ML20079N234
| ML20079N234 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 12/31/1976 |
| From: | Marcy B, Morgan P, Owen B NUS CORP. |
| To: | |
| References | |
| RTR-NUREG-1437 AR, NUDOCS 9111110122 | |
| Download: ML20079N234 (37) | |
Text
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l'RAIRIE 1sLAND NUCLEAR CLN PLA ATTAcimrNT (,
'SECTICN 316(b) LLMONSTRATION FOR THE PRAIRIE ISTAND NUCLEAR GENERATING PLANT ON TIIE MISSISSIPPI RIVER NEAR RED WING, MINNESOTA PREPARED FOR NORTHERN STATES POWER COMPANY MINNEAPOLIS, MINNESOTA BY MICHAEL D.
DAHLBERG, Ph.D LUISE K. DAVIS JAMES W. ERICSON
.j VINCENT R. KRANZ BRIANT R. OBLAD B RADFORD B. OWEN, Ph. D.
NUS CORPORATION f
PZ,TTSBURGH, PENNSYLVANIA DECEMBER 1976 s
j-APPROVED BY_
y
/M./
[
BFADFORD B. OWLS, OR., Ph.
f
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PROJECT MANAGER
/
/
MRTON C. MARCY, JR., NM
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AQUATIC ECOSYSTEMS DEPAR '
T
['a PAUL V. Q GAN, VICE PRESIDENT M4D GENERAL MANAGER ECOLOGICAL SCIENCES DIVISION 9111110122 731D31 l
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t TABLE OF CONTENTS Page 1.
STATEMENT OF THE PROBLEM 1
2.
SUMMAFN.
3 3.
DESCRIPTION OF THE PLANT 10 3.1 LOCATION OF PLANT AND INTAKE.
10 3.2 INTAKE DESIGN 14 3.3 OPERATING MODES 17 3.4 INTAKE VELOCITIES 19 3.5 INTAKE FLOW VOLUMES 20 3.6 COOLING WATER TEMPERATURES.
22 3.7 BIOCIDES.
23 4.
DESCRT'*0N OF THE AQUATIC ENVIRONMENT NEAR PINGr 26 1
4.1 HYDROLOGY.
26 HR 4.2 WATER QUALITY.
33 4.2.1 General Characteristics.
33 1
4.2.2 Water Temperature.
36 35 f.2.3 Dissolved Oxygen.
i 4.2.4 Other Existing or Planned Stresses.
41 4.3 AQUATIC ECOLOGY.
42 4.3.1 Trophic Structure.
42 4.3.2 Primary Producers.
43 1
4.3.2.1 Phytoplankton.
43 4.3.2.2 Periphyton.
45 4.3.2.3 Aquatic Macrophytes.
46 4.3.3 Zooplankton.
47 4.3.4 Benthic Macroinvertebrates.
50 4.3.5 Fish and Fisheries.
76 4.3.5.1 Sport Fishery.
80 4.3.5.2 Commercial Fishery.
89 4.3.5.3 Tag and Recapture Studies.
91 4.3.5.4 Trawl Studies.
95 4.3.5.5 Seining Studies.
100 4.3.5.6 Electrofishing-Studies.
107 4.3.5.7 Trap Netting Studies.
119 4.3.5.8 Gill Net Studies.
131 4.3.5.9 Summary of Fish Studies 135 4.3.5.10 Spauning and Nursery Potential
'36 4.3.5.11 Spauning and Life History 1
Information.
138 l
l
j 4
l 1
l TABLE OF CO!! TENTS (CONTINUED)
Page
{
5 INTAKE-RELATED STUDIES.
139 i
5.1 INTRODUCTION
139 5.2 METHODS USED FOR INTAKE RELATED STUDIES.
140 5.2.1 Entrainment-related Studies.
i 14n t
5.2.1.1 Phytoplankton.
140 5.2.1.2 Zooplanktc'.
144 I
5.2.1.3 Fish.-.
148-5.2.2 Impingement-ralated Studies
.', 3 5 5.2.2.1 Data Collection.
155 5.2.2.2 Statistical Analysis.
157 5.3 RESULIS OF INTAKE-RELATED STUDIES.
160 5.3.1 Entrainment Studies.
160 4
5.3.1.1 Phytoplankton.
160 5.3.1.2 Zooplankton.
164 5.3.1.3 Fish.
160 r 5.3.1.3.1 Taxonomic Com-l position.
160 )
5.3.1.3.2 Comparison of Sampling Locations 171 5.3.1.3.3 Diel Variations in Fish Entrainment.
105 5.3.2 Impingement 106 6
IMPACT ASSESSMENT 23C 6.1 PRIMARY PRODUCERS.
238 6.2 ZOOPLANKTON.
240 6.3 BENTHIC MACROINVERTEBRATES 241 6.4 FISH EGGS AND LARVAE ENTRAINMENT.
243 -
6.5 FISH IMPINGEMENT 258 7
LITERATURE CITED.
264 APPENDIX 1 INTAKE VELOCITIES AT PINGP, JUNE 23 AND 28, 1976 APPENDIX 2 NOTES ON SPAWNING AND REPRODUCTION OF 26 SPECIES OF FISH OCCURRING NEAR PINGP APPENDIX 3 MEAN AND STANDARD DEVIATION OF DATA
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ON EGGS AND YOUNG FISH COLLECTED IN PINCP ENTRAINMENT STUDIES, 1975.
l
i I
.i TABLE OF CONTENTS (CONTINUED) i l
APPENDIX 4 RESULTS OF CORRELATION ANALYSIS OF FISH IMPINGEMENT, PLANT OPERATING AND WATER TEMPERATURE DATA AT PIMP, 1975.
