 35 0.0 0.0 100.0 Flounder 1 21 20 4.8 0.0 95.2 Hardback shrirap 1 51 50 2.0 8.0 90.3 d

Number of organisms that were tcund dead ir collection gear a number collected.

D Number of organis;ns that died af ter being stocked in tanks a number stocked.

c100. [(a) (number collected) + (b) (number stocked) + (b) (other live organisms collected but not stocked)) e number collected.

M M M M M M M M M M M M M M M M M M M Table 20 Comparison of. reduction of larvae cropped by the 95EP as a result of fine-mesh screens and flow minimiza-tion.

Percent of Larvae Percent Approximate Surviving after Het Average Reduction Not Entrained Impinged Impingement (49%)I Not Impinged Reduction Summer and Winter 1 Two fine-mesh screens 82a 82 40 N/A 40 (winter) 32 2 Two fine-mesh and One 9.4-mm screen 4B b 48 24 N/A 24 (summer) 3 Flow minimization 47 C N/A N/A 47 47 (winter) 37 d 27 27 4 Flow minimization 27 N/A N/A (summer) m 5 Both 1 & 3 90" 439 21 47C 68 I (above) k 6 Both 2 & 4 63 I 36 h 18 27 d 4S (above) dFrom Table 12 measured reduction due to fine-mesh screens.

b66% (hypothesized reduction with two fine-mesh Irather than threel and one 9.4-mm screen) m!nus 18% (hypothesized 100% reduction with only fine w sh minus 82% measured reduction from Table 12).

c,dPercent reduction in organisms entrained due to the corresponding reduction in flow based on pump information.

e(100% -a) x c + a f(100% - b) x d + b 9e-c h

f-d I from Table 16: percent survival of the eight taxa tested 35 urviving after impingement (21%) + c E5urviving after imping'ement (18%) + d

_ = .

-w--_.,_ - - - , - - _ . , - - - _ - - _ , - _ - - - _ - - _ _ _ - - - _ - _ _ _ _ _ _

N e .

- w > 5

- b- w p

/ ~

g f3 D J< [

s <c. w a

$g CB C 5 a

• <c< c w .:

.J W 2 e 2 C >- J, w - < E! O >-W c  :

H M Oe "

< 2g*9w  :

a. i: e : = c x 4 w -

h J N

,m u

3i. o s < e 4  :

i'

~ , ,

Ji m -

47 ii< . -

4 .:

g i! i w -

?< , -r, i i Ci4  ; , C.

- 5

.. 4 , 2.

• i'.

i < 7 -* 4 4

, 1 -2y.

i t 4

- s i r

. * - ~.

. I A ~,.

.t

• ! i e mv

- ,y8,. sc f nM 3 2

.:t

.h

/  :

~, j a  % J e b,,o'k =

u

@%n 1 e e O 3 H M. W

=m e.

(W C

f e- 7

-t u, J( ,.) =

d j c- 9 e

i e  :

'- C 7 L

nT n=

W J

W 6 *

=

}

4 f g C

/ d =

) x 0 n-  ;

= y 58MB W

o- a= g E

W

__ -_____._____-.-_-_.-_-----_-___--------_.__.__-_--__-_.__--._._.-_-__--__.____-_-__-.____--____-____a

0 I

I s I

- e = -=E .s 5,8 44 g E g e S b I -

I ' $

I i

2

( l

% e E

! l g .

.r

/ <

j I .

=

k i

I w-y =

II.

a g

c 3o 9  :

l / Y*

'N  !.!,

?

3 3

I s.

t

's

!,*6 .I I

s I \-

i x a I "

% 4; i I '

il I

I RIVE R 35 g\

g Y'5 ag g V \^

vs-u(9s.k \\\P t d

52 4

\ 'O I M) 'p IW J l m,'O be f 'h' / ',f U

S O N D J F M A M J J A S O N D E C O E A E A P A U U U E C D E P T V C N 8 R R Y N L G P T V C l; 1983 :l: 1984

l STATION *-+-* MG15 D-D D MG29 + +-+ M3 4 2 (DOWNRIVE RI (MIDRIVE R) (UPRIVER)

R I 40i 35 1j CREEK 304 s

i 25}4  !

