ML070160217

JAFNPP - SEIS Web Reference - Ross and Dunning 1996

ML070160217
Person / Time
Site:	FitzPatrick
Issue date:	12/31/1996
From:	Dunning D, Kenna M, Menezes J, Ross Q, Tiller G New York Power Authority, Sonalyst
To:	Office of Nuclear Reactor Regulation
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Download: ML070160217 (12)

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Nnrth American Journal of Fisheries Management 16:548-559. 1996 O Copyright by the American Fisheries Society 1996 Reducing Impingement of Alewives with High-Frequency Sound at a Power Plant Intake on Lake Ontario QUENTIN E. ROSS AND DENNIS J. DUNNING New York Power Authority 123 Main Street. White Plains, New York 10601. USA JOHN K. MENEZES, MARK J. KENNA, JR., AND GARY TILLER Sonalysts. Inc.. 215 Parkway North. Waterford. Connecticut 06385. USA Abstract.From April 22 through July 20, 1993, we conducted a follow-up study to confirm that high-frequency broadband sound (122-128 kHz) at a source level (in decibels fdB] in reference to 1 lxPa) of J90 dB reduced the impingement of alewives Alosa pseudoharengus at the James A.

FitzPatrick Nuclear Power Plant (JAF), located on Lake Ontario near Oswego, New York. During the first full-scale test in 1991, the sound field covered only the front of the JAF intake. In this second full-scale test, the sound field included the top, sides, and rear of the JAF intake to prevent fish from approaching the intake from those directions when the JAF reactor was shut down and the hot water discharge, located 57 m offshore from the intake, disappeared. Our study also provided the opportunity to evaluate the effectiveness of the deterrent system during a mass die-off of alewives that occurred in Lake Ontario during late spring and early summer in 1993. We used a before-after-control-impact pairs (BACIP) design to test and quantify the effectiveness of the deterrent system. The new sound field reduced the impingement of alewives by 81-84% during a year following an unusually cold winter and should reduce impingement by 87% during most years.

The stocking of salmonids that began in the ear- rates were initiated in 1993 with the goal of sta-ly 1970s in Lake Ontario (Jones et al. 1993) gen- bilizing predator demand at 50% of the prey pro-erated a major sport fishery with considerable eco- duction by 1996 (Schneider and Schaner 1994).

nomic benefits (Talhelm 1988). This valuable fish- However, the alewife population in Lake Ontario ery is primarily dependent upon a single forage suffered what appeared to be the highest mortality species, the alewife Alosa pseudoharengus (Brandt observed in 10 years in the late spring of 1993 and 1986; Elrod and O'Gorman 1991). However, ale- is presently considered to be threatened (Schneider wife populations in Lake Ontario experience high and Schaner 1994).

mortality during or following unusually cold win- As the concern over alewife production in-ters (O'Gorman and Schneider 1986; Bergstedt creased, the New York State Department of En-and O'Gorman 1989) and historically have exhib- vironmental Conservation (DEC) sought greater ited periodic mass declines (Scott and Crossman protection for alewives in Lake Ontario from an-1973). This instability in alewife production has thropogenic sources of mortality, including power been compounded by high salmonid stocking rates plants. There are eight power plants along the New that have pushed piscivore densities in Lake On- York shoreline of Lake Ontario with a combined tario to record levels (Leach et al. 1987). In 1991, cooling-water flow of about 290 m3/s at full power.

the predator demand in Lake Ontario was esti- In response to DEC's concern, the New York Pow-mated to be equal to the total annual production er Authority reviewed the mitigation technologies of pelagic prey species (Schneider and Schaner available for reducing impingement of alewives on 1994), and simulation modeling suggested that a the intake screens at power plants and temporarily 25% increase in winter-related mortality would installed and tested an acoustic deterrent system cause the alewife population to crash (Jones et al. at the James A. FitzPatrick Nuclear Power Plant 1993). The fact that the alewife population in Lake (JAF), located on Lake Ontario (Ross et al. 1993).