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l
l l
4 2.
SUMMARY
3 Section 316(b) of the receral Water Pollution Control Act Amendments of 19' aquires cooling water users to dotarmine biological effects of their intake systems and to demonstrate that the design, construction, location and operation re-flect the best technology available for minimizing impact.
Under the National Pollutant Discharge Elimination System (NPDES) Section 402 of P.L.92-500, Minnesota has been given the authority to administer the law using the Section 316(b) amendments and Minnesota Regulation WPC(u) (3).
}
}
The Minnesota guide for the administration of Section 316(b) requires the demonstrator to show the environmental effects of cooling water intakes through documentation of the magnitude of impingement and entrainment impacts (MPCA 1975).
Supple-mental information on the aquatic ecosystem in the intake region is also requested.
Federal and state requirements have been addressed in this demonstration by providing extensive baseline data and a detailed presentation and analysis of entrainment and impingement data at the Prairie Island Nuclear Generating Plant (PINGP).
Northern States Power Company (NSP) has conducted six years of studies of the Mississippi River ecosystem near PINGP and, since plant operation began in 1974, N3P has conducted 1,
3 i
1 1-
P extensive intake studies.
The river at PINGP can be classified as somewhat eutrophic and supporting a healthy and very diverse flora and fauna.
The main channel and the associated side channels of slack water provide a mixturo of lentic and lotic habitats.
I The entrainment of primary producers (phytoplankton) reduced 4
standing crops of chlorophyll a but did not produce detect-i u
able effects en total numbers of algae.
Chlorophyll a reduction usually amounted to 50 percent or les-Prin.ary i
productivity of entrained algae was depressad up to 90 per-i cent from passage through PINGP.
Respiration was similarly depressed on most collection dates.
In summary, while a
the numbers of intact algae are not greatly affected by plant passage, the biological activity of the algal community 1 I '
l is frequently reduced by 50 percent or more.
?
b a
.y Studies of the effects of plant passage on phytoplankton l
~2::
failed to produce any detectable differences in the community E-6h of the main channel of the Mississippi River, either in yff species composition or primary productivity, corroborating y
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the conclusion of EPA (1976b) that entrainment effects or p,jh phytoplankton are usually of short duration and confined to a relatively small portion of the water body.
4
$1 S
4 9
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h ih Zooplankton entrained by PINGP was noticeably affected on e
H^
two-thirds of the dates sampled.
Usually only one or two in groups exhibited detectable mortality after plant passage.
m; h-Excepting cladocerans, some mortality was observed for all
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groups on some collection dates.
I i
zooplankton collected at the intake and discharge was also compared to :coplankton collected in the water body near the plant.
No significant differences in total cooplankton densities could be detectead, even within the recirculation canal.
Some preliminary data indicated reduction of copepods in areas directly within the discharge.
The low degree of entrainment i
impact at PINGP is further supported by EPA's (1976b) comment that in most cases the effects of zooplankton entrainment are of relatively short duration and confined to a relatively small area of the water body.
The entrainment of benthos was not studied; however, the extensive program of artificial substrate studios permitted s
a prediction of taxa most likely to be entrained.
Denthic entraimaent is not predicted to seriously affect aquatic communitie's near PINGP.
There are two potential sources of impact to the fish communities near PINGP:
entrainment of eggs and young 5
and impingement of larger fish.
A total of 8,371,000 eggs and 61,645,000 larvae and juvenile fish were estimated to have been entrained between May 12 and September 10, 1975.
However, larval and juvenile entrainment represented only an 4
estimated 6 percent of the 1,038,000,000 young fish estimated to have passed through the outlet of Sturgeon Lake during
~
the same period.
This represents a conservative estimate of loss to the total system because fish eggs and larvae are also present in the main channel.
p N
Entrainment losses of eggs and young fish were estimated to repr9sent 2,830,000 potential adult fish, 99 percent of a
which were forage species.
This loss of forage fish could I
decrease predator production by an estimated 3,400 kg (7,500 lbs) or 5,900 fish.
However, the larval and juvenile forage fish entrained represent only about 3 percent of the esti-maced number passing through the outlet of Sturgeon Lake.
l l
l Entrained sport and commercial species represented less than one percent of the total potential adult loss.
Sauger had the greatest potential loss among the sport fish (5,600 fish).
This potential loss is 0.9 to 2.4 percent of the estimated population for the Sturgeon Lake to Lake Pepin region.
The impact of the potential adult loss will-probably not be detectable due to the highly mobile nature of sauger in 6
l tha PINGP area.
Approximately 730 potential adult white bass are estimated to be lost due to entrainment.
This represents 0.4 to 0.5 percent of the population estimated i
between Sturgeon Lake and Lake Pepin.
Walleye, sunfish, crappies, northern pike and yellow perch were the other j
sport fish that were entrained.
Estimated adult lor O.
species represented less than 10 percent of thei.
i annual angler harvest, and probably a much smt.'
age of their actual populations in the PINGP t e,.
c.e i
?f Commercially important fishes that were entraa v ' * : c.' ',< -
9 freshwater drum, carp, buffalo, catfish, m ker anc i
s sucker.
The potential loss of carp and atfisa appe.r-
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i _
insignificant.ompared to commercial catch data, t' e
- # 7 ;-
on the other tr.a is unclear due to low commercial catches.
However, a comparison of numbers sntrained to estimated numbers of young passing through the mouth of Sturgeon Lake indicates low potential impact to resident populations.
4 Impingement analyses were conservative estimates based on the number of fish impinged per year in relation to the best I
population estimates that could be determined from available data.