N l "';"8, W ,. 8, ,\ ^\[l',.s.,

" 10-1 y i j i l h----c sa y ys....,A. , ,

\ .. '~.,  ;, ,

a,,

,,, . , , " y, - +

+

~

-+cj, , , , ,

S O N O J F M A M J J A S O N D E C D E A E A P A U U U 0 I

E C E P T V C N S R R Y N L G P T V C l- 19 h l- 1984  : 1, I STATION W Boldhood Creek

+--+-+ AlIlootor Creek O-D-D Wolden Creek I Figure 3 Bottom salinity values from selected river and creek stations in the Cape Fear Estuary, September 1983-December 1984.

I y e

I 4 40 35d 3 m-e l _.

0 25 E -

A l a 23:

! t s-t -

3 18~

E ~

s_

i O~, . ,,. ,,. ... ... ... .,. ,. ... ,,. ... . .,. ... ,. .,

S O N D J F M A M J J A S O N D E C D E A E A P A U U U E C 0 C I l" P T 1983 V C

- l :

H B R R Y N

-1984 L G P T V C Ll LEGEND: STATION *-+-* HG15 0-D-0 HG29 +--+ -+ MG 4 2 a

(DOWNRIVE RI (MIDRIVER) (UPRIVE R)

I

, I 40-CREEK 35-E e=%.

nu 25 N

,. yD \ '

s o '\,

.  : 4 , 0 n

N' I h s ie- -

/A',/

~

• z,[

O~i . .,, ..

S O N D J F M A M J J A S C N D E C D E A E A P A U U U E C D E P T V N

_I-l: 1983 C

l:

B R R Y N L G P T V C 1984 :l I STATION *-+-* Bo l dhood Creek

+--*--+ A l I l oo t or Cc.3h O-D-D Walden Cr .k I Figure 4. Bottom temperature values from selected river and creek stations in the Cape Fear Estuary, September 1983-December 1984, y ee

7 4- ~ , -

M M N M. M M M M M M M .M M M M WN O U M 9--

4 l

7_ .

! ' *'f ," -- --

~

' ' ~

~ ~ _

• _ _,; ._ _ _ . -, _ _ . _ . -

=+ 6- * ,,,.__ .__

, j g , . .. .

s- j -

i m

(f

( j' j

O

--=4- '

O J r Z

< 3-m N E 2-No Oste I

g ,. AvuHable 0-....,.......,..,...........,..,..,..,..,..,..,.,..,..,..,..,..,..,..,.i----i--ii---r i I i 1 1 I i 1 9 9 9 9 9 9 9 9 7 7 7 8 8 8 8 8 7 8 9 0 1 2 3 4 YEAR '

OBSERVED ------- PRE D I C I E D + -+ -+ YE AR LE VEL Figure 5 Results of time series analysis of total larval /postlarval organisms collected in Wakien Creek, 1977-1984, showing IIse seasonal occurrence of organisms. (Density = number /1000m3 )

,. ~

9 4

8 . . . -

i LI -

> s

~

• i ,. .

7 .

a t

l

.' l ,'

jj ,

?

+ b. . l

• y .

,' '. l l I h m

Z m

- J

< g O .

~

A '..

O

, ~~'h .

. < i s'

O 4 I * '

'~ ', ,

y . ,

' *' ~ ~ ~"l~ ~ + . ._ l , ' .

7

. v- ~ ~ '._,_

_,i 4 ,.I 1

m 3 .

2 .

i:B l

l .