Michigan experienced a massive decline in the ear- This electronic system produced intense (190 deci-ly 1980s that was followed by a collapse of the bels [dB] measured 1 m from the source and ref-fishery for chinook salmon Oncorhynchus tshaw- erenced to 1 jxPa), high-frequency broadband ytscha (Eck and Wells 1987) heightened concern (122-128 kHz) sound and was specifically de-about the sustainability of alewife production in signed to repel alewives from the JAF intake Lake Ontario. Reductions in salmonid stocking (Dunning et al. 1992). When ambient water tem-548

REDUCING IMPINGEMENT WITH SOUND 549 peratures were below 13°C, the deterrent system May. The die-off intensified during June and con-was very effective, and the results were consistent tinued into July. We began testing on April 22 and with the avoidance responses expected from a pe- operated the deterrent system continuously until lagic prey species. The system reduced the density July 20.

of fish (number/100 m3) directly in front of the JAF intake by as much as 96%, and the effective- Methods ness of the deterrent system increased as fish den- Test Site sities increased. However, the deterrent system did The James A. FitzPatrick Nuclear Power Plant not cause a significant reduction in fish densities is located on the south shore of Lake Ontario at in front of the JAF intake when ambient water Nine Mile Point, near Oswego, New York. It with-temperatures were 13°C or above. Because most draws water from the lake at up to 23.4 m-Vs of the alewife population moves offshore into deep through a single offshore intake located 274 m water after spawning (Scott and Crossman 1973), north-northeast of the plant in water 7.3 m deep.

Ross et al. (1993) hypothesized that the alewives Water is withdrawn only from the south (shore-remaining in shallow water after temperatures ward) side of the intake to reduce recirculation of reached 13°C were generally in poor condition, heated water from the discharge which is located which made them less responsive to high-frequen- 57 m farther offshore. The velocity through the cy sound. However, if the response of alewives to intake openings is 0.4 m/s. Water flows from the high-frequency sound decreases when their con- intake through a tunnel into the forebay of the plant dition declines, the deterrent system may not be where traveling screens remove fish and debris be-effective when it is needed most, such as after an fore the water circulates through the cooling sys-unusually cold winter when alewives are in poor tems of the plant. Fish and debris, impinged on condition (O'Gorman and Schneider 1986). the traveling screens, are washed off and collected Ross et al. (1993) found that the deterrent sys- in a basket. The discharge tunnel extends into the tem had little effect on impingement in 1991 when lake and forks; one branch heads east, and the other the JAF reactor was shut down and no hot water heads west, nearly parallel to the shoreline. Heated was being discharged through the 236-m-long dif- water is discharged from each branch tunnel fuser located on the bottom, 57 m offshore from through three high-velocity diffuser heads, spaced the intake. The acoustic field generated by the de- 45.7 m apart and consisting of paired 0.76-m dis-terrent system covered only the open, shoreward- charge nozzles that are directed away from shore.

facing side of the JAF intake. Ross et al. (1993) The total length of the diffuser system is 236 m, hypothesized that the hot-water discharge formed and the depth of the diffuser heads ranges from a thermal barrier that prevented alewives from ap- 7.0 m for the most easterly head to 8.5 m for the proaching the rear of the intake when the reactor most westerly head. The exit velocity of the water was operating. Therefore, when the reactor shut from the diffusers is 4.3 m/s and the discharge down, the thermal barrier disappeared, enabling causes turbulence that reaches all the way to the alewives to approach the rear of the intake and surface when JAF is at full reactor power. The swim along its top and sides to the front, where temperature of the discharge when JAF is at full the opening is located, without encountering the power is 17.5°C higher than the temperature of the sound field. water drawn into the intake. When the JAF reactor We conducted a full-scale follow-up study in was starting up, shutting down, or shut down dur-1993. To prevent fish from approaching the rear ing our study, the flow of water through the plant of the JAF intake and to test the thermal barrier was reduced by about 33%, and the difference be-hypothesis, we increased the number of transduc- tween the intake and discharge temperatures ers in the array used by Ross et al. (1993) so that ranged from 0 to 6°C.

high-frequency sound was produced on top, along the sides, and in back of the intake, as well as in Control Site front. We were able to assess the effectiveness of The Nine Mile Point Unit 1 Nuclear Power Plant the deterrent system before and during a mass die- (NM1) is located 914 m due west of JAF and with-off of alewives during this follow-up study be- draws water from the lake at up to 16.9 m3/s cause the winter of 1992-1993 was colder than through a single offshore intake located 259 m average and produced the first late-spring die-off northwest of the plant in water 7.5 m deep. Water observed since 1984 (Schneider and Schaner is withdrawn from all sides of the intake. The ve-1994). Dead alewives were first observed in late locity through the intake openings is 0.5 m/s. Wa-

550 ROSS ET AL.

2.5m

• WR)EBEAM(1tt1(1ft3)

ADDITIONAL WIOEBEAM (1W)

NARROWBEAM (1W1,1993)