7
Small fish, mostly 40-200 mm, accounted for most of the 146,063 fish impinged in 1974 and 93,466 fish impinged in
?
I 1975.
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?
Although gizzard shad composed more than three-fourths of the f
fish impinged, losses represent only 1 to 2 percent of the e
estimated 1973 Sturgeon Lake population.
I r
Potential impact on the channel catfish population was inconclusive due to apparently low population estimates I
based on trawl samples.
However, the numbers of young i
j impinged represent a small fraction of the number which could be produced in one year by the estimated adult popula-tion or number of catfish commercially harvosted in one i
year.
The numbers of impinged freshwater drum represented lu to 12 percent of'the young estimated for the plant area or North Lake, based on trawl collections, and 5.2 percent of the commercial harvest of adults in 1974.
Annual impingement losses of young white bass, sauger and walleye were 0.1 to 1 percent of the estimated sport tish populations between Sturgeon Lake and Lake Pepin.
Potential i
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i adult losses would be substantially less due to mortality between the young and sport harvest sizes.
i The combined impact of the impingement and entrainment
~
losses for fish, plankton and benthos is considered to represent an acceptable IbVhl of impact for a generating facility of the size of PINGP.
Losses to lower trophic L als are, at most, barely detectable in the immediate
~
plant vicinity.
Fish entrainment losses represent such low percentages of ambient populations that no short or long term effects are expected to be detectable.
The numbers of young fish impinged per year appear to re-present only a small percentage increase in the mortality resulting from natural causes and fishing.
The numbers of young white bass, walleye and sauger impinged are approxi-mately 0.2 percent of their adult populations L,
the region
~
and represent an even smaller percentage loss of recruitment into the sport fishery.
Due to the apparent excess of forage fish (most gizzard shad) and minimal cropping of sport fish, there is not expected to be a noticeable change in the dynamic predator / prey relationship or in recruitment into the harvested populations, t
9 i
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'6 IMPACT ASSESSMENT l
6.1 PRIMARY PRODUCERS Phytoplankton is likely the most important primary producer in the PINGP area of the Mississippi River.
Assuming a j
relatively random distribution of phy+.oplankters, it may be assumed that entrainment will be directly proportional to water appropriation.
Th the entrainment of phytoplankton is estimated at 0.1 t.
t over the year based on 1975 operation data (Tab,
'lowever, in a normal
<< :nment would follow a year the seasonal distric different pattern (see Sectiu l
l.
The damage to phytoplankton resulting from entrainment has been studied for two years, ma).nly in the summer and fall (see 5. 2.1).
Standing crops of chlorophyll a and the rates of photosynthesis have been shown to be reduced after passage through PINGP.
Under two unit operation the reduction of
~~
productivity of entrained phytoplankton may exceed 50 percent.
In spite of the obvious degradation of photosynthetic ability of the entrained algae, Baker (1975) was unable to detect any effect on the productivity of main channel phytoplankton i
below the plant, based on 1974 one unit data.
No conclusion was drawn from 1975 data; however, the lack of detectable difference due to Sturgeon Lake input to main channel 238
l-productivity (Baker 1975) would indicate that a reduction of the normally higher Sturgeon Lake productivity through entrainment would only further serve to mask effects of the lake or plant.
The conclusions of Baker and Baker (1975, 1976) indicate that there are no detectable differences in composition or density of phytoplankton in the main river that may be attributable to PINGP operation.
Considering the scmewhat enriched status of the Mississippi River and the potential enhancement of already high algal populations due to Sturgeon Lake inputs, reductions in algal production due to entrainment at PINGP cannot be considered an adverse effect.
The conclusions of the phytoplankton
{ studies at PINGP agree with EPA (1976h) which states that entrainment effects on phytoplankton are of short duration and usually confined to a relatively small portion of the k
) water body.
k e
i 239
m
.+.h....
4 53 6.2 ZOOPLANKTON Zooplankton is susceptible to entrainment in proportion to the water appropriation at PINGP, assuming a relatively uni-form distribution of organisms in the source water body (which is chiefly Sturgeon Lake).
Entrainment studies (see Section 5.3.1.2) have shown some detectable mortality among three of the four major groups of zooplankters.
However, in 1974, during one-unit operation, Szluha (1975) was unable to detect significant differences among stations associated with the plant and those outside of plant influence.
Daggett (1976) concluded preliminarily, tnat while total zooplankton, totti rotifers and total cladocerans were not significantly different among plant-affected and control stations, there v
{
were reductions in copepod densities that could be associated htr with plant passage.
hy Entrainment effects appear to produce minimally detectable y
effects on the cladocerans in the discharge area of PINGP, a
~
but even the total effects of plant operation do not detect-Oj ably affect total numbers of zooplankton.
As noted by EPA (1976b), zooplankton entrainment does not present a potential Ey for significant adverse impact due to the tapid reproduction i
4[
rates and short life spans, j
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240 J
i i
6.3 BENTHIC MACROINVERTEBRATES 1
3
]
Benthic macroinvertebrates comprise a major link in the food
)
webs of the PINGP area (see Section 4.3.1).
A number of benthic organisms are sessile, some burrow, some attach to substrates and others move around freely on the river bottom.
Many benthic organisms drift freely or are scoured loose from substrates and me~* aquatic insects also enter the
)
l water column when emerging as adult flying insects.
Either of the latter cases make the organisms vulnerable to entrainment.
Species composition of these benthic organisms which may be entrained can partially de determined from artificial substrate data.
The organisms that colonize these substrates are generally non-burrowing surface-residing invertebrates that are likely to be the major colaponents of the normal drift fauna of the river.