'/  :

• 7- '

'. (

y '.

k l

l' g ._

T"T"T"TTT"T"T"T"1 "r"T"T"T"T"i ' ' s - ' s ' ' i ' ' : ' ' T"i' i ' s ' i ' ' : ' i ' ' i - ' s "T'T f"f ' ' s - ' i ' ' s - -T I I I i 1 I I I 9 9 9 9 9 9 9 9 7 7 7 8 8 8 8 8 7 8 9 0 1 7 3 4

'NO DATA AVAILABLE OllS L R Vtil phi lli t i tli + YtHR I t ytt Figure 6 Results of time-seriu analysis of larval /postlarval anchovy collected in Walilen Creek, 1977-1984, 3

demonstrating the regular perimis of occurrence with yearly variations. (Density = number /1000m )

m e am gun m e e e m M M W M M M' M M M M-100- '

w 755 c -

~

U ,.

u  : .-

ln 50i: j C -

~

1 E  :

N -

m T '

25- .

e 8 9 10 11 12 13 14 15 16 17 18 19 20 21 LENGTH (mm)

LEGEftD: DOWNRIVE m TIOuS w 82sh L9 RIVER LARVAL FISH LARVAL FISH - -- STATIONS M W M j Figure 7 Cumulative length-frequency anaysts of postlarv ' croaker collected from upriver and downriver larval fish stations on March 9,1983, indicating a larger F rcentage of smaller fish downriver.

M M

8 M d n

a 7

M 4 I

s n

i 1985 D i o

M k i E

T S

t t

a C t

. i I a D l s

M i E

R w

a r

t i

1 984 P l l

a

_. M i

_ m s

i n )t

. t oro

. f i

k f

_. e fe W i 1983 i n

no t

di en tc u

. s

-M *-

L E

l l

e r o p e

i DV ch H s c

~ EE mt a 982 A E s c m VL i

1 i

R n i Y ER a=

gE r

~ SA oU i

BE l P m -

i OY t

taC o I r4 i 1981 - o8 f

9 m )

f i

i i

l s1 sh y g au no ar s h e

i e t i9 r i 1980 e7 g i s9 e1 mro e *

- i i

f t f o de i

s n t i u b l

a 4 2

0 i 1 979 Rc se m o

gfc9z5: s m 8 e

r u

g i

F m

a m g

5-

? 4-w

, A

\

^

1 Y.

23-

)'

r O -

O -

z< 2-i -

r w

2 .

--.~.,_._. g ,, ,

l I~ k ~. -l t_. __._.._;g.

'~ . ; - - . .-.--;e d

q_ u -

) ._i b T.l e 1 kf(_j -

i i I '

I I I 4 I I I I I I I e i 1 5 I I I I I I i 1 1 I i 1 1 0 9 9 9 9 9 9 7 8 8 8 8 8 8 9 0 1 2 3 4 5 l YEAR OBSERVED - -- -- -- - P R E D I C TE D

• ---* -

• YE A R L E VE L Figure 9 Results of time-se rics analysis for brown shrimp collected in nekton small trawls at Stations I,4,7, aml 8 combined for 1979 through 1984. (CI'UE = catch per unit of effort)

l l

t 4 e

ed E

.2

• - C's C4 LS C 3 w m IlI "

b' h &

, "*[ ~

= l 4 -

/

- - c?> cc -

c.

p

-),.:

- (O

/ .r e5

_M - 3 b

i _ 'lllc $

s l ^

i .5 E l

r-

• - c'acc M 'c a 9 n.

i > -

EE a $$

k i ~

f J

b

,- - c', w cu $

a:

o$

wy Da = k,$

1. p.-

i I - > Irx v, =

j.D -

I

• cw Eg r'

'1 e__

o .- e

[ -.

t - o>

g

• .P., "

. . .:. . ._^. '\ - cn cc - I ~-

\ . .s a 3s=

i ,3 -

.n 2

\

~

n u '

\ E. R.

~

\

.E*"

- cn cc a ea

\ _

\ [ *b E

_ .d#'

~

5y

[-=>~"' 50 r m ca -

e h..

a:

(l+ BndD)'D01 NV3W e

L[e 72

t E

i E

E E a 5 E gt-y

=

g r (

• a G .i, h .i

<l a -

g, si y t E

l  !."y! } s g

1-gr j .

i  !!

=

!, I f c

rg gr . m -

I r- e a =

n8 5 l jg- .- E.1 -

.M I

4

_K

$?g=

c, ,

a e3 $

.E -

.3 E it E!

E i; vce.

I w.

.a

'I >

a s --

b zr o 4

I .ia a

n g ,

1 1

L I

W ..< wo ...

Q E

, e -

-%~ -

• 00 V cc P

4W emSur M M ,_

,.'  % - w d

_.

• sg I ._

e~

M y

b

' I *==

g

• tl0N g i ) , 6

i. // S

• ~ ~ ~~~~ ~ ~ ~ ~ "

,.asr.=;:=gl==g- p g g- g _~

s =- E I M k

I I E *WD 0

oc l ~

$ 5

.%

• B

% w

% *b@

3, gang E a  %

$' 3 oao e~

g nM gE i ---.~.___. w _ __

-.x_-

-g.

• • l'"e. sh

\

• h f*

) wk + $

.I ~ '"' ~ ~.'" " W.i_ Q _ _ _

J ' '

~

a E a g

% ~s' il i  %

oe c q .w

) '

.i G

- E

. , ~ ~. - -- - -

EA ~

~ k~.-[-% s ***

• 14J ~

.pg N t' 4 I v.

0 0 r- .. ...

0 T C

C C C C C C

h n, c a

e o e 9.. e C o

e. e e I O C

"* o e e O O C C C C C O Q c 2

O O M @ $ v rd e-

• / I' f" wnw- >.

I

$ 74

I I

I l s'

/

,' /

l

' E

' a l /./ 4 k

/

l / E O

I c

/

's s E c, .2

's .

.2

's  %

I s

's s >

a N D N

s N s ]

s I 4 l

I 3

T y

L o

A I i

.e s, x b

>E -

_I \ k

\ \ E C i

m

- o

\ w {=

I W 3

s

\

s s

s s

u .m

=g yQ h

t ~~

w s c c s *;; Eg 2 's y AE I E 's s '8 n E "b s o=

s E l \, .aC je ay s'

/ Ec

/ hb e' s <$

,s' 'N

,s s' m

~

R ;- i- ,

/ L w D

$ 3 k k b. k b, b b b b 'b 'b U '

W N

' b b 4 e e e e v 5 M d d

= (L+ A.LISN30)'D01 Nv3W I >

g e o--_-

M M M M M M M M M M M M M M M M M M M 1.5 - j 5

8

$ I

.t. T:  :-.,

3 S

4 .

• id *

5: n: . . 1. .

[ 1.0 _ ;. .

~

I

~

g . .,

1 .. \

f ,.

I  :. '.

l ,

y [ 0.5 -

m 0.0 -

T"T"T"T"T"i"a s - a - - a s ' i - i ' i ' a - - a - a "T"T"T"T- - - - i - s ' s ' s - - s ' 'T"T"T"T"T 1 1 1 1 I I I I i 1 9 9 9 9 9 1 i i 1 1 7 7 7 7 8 I I I I 1 6 7 8 9 8 1 2 1 1 5 YEAR Figure 14 Ratio of entrainment densities (ENT) to river larval fish (RLF) Station 25 densities of total fish, September 1976 through August 1984

m get a sur e m m _m seus em ses em m m mm W M M 100-M i  :

C 75 . -

I U M -

b 50 .

im

/

E -

~

/

p

~ d  : J /\

~ '

E 25- / "'

it I

/

02 ,. . ..

20 25 30 35 40 45 50 55 60 65 70 75 I LENGTH (mm) l Figure 15 Cumulative length distributions of bay anchovy impinged at the Drumwick Steam Electric Plant in 19fil arm! 1984.

M M 'M M M M M M M M M M M M M M M M 100-i ,

C 75-  :

U _

il -

P 50 . "" }mi

~

E R

C ~

~

E 25h l fi -

l T . l y

0- ,-

0 25 50 75 100 125 150 175 200 225 250 275 LENGTH (mm)

Figure 16 Cumulathre length distributions of menhaden impinged at the Brunswick Steam Bectric riant in 1981 amt 1984.