Caddisflies (Trichoptera), mayflies b
(Ephemeroptera) and flies (Diptera) were the major groups D
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colonizing artificial substrates (see Section 4.3.4). Caddisflies 2
Were Hydropsyche, Cheumatopsyche,, Potamyia, Polycentropus, 7
Neureclipsis, Ceraclea, Agralea, Hydroptila and unidentified
] I
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species.
Mayflies included Caenis, Baetis, Isonychia, 1 l J k Heptagenia, Stenonema, Tricorythodes and Potamanthus.
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Plies were mainly represented by Chironomidae and lesser J
numbers of Chaoborus, Polpomyia and Simulium.
In some periods of 1975 the worms Naididae dominated collections.
241 e _
.e.
t i
Another estimate of the benthic invertebrates that may be 1
j entrained may be made from the emergence studies (NSP 1975) in which Hydropsychidae, Psychomyiidae and Hydroptilidae were the dominant families collected.
Representatives of these families would be entrainable during emergence.
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242 1
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6.4 FISH EGGS AND LARVAE ENTRAINMENT Analysis of the impact of entrainment of fish eggs and young at PINGP is based on the simple population modeling approach, described by Horst (1975) in which the number of larvae entrained is converted to an estimate of the number of adult fish that would have been produced had the larvae not been entrained.
1 If the entrained stage is an egg, the estimate of the number of adults lost is calculated as follows:
N
= SN
=2N, a
e e
g F
M F
where N
= number of adults in mature age classes a
f S
= survival from egg to adult stage N,= number of eggs entrained 2
F
= total life time fecundity of a female 2
= number of adults needed to be produced by a breeding pair to maintain a stable population If the entrained stage is a larva:
N, = S Nyy=SF 2
XN y e
where N, 2 and F are defined as above a
Sy = survival from larva to adult stago t.
[
243
~
k N1 = number of larvae entrained 4
S
= survival from egg to larva e
The following assumptions are made in this analysis :
There is 100 percent mortality of entrained eggs and 4 -
o J.j-larvae on passage through the planc i
s; o
The populations are at equilibrium and the total lifetime fecundity produces 2 adults That 0.5 percent of the eggs produced by a species o
with high fecundity and/or randomly broadcast eggs and little parental protection survivo to the larval stage y
g}
that 75 percent of the eggs produced by a species which o
q 24 exhibits nesting behavior and a high degree of parental care survive to the larval stage.
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lh
- Before estimating the number of adults lost it was necessary u
g to consolidate some taxonomic groups because of a lack of a
y reproductive information for certain taxa.
In some cases, i -
such as the suckers, the individuals which could only be 3
icentified to family level were divided among the genera E
of that f amily based on the proportion of the larval catch 1f comprising each genus.
If only a few larvae were captured k
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in each of several taxonomic categories, they were combined 9
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at the family level with the exception of emerald shiner and carp.
Larvae were nev grouped above the family level.
5 k
l 244
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' * * " ' ~ " ' " ' ' ' " ' " ' ~^
1 A total of 8,371,000
(+ 4,694,000 at 95 percent confidence interval) fish eggs and 61,645,000 (t 34,529,000) larval and 1
juvenile fish were estimated to be entrained by PI!;GP between May J _ m1 4eptember 10, 1975_.
The number of larval and juvenile fish entrained represents about 6 percent of the total number of larvae and juveniles passing through the Sturgeon Lake outlet during the same period (based on a conservative estimate from data collected by the MNDR of I
about one billion larvae and juveniles, Section 5.3.1.3.2).
Weekly estimates of entrained larvae and juveniles ranged from less than 1 to 85 percent of the estimated Sturgeon Lake production.
These estimates are conservative because y
they do not take into account the larvae and juveniles in 24 the main channel.
No estimates of larvae and juveniles in the main channel are available.
j The entrained eggs and young represent a potential loss of about 2,830,000 adult fish from at least 28 taxa.
The number of eggs and young entrained, the number of adults lost and the values for fecundity and survival used to calculate the losses are summarized in Table 6.4-1.
I I 1
F Over 99 percent of the potential adult fish loss consisted
{
of 8 taxa of forage fish.
Taxa of either sport or commercial 3
!s importance (e.g., sauger, walleye, white bass, sunfish, I
T 245
c, uG b
G p
TABLE 6.4-1 CALCULATION OP IDSS OF ADULT FISH DUE PJ ENTRAINMENT OF EGGS, IARVAE AND JUVENILES AT PINGP IN 1975.
(Sheet 1 of 2)
Number Survival Larvae Produced Survival Number of Economic
= _ thtrained Fecundity" Egg to Lsrva by One remale Larvae to Adult _ Adults Lost Classificat*2 C Dorosoma cepedianum 10,370,000 1,560,000 0.005 7,800 0.0003 3,111 r
Coregonus clupeaT6fals 4,000 178,000 0.005 900 0.002 8
C III&lon terglaus 1,221,000 60,900 0.005 300 0.007 8,547 C,s Esox Tucius
~
4,000 981,000 0.005 4,900 0.0004 2
s C prinus carpio 3,257,000 7,360,000 0.005 36,800 0.00006 195 C
y Ti b
Notro L atherinoides 15,961,000 2,900 0.005 15 0.13 2,075,000 r
Cyorinidae 1,575,000 2,900 0.005 15 0.13 204,700 r
b Larproces upp 4,598,000 619,200 0.005 3,100 0.0006 2,759 C
Catostomus co.amersont 13,000 954,000 0.005 4,800 0.0004 5
JO C
i Ictirbus spp 6,617,000 1,610,000 0.005 8,000 0.0002 1,323 C
Moxostoma spo 36,000 135,000 0.005 680 0.003 108 C
y Ictalurus pun'etatus 325,000 214,800 0.75 160,000 0.00001 3
C o,
Noturus gyrinus 3,000 200 0.75 150 0.01 30 r
fylodictis olivarls 16,000 108,300 0.75 500 0.004 64 C
Percopsis omisconnycus 25,000 1,400 0.005 7
0.3 7,500 r
Horone chrysops 7,297,000 3,390,000 0.005 17,000 0.0001 730 s
Amblop11tes rupestris
. 5,000 6 3,0 C9 0.75 300 0.007 35 s
Lepomis gIEbosus 122,900 16,425 0.75 12,000 0.0002 24 s
C macrochirus 742,000 97,000 0.75 73,000 0.00003 22 s
Eomoxis spp 480,000 462,200 0.75 35,000 0.00006 29 s
EIheostorna nigrum 67,000 1,600 0.75 1,200 0.002 134 F
Perca flavescens 102,000 436, BOO 0.03 13,100 0.0001 10 s
Percina caprodes 88,000 6,000 0.005 30 0.07 G,160 r
P. shumardi 1,711,000
-1,200 0.005 6
0.3 513,300 r
2 5IizostedTon canadense S. vitreum-1,881,000 159.500 0.005 800 0.003 5,643 s
319,000 2,257,000 0.005 11,300 0.0002 64 s
FercIdae 956,000 477,000 0.005 2,400 0.000s 765 Aplodinotua grunniens Eggs 7,484,000 1,300,000 0.005 6,500 0.0003 11 Larvae & Juveniles 3,408,000 1,022 Unidentifiable Larvae 403,000
TABLE 6.4-1 (Sheet 2 of 2)
Survival Larvae Produced Survival Number of Economic C
Number to Adult Adult Lost Classification Entrained Fecundity
- Egg to Larva
__by One Female _ Larvae Unidentifiable eggs 887,000 Unidentified Larvae 39,000 t
Total 2,831,304 Total 2ggs 8,371,000 2,809,933 i
rorage Total Larvae & Juveniles 61,645,000 Sport / Commercial 21,339
~
I (1973): Wrenn (1958) s Swee and McCrimmon (1966): Bodola (1955): Dalber fecundity information obtained from Scott and Crossman a
(1953): Winn (1958): Wolfert (1969): U1 rey, Risk and Scott (1968) l M
bAverage of fecundities of several similar species.
4
'F = Forages C = Commercials 8 = Sport.
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_ - _ _ _ - _ = -
2, crappies, freshwater drum, carp, buffaloes and carpsuckers) 2 represented less than 1 percent of the adults lost.
e Minnows (mainly emerald shiner) accounted for 80 percent of the potential adult loss.
Darters (logperch, river darter and johnny darter) and unidentified percids comprised the 2
1 next greatest proportion (18 pt. cent) of the potential adult loss.
Gizzard shad (0.1 percent) and trout-perch (0.3 percent) were the remaining forage taxa.
Since there are no catch statistics for forage species,
$2 another means of relating the extent of impact was used.
If gr it is assumed that each fish weighed about 8 grams (0.3 on, o
g-the average weight of young emerald shiner in the fall as
?
}f reported by Scott and Crossman 1973) when consumed by predators, o
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approximately 22,500 kg (49,600 lbs) or 144 kg/ha (131 3
lbs/ acre) of forage would be lost to the PINGP area (1600 ha MNDR study area).
If all 22,500 kg were consumed and were 4*
converted to predator biomasc at an efficiency of 15 percent, T
about 3,4001.g (7,500 lbs) of predator production could be eliminated from the PINGP area.
The average individual g
l weight of the three major predators (sauger, walleye and T
f:
white bass) found in the area as determined from creel 1[
censuses between 1968 and 1975 was 0.57 kg (1.26 lbs)
Y
$g 248
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(Gustafson and Diedrich 1976).
Bared on this weight, the estimated loss in predator production would be 5,900 fish.
^
However, the surplus production of forage fish may be sefficient to accomodate both predation and exploitation due to entrainment with no loss of sport fish production.
6 If.these estimated losses are looked at by themselves, it appears that there has been a significant loss to the forage base in the PINGP area.
Another approach is to compare the number of young forage fish entrained to the total number
$b&
available.
This can be accomplished by using the larval
?
?
fish data collected in 1975 by the MNDR (Gustafson et al.
~
1976) at stations near the mouth of Sturgeon Lake to develop an estimate of the total number of young forage fish passing through the Sturgeon Lake outlet (see Section 5.3.1.3.2 a
for discussion of MNDR data). It is assumed that the taxonomic i
composition of the young in the outlet is similar to that at the bar rack in the intake canal.
The number of young forage fish entrained represents only 3 percent of the
[
available production (51 million young, based on Sturgeon 1
[
Lake outlet densities) of the North Lake-Sturgeon Lake I
complex.
Although sport and commercial species represented less than 1 percent of the total adult loss, the actual numbers of
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k 249
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-~
n 3
A I k j
q adults lost of several of the individual taxa appear to be high.
Approximately 5,600 saugers (based on all mature
'i age classes), one of the most sought after sport fish in I
the PINGP vicinity, were estAmated to be lost due to the l
entrainment of larvae (Table 6.4-1).
This represents about 0.9 to 2.4 percent of the estimated population between Sturgeon Lake and Lake Pepin or one-third the average spring angler harvest from section 4 of the PINGP survey
~
area, which annually contributes about 70 percent of the entire sauger harvest for the survey area (Naplin and gp Gustafson 1975, Gustafson and Diedrich 1976).