.=

I I

I I  : m

-N s~

I b

,-- C M

I .w o

E l h - ' o e,

E i

i I - ,

m

.e 2

s g g .

= m N

i

.E I

c.

' a

{

w ri

.li w o.

~

p c

f. 'b

[? 8, T

- o f a

{gj

~

- o gt q

(I m 4

3 ,,

.g

' e b-I n

h N U .3 b

I r

Q l j 1 ir , r cr ;,  ;

h C LA C Ln o ,k) a ~ v, N u.

,I t

I

'g ,,

- , m .

map sur ama sent ases immy amp aus sus sus me aus sur met m ass e uma mus 100-A

/

C 75- - I U i -

n -

50- ~

[R ~ ^

}

/

m C E 25-it -

T O ,. ... ... ...... .. . ..,.. . ... .. ..

20 40 60 80 100 120 140 160 180 200 LENGTH (mm)

Figure 18 Cumulative length distributiom er crosker impinged at the firumwick Steam Electric Plant in 1981 and 1984.

l'l 1jl)l1 a

5 4 8

- $ 9 1

l ,

g c

L l m

. . _ i n

r ow T - a u S

I r

l 1

i l r

- t I

l R

F iRI r s 1

]

1 l

s A'

d l

P t

n a

1 8 rf c -

l j

-' -y -< ,

1 [ s 5 f

E i

c r

ar

- t Y 9 1 r m

_ 1 f e i l

lE c

e F

l Or 1

- I 1 E

M M_ -

r-w a t m

a e

S

_ a k i

c s

i w s

M  :

n u

r l

5 I

_ e I h e

oi ji j ye f'g. 'g

( )' t g g R J y E )'g9 f'pWie n f'g. 'g

, t a

f (hI de g

n s

& i p

m i

m y

_ v

.. o M 5 h c

n

$ a s y E

a M - _

b h

f o

L

_ _ s i s i

, I d k t

e D1 7r ' i r I } p M , _ -

[4 -

1 y

4 8 l l 7 l l 1 l 6 t ( c8 9 7 e Td n9 1

T '

T1  %

e1 uo Mf l - - 5 U g mb

_ t M _7 f mi

< _ r- M a f v m

- - ~

I S . M 3 a

t t

g nm eo a

p M d Lc 9

1 h

e M 5 I i r

u g

F W

eiai9je y g , '3 'g  !# j W 1

1 g f'gG i p G j ge f'g,e f'p P t[f I M

M

,~

Q

+

fl{ill!l;l ll , l l lll l1,l

l I ~

RIVER 7  ; f i ST ATIONS l

ss

~

8:

l n4

\

i s 2-  ; (

h'; ,! -

d..._ , . . _ -

lN I k . h . . M . , $ . A .1, \L- ,

1 1 1 1 1 1 1

.I 9 7

9 8

9 8

9 1

9 8

2 9

9 0 t I 3 4 5 YEAR 5

OBSERVED PREDICTED

• 4-* YEAR LEVEL 3 e INTAKE I y

+

g. CANAL STATIONS

$ 4-I 8 3_

( /<

'g f e_ __ L o '

g-.____

j_ -

~

I

'j '

~

0, , , , , , , ,

]----[V1" * , ,

1 1 1

'I, 9 9 9 9 1 1 9

8 8 8 8 e 1 2 E 3 4 YEAR OBSEEVED FREDICTED I

• a-* YEAR LEVEL Figure 20 Results of time-series analysis forjuvenile/ adult spot collected by the nekton trawl at the river stations (1,4,7, and 8) 1979-1984 and the intake stations (5. 6, and 13),1981 1984 E ,,

I 3 RIVER 3j j ST ATlONS I

=. .

3 l l 2-l \

O.

a

1.

~

b  ; .- * ~ ,

u . >- -. .