It is nearly w
2 18 times the annual harvest for the area above Lock and Dam iY 4
No. 3.
5
.v j
The impact of the loss of 5,600 sauger to the PINGP area iy fishery depends on the size of the population, the geograph-E j
ical distribution of the population and spawning activity
$4 and the proportion of available young entrained.
The T
'A greatest impact would occur if Pool 3 had a small, discrete 7
population of sauger and a majority of the spawning activity 2
for the population occurred in the lakes upstream of the PINGP 4
T 3
intake with.a large proportion of the young produced being if.
entrained.
If, on the other hand, the population was rather 4a Y
k e$
1m 250
g:
C
. Ss JP T h mobile, capable of free movement inte and out of Pool 3 j(
and/or spawning activity were spread over a large portion of b:1 the Upper Mississippi River, the impact on the population would not be as great.
Hawkinson (1974) stated that data from tagging studies con-ducted by Krosch (1969) and Finke (1964) indicated that the larger fish which inhabit the PINGP area are extremely mobile and move throughout the area between Taylors Falls on the St. Croix River and Lansing, Iowa on the Mississippi River.
Preliminary analysis of tag returns from the PINGP I
tagging study seem to indicate that the sauger found in the plant area are highly mobile (Gustafson et al. 1976).
On the basis of preliminary tagging data, it would seem that j
Pool 3 does not have a discrete population of sauger.
It
{
also seems unlikely that North and Sturgeon Lakes are uniqua and, as a consequence, are not primary spawning areas for the population.
There appears to be a considerable amount of i-similar spawning habitat in Pool 3 which would be available 4
to the sauger population utilizing the PINGP area.
E Further-
?
i more, the number of larvae entrained represents less than 3
{
percent of the sauger larvae carried out of Sturgeon Lake
! t jj during May, (assuming that larval drif t from Sturgeon Lake has a taxonomic composition similar to that at the Bar Rack l g Station in the intake canal).
s 251 e
I l
1 j
Because of the high mobility of adult sauger, the wide availability of suitable spawning habitat, and the low i
i proportion of sauger larvae available that are actually entrained, it is not anticipated that entrainment of larvae by.the PINGP will have a significant impact on the local sauger population.
/
Approximately 730 adult white bass were estimated to be lost due to the entrainment of larvae at PINGP (Table 6.4-1).
This represents only 0.4 to 0.5 percent of the population f
estimated between Sturgeon Lake and Lake Pepin and only 7 percent of the average annual sport harvest of 3
10,400 fish, and appears to be only a small portion of the I
total production for the North Lake-Sturgeon Lake complex.
(
If it is again assumed that the taxonomic composition of the I
larvae in the Sturgeon Lake Outlet is similar to that at the r
Bar Rack Station, about 2_50 million white bass larvae would be present in the North Lake-Sturgeon Lake complex.
Using the same method of calculation as was used for deriving h
entrainment losses, this would result in the production of 9
4 about 25,000 adults, nearly 35 times the entreinment loss.
?y.
j Nearly 11 million freshwater drum eggs and larvae were 3.
4 entrained at PINGP during the 1975 sampling period, resulting 4
Y
?
252 e*
h
f 1
in a potential loss of about 1,000 adults (Table 6.4-1).
This was approximately 1.5 percent of the population of young drum in the plant area, one-third of the total annual sport harvest (Section 4.3.5.1) and about equal to the average commercial harvest (pool 3) reported by the MDNR (Section 4. 3. 5. 2).
At present, however, this species does not appear to be heavily exploited by either the recrea-tional or sport fishery above Lock and Dam No.
3.
Sport fishing pressures in Pool 4 during the 1960's were 300 to 4
700 times higher than current levels in the area above Lock and Dam No. 3 and harvests were 38 to 50 times greater (Skrypek 1964, Sternberg 1969, Hawkinson 1974, Naplin and Gustafson 1975, Gustafson and Diedrich 1976).
During the same period, the abundance of drum in Pool 4, indicated by experimental gill net and trap net catches, was equal to or 4
?:
less than current levels in the area upstream of Lock and 7
Dam No. 3 (Skrypeck 1966, Anonymous 1964, Hawkinson 1974, Naplin and Geis 1975, Gustafson et al. 1976).
This indicates i
that the drum population in the PINGP area can stand consider-9 ably more exploitation pressure without serious damage.
f c
Other sport fishes sustaining entrainment losses include walleye, and species of suntish, crappies, northern pike and 3
yellow perch (Table 6.4-1).
The total adult loss was estimated to be 184 fish, which is less than 10 percent D
1 253
?
l ei in a potential loss of about 1,000 adults (Table 6.4-1).
1 This was approximately 1.5 percent of the population /of "i '
i
/
i young drum in the plant area (Table 6.5-1), one-third of the 1
\\
~
total annual sport harvest (Section 4.3.5.1) an about equal
\\
to the average commercial harvest (Pool 3) reported by the MNDR
\\
however, th s/
(Scetion 4.3 5.2).
At present, species does not appear to'be heavily exploited by either the recreational J
\\
b
)E or sport fishery above Lock and Dam No. 3.
Sport fishing
.t SE.
S pressures in Pool during the 1960's were 300 to 700 times higher than current levels in the area above Lock and Dam 8
\\
L No. 3 and harvests weres 8 to 50 times greater (Skrypok 1964, Sternberg 1969, Hawkinson 1974, Naplin and Gustafson
?
1975, Gustafson and Diedrich 1976).
During the same period, the abundance of drum in Pool 4, indicated by experimental gill net and trap net catches, was equal to or less than T
\\
current levels in the area upstream of Lock and Dam No. 3 (Skrypeck 1966, Anonymous 1964, Hawkinson 1974, Naplin and Geis 1975, Gustafsoa et al. 1976).
,This indicates that the drum population in the PINGP area can stand considerably e
j more exploitation pressure without ser4ous damage.
E e
Cther sport. fishes sustaining entrainment ' losses include
?)
walleye, and species of sunfish, crappies, n'orthern pike and
?
1 yellow perch (Table 6.4-1).
The total adult loss was Y
f.
i estimated to be 184 fish, which is less than 10 percent le 254
_w
1
~
1
?
of the combined annual angler harvest for these species.
(
The operation of PINGP should not cause a significant de-1 4
crease in the number of these sport fish available in the area of the plant,
,f i
commercial fish whose larvae were entrained at PINGP in-5
.[
cluded carp, buffalo, catfish, suckers and carpsuckers (quillbacks).
Since the MDNR publishes only total weights of harvested species it was necessary to convert the number of adults lost to weights for comparison to commercial landings.
This was accomplished by multiplying the number lost by an average weight per indiv! dual, which was usually obtained from information given in Scott and Crossman (1973).
All commercial fishery data were obtained from MDNR unpublished reports.
Nearly 3.3 million carp larvae were entrained in 1975, resultino in a potential loss.of 195 adults.
At an average weight of 9 kg, this loss represents 1,755 kg (3,869 lbs) or about 8 percent of the average annual commercial catch from Pools 3 and 4.
Over 6.6'million buffalo larvan were entrained, resulting in a potential adult fish loss of 1,323 fish.
At an average individual weight of 2.3 kg (5.1 lbs), the loss represents 255 h
l
g, kr;f.
f 3,04.) kg (6,708 lbs. ), an amount about equal to the avarage commercial harvest for Pools 3 and 4 during tha perted 1970
)
to 1974 (Section 4.3.5.2).
1 I
l i
Approy,inately 4.6 million carpsucker larvae were entica'.ned 3
~
in 1975.
This represents a potential adult loss of 2,759 fish or about 25,000 kg (55,000 lbs).
The average annual I.
catch for Pools 3 and 4 between 1970 and 1975 was 103 kg n
1 (227 lbs).
t.
%~
f' over 300,000 channel and flathead catfish young were entrained, resulting in an estimated loss of 122 kg (2b9 lbs or 67 fish) or 5 percent of the average ennual commercial catch.
LA.
[:
The mooneye i.' li ;ed as an incidental cat.ch in both the l
commer
- t. and sport fisheries statistics.
It has not been abundan
.n the catch of any type of experimental gear 4
fished in the PINGP area between 1973 and 1975, but in 1975
=
1 it accounted for 2 perce.it of tl.>.
larvae ent. rained at the PINGP.
The estimated number of adults lost due to entrain-
^
ment of larvae was 8,547.
This is considerably higher than C
the co*. ned annual sport and commercial harvest.
T 1
r r
Losses of; carp and catfish do not appear to be significant i
when compared to commercial catches.
The impact on the z
e 1
25G x
I" fishery of losses of the magnitude exhibited by buf f aloos,
carpsuckers and mooneye is unclear.
It is unknown whether 1
the low nurchars of these taxa in commercial landings are due to low abundance in Pools 3 and 4 or a lack of interest by commercial fishermen.
Experimental gear catch data suggests that these fish have been low in abundance in the PINGP area between 1973 and
('
1975.
However, if the number of larvae of each taxon at the outlet of Sturgeon Lake in considered, (assuming a y[
taxonomic composition similar to that at the Bar Rack Station),
t
[]
it appears diat the experimental catch may not he an adequate
[
indicator of abundance of these species.
(This is especially true since the MNDR data on larvae of Sturgeon Lake Outlet are probably relatively low estimates as discussed in Section 5.3.1.3.2).
Approximately 111 million buffalo larvae, 21 million mooneye larvae and 78 million carpsucker larvae were es.timated to have passed the PINGP intake in 1975.
These larvae would have been the progeny of 96,000, L
200,000 and 202,000 spawning pairs of buffalo, mooneye and carpsuckers, respectively.
Potential losses of adults due r'
to entrainment represent only a small proportion of those adults which produced young that were estimated to have passed the PINGP intake; therefore, it is not likely that significant impact has or will result from larval entrainment.
257 L
-____m_.___._____m_____-..-.___...m_-___
l h[ r
~
11r.
/ ?
r
@t 6.5 FISH IMPINGEMENT U
- fj Fish losses due to impingement at PINGP were 146,063 in 1974 y
and 93,466
'.n 1975.
The significance of losser of fish h.,'
because of impingement at PINGP can be s,ubjected to a general h
f.
evaluation based on comparisons with population estimates (Table 6.5-1).
g The most obvious result of studies at PINGP (Section 5.3.2) is the large numbers of gizzard shad impinged.
Most of the
(
gizzard shad were isnpinged during the. late f all and winter.
x As pointed out by Andersen (1975), the high impingement rates appear to be temperature-related.
A number of investi-getors have reported apparent temperature-related fall dio-offs of gizzard shad (Wicklif f 1953, Agersberg 1930, Miller 1960, Bodola 1966).
The large number of gizzard shed in Sturgeon Lake and nearby arcas and their sensitivity to temperature changes in the fall are apparently major factors causing high impingement rates at PINGP.
Andersen (1975) pointed out that gizzard shad die-offs in the PINGP area appear to begin when the water temperature falls to near
?',.
12*C (53.6'F).
r-
.?
{
Total numbers of gizzard shad impinged at PINGP were 136,667 in 1974 and 70,506 in 1975 (Table 6.5-1).