I 0-l , , , ,,,,, ,,

I 1 1 1 1 1 1 1 9 9 9 9 9 9 9 7 8 9 0 S

1 S

e

{a E 4

E 5

YEAR OBSERVED PREDICTED

• YEAR LEVEL I

/ '

INTAKE CANAL

., 3 - STATIONS I I.

e I

ep I o' c3

,1-

s ,;

2 -

9~ . _;

0- 3 I I I I I I I I I I I

I t'N 1 1 1 1 1 1 1 I 9 8

1 9

2 I

9 8

3 9

8 4

9

?

5 YEAR OBSERVED PPEDICTED

• 6 YEAR LEVEL Figure 21 Results of time series pr-lysis of juvenile / adult croaker collected by the nekton trawlc' .ie river stations (1,4. 7, and 8) 19791984 i and the intake stations (5,6, and 13),1981 1984 83

I I  !

HIWH ,

f; ' f f

f CTAllONS lj k 3

8:

a .

4

'l .

1

= . _' . . . -

-- j ' ' * ~ -- ,,, .

8 g; L

_lb A.

, e- r r m I

1 1 1 i i i i , , .

1 1 1 1 1 4

9 9 9 9 8 8 8 1 2 4 YEAR i

OBSERUrp -

ppE01CICD

• ~* -

• Y E A R L E VE L INTAKE i  ;

CANAL 4- STATIONG

$' 3

$I .D J

g a-I a 5, \

t 51- ,s 7'

t ,_--- - - ,

g_ h /

-syg----)- h*

l 1 1 I 1 1 9 9 g 8 e I

I 4 5 YEAR I

OBSERVED PREDICTED

• • -* Y E A R L E Uf L Figure 22 Results of time series analysis for Jm enile/adu *. rnenhaden co!!ceted I by the nekton trawl at the river se.s ..s (1,2, s 7,8, arxl 10) and the intake stations (5. 6l and 13),1981 1964, 84

I l E En l .

CD eg N

t-v

==

I w 2

O E

, O M b m - 2

- b m O

I, 4 em A

'S w

' 5

- c 5

2

. o -

v c I 3 O

1,r

'm

.!'g 8,

l,'  ;

i E , ae

m O T3 em8.:

jy I .,

i

-H O

Z w

{n-

~

OmC

~ .1 h

1

' O Co h0 w .t

CT

'} *!x..I.

I . C

~

w )R, , -

DE ea I \,

s-FQv I c' E m-1 8' A .. .2 w

.k v-

, O $A t

C w .!g

'g .

I. -;

,, , ,, y" .

J

~

O A C w c DE O tw m N V **

I UDE 1WNUWCH N k

E I [E I

I ee

l  ! l l l 1

\!l e

g a .

s u

a .

r )

O e

m I e 1

=

r a

t 7 m ,

a s 0 4 5 s 2 s s n u E o D i a -

,. 5 2

I S

T S t

t a

(

- 2 U e su - O t k

s -

., 0 t

s u

o

- 0 -

i r 2 v u -

e r

. m, -

t

., 5 n

7 r o

r 1 k4 u

s e8 n9 e1

,. P ht g S yi n

s ) r u I m

bu d d a (

m E D ee t r 5 H I

S~

cctu 2

n I

. T I c ou 1

G i cr m -

N E

k r s e n t

0 L a o

~- 0 os r r i

m . 1 ce s / f v od i

, i sshe

. m -

5 7

l yt a) e ~ n3 a1

. yd cn s / . 0

. na u

s

. 5 e.

p6

<5 e

r f s s -

vno u :l:  :

i:

5 D i

t gt i

na a 2 3 : i i

et J . F G

l S e(

i v e E t l

m . 0 L aks a 0 m- - - ' ~

5 m _

l un mid 0 5 0 .

r 0 7 5 2 Ca un 1

u s

u 1 cut PERCEtiT 4 2

e r

s a

= u g

m P a

p u

s m g u

lllfIl l ;l(t lllI\(;ll I l l l