Bottom trawling Z'
data probably provide a low estimate of gizzard shad 4
I T4 258
__m 4
i
[
TABLE 6.5 -1 4
L NUMBERS OF *tAJOR r"ISII SPECIES IMPIfK;ED AT PINGP, ESTIMATES OF STANDING l
CROP BASED ON TRAWL SURVEY, SPORT CATCHES, Ar,T, ESTIMATES OF SPORT FISH POPULATIONS b
c d
l Total Impinged Trawl surve L Tag and recapture 1
l Plant area North Lake Pecerson Schnabel l
1914 1975 33.4 ha 439 ha g
Gizzard shad 136,.667 70,506 2,252 270,684 j
Channel catfist.
637 6,223 2,669 4,E18 22,720 i
White base 1,367 2,712 2,190 60,006 173,910 155,335 Crapples 1,704 2,030 417 154,176 Drum 3,143 3,789 66,220 58,692
(
Walleye 5
250 2,190 162,721 123,512 f
Sauger 13 417 1,752 609, BrY+
228,784 Sauger/ walleye 87 197 667 3,942 774,530 352,236 f
{
l N
1 in 1
"Six million estimated for Sturgeon Lake (Andersen 1975) bSection 5.2 Section 4.5, 1974 - 1975.
Section 4.5, Sturgeon Lake to Lake Pepin: 1974 and 1975.
i i
4
.I i
i i
i t
f
populations because this species is a filter-feeder and occurs throughout the water column (Scott and Crossman 1973).
Population estimates for the plant area are not directly comparable to impingement data because trawling was not conducted during the late fall and winter when most gizzard shad were impinged.
The MNDR estimated that roughly six million gizzard shad were present in the 324 ha (800 ac)
Sturgeon Lake in late summer of 1973 (Andersen 1975).
Assuming this to be a representative figure, the 1974 and 1975 losses represent approximately 1 to 2 percent of the i
i Sturgeon Lake population.
Losses of this magnitude would 1
not reduce the forage value of thin species.
O Trawl survey data are relatively appropriate for interpre-2
}
tation of losses of sport and commercial species because similar size fish occur in both trawl and impingement catches.
However, trawling yields low population estimates due to concentration by certain species in untrawlable habitats such as nearshore shallows, macroflore beds, or other cover.
4 I
The average number of catfish impinged (3,430) is roughly equivalent to the apparently low population estimates for the 83.4 ha plant area and 438 ha North Lake (Tuble 6.5-1).
However, the Peterson population estimate (22,720) and 1974 commercial landings (37,820 lbs) of adult fish suggest that 4
[
260 i
a _.
~
4 the number of impinged catfish reprenant a small fraction of the young occurring in the region.
Young white bass losses were comparable to the trawl popula-tion estimates occurring in the plant area and represent 6.8 percent of the numbers estimated for North Lake.
The young white bass represent about 1 percent of the sport fish populations estimated in tag and recapture studies.
Due to natural mortality, the number of whito bass impinged would e
'{
have yielded an even smaller number of adults.
A A
c The number of impinged crappies is greater than the popula-tion estimated for the plant area from trawl survey data, but represents only 2. 4 percent of the North Lake population.
Lcw population estimates in the plant area are probably dus to concentration of crappies in relatively unsampled habitate.
Freshwater drum in the PINGP area. wou,ld be highly vulnerable to impingement, judging by the large population occurring in the plant area.
However, impingement losses represent only 10 percent and 12 percent of the estimated young occurring in the plant area and North Lake, respectively.
Walleyes and saugers were impinged at a low rate relative to 4
other species and represent 43 percent of the estimated 1
261 5
i k-
II t (
1.
?!
plant area populations, 3.6 percent of the estimated North Lake populations and less than 0.1 percent of the estimated sport fish populations.
Assesrment of life-of-the-plant offects on fishes near PIPJP is complicated by a number of interacting f actors.
A balanced indigenous species of fish is multi-aged and fluctuates in relation to variability of year-class strengths, g.
exploitation, natural mortality, and density-dependent mechanisms.
Year-class strength is determined primarily by Ibp abiotic factors, especially water temperature regimes, during spawning and early development stages.
Exploitation is eJten the major source of mortality in adult fish.
Surplus production is the substainable yield or production of new weight by a fishable stock, plus recruits added to it, less what is lost to natural mortality (Ricker 1975).
In a discrete population, surplus production will increase as exploitation increases until the total rate of exploitation from fishing and power plants reduces surplus production below the level needed to sustain the population (McFadden 1975).
McFadden's hypothetical model shows that a population will not decline when exploitation from power plants and fishing in less than 40 percent per year.
k 262 1
---u----
-ywrT
y, When the Oneida Lake walleye population was subjected to Yb exploitation of approximately 40-50 percent in one year, it exhibited high growth rates and population levels in sub-i sequent years (Forney 1967).
Adult walleyes in Lake Erio 4
showed no decline when subjected to 70-78 percent exploitation per year during 1962-1966 (Regier et al. 1969).
Iligh rates of exploitation resulted from heavy fishing pressure in Lake Erie and low abundance of forage fish in other lakes (Forney 1976, Moyle 1949).
These studies suggest that j
fairly high rates of exploitation will not cause a sustained decline if year class formation and recruitment are normal.
I Additional exploitation associated with operation of a power plant would represent a relatively minor source of mortality in the long-term fluctwitions of upper Misaissippi River fish populations.
Even in the immediate plant area, entra!runent and impingement losses may be masked due to the great mobi;ity of fish in the PINGP area.
b l
y 2ca