FIGURE I.Location of the wide-beam and narrow-beam transducers of the deterrent system at the intake structure of the James A. FitzPatrick Nuclear Power Plant (JAF) during 1991 and 1993.

ter flows from the intake through a tunnel into the Ross et al. (1993) and produced a minimum sound forebay of the plant where traveling screens re- pressure level (SPL) at 1 m from the transducers move fish and debris before the water circulates of 190 dB in a frequency band from 122 to 128 through the cooling systems of the plant. Fish and kHz. (As in Burdic [I984J, all SPLs are given as debris impinged on the traveling screens are decibels referenced to 1 jiPathat is, 190 dB de-washed off and collected in a basket. Heated water notes 190 dB//u,Pa). In addition, four wide-beam returns to Lake Ontario through a low-velocity (1.2 transducers were installed on the top and sides of m/s) multiport (six) discharge located 102 m north- the intake, and a fifth wide-beam transducer was northwest of the plant in water 5.2 m deep, inshore mounted on a tripod on the lake bottom at the back and west of (he NM1 intake. At full reactor power of the intake structure to ensonify the back, sides, the temperature of the discharge from NM1 is and top of the intake.

17.3°C higher than the temperature of the water The sound fields produced by the five new trans-drawn into the intake. ducers did not overlap as much as those from the Impingement collections from NM1 should pro- 20 transducers that were mounted on the front of vide a good control for those at JAF because the the intake. However, given the sensitivity of ale-NMJ intake is close (1.3 km) to the JAF intake wives to high-frequency sound, the presence of the but is beyond the effective range of the deterrent five new transducers was expected to generate a system (80 m). Furthermore, the large-scale cir- detectable reduction in impingement at JAF when culation in Lake Ontario is counterclockwise, gen- the reactor was shut down and there was no ther-erating a current that flows from west to east in a mal barrier behind the intake. Sound was produced relatively narrow band along the south shore. for a 0.5-s duration every 1.5 s. Upon installation Thus, schools of alewives moving through the and before removal of the system, hydroacoustic Nine Mile Point area with this current pass the measurements were taken to verify the design control intake before encountering the test intake. source levels and beam patterns transmitted.

Deterrent System Impingement Collections The acoustic deterrent system consisted of an Paired, 24-h impingement samples were col-array of electronic transducers, connecting ca- lected at JAF and NM1. The samples at NM1 were bling, impedance-matching devices, power ampli- collected between 1200 and 1300 hours0.015 days <br />0.361 hours <br />0.00215 weeks <br />4.9465e-4 months <br />. Those at fiers, a signal generator, and a personal computer JAF were collected between 1300 and 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br />.

for control and data logging. The transducer array This 2-h period was selected because the abun-contained 16 narrow-beam and 9 wide-beam trans- dance of alewives in the vicinity of the two power ducers (Figure 1). The 20-transducer array on the plants was generally low during the middle of the front of the intake was the same as that used by day (Ross et al. 1993) and the interruption in the

REDUCING IMPINGEMENT WITH SOUND 551 collection of impinged fish was not likely to con- TABLE 1.Number of alewives impinged on the intake found the daily totals. screens of the James A. FitzPatrick Nuclear Power Plant (JAF) and the Nine Mile Point Nuclear Station Number 1 (NM1) on those days when high-frequency sound was pro-Statistical Analyses duced and when it was not and when only the NM 1 reactor Effectiveness of the deterrent system.A before- was at or near full power, and the temperature of Lake Ontario was less than 13°C. Samples were partitioned into after-control-impact pairs (BACIP) design (Stew- days when the number of alewives impinged at NM 1 ex-art-Oaten et al. 1986) was used to test the differ- ceeded 1,000 (high-abundance block) and days when the ences among selected sets of paired impingement number was between 100 and 999 (low-abundance block).

samples. An observation in this design is the dif-Sound produced Sound not produced ference between the impingement counts at JAF (the impact site) and NM1 (the control site) on the Date JAF NM1 Date JAF NM1 same day. The "after" samples consist of the High abundance block paired daily impingement counts collected during 1993 1985 the period from late April through late July in 1993 Apr 23 595 8,400 Apr 26 1,692 10,424 Apr 24 183 10,716 Apr 28 1,652 10,224 when the deterrent system was operating. The "be- Apr 25 580 4.388 Apr 29 1.850 8.416 fore" samples consist of paired daily impingement Apr 26 276 1,438 Apr 30 3.312 15.464 counts collected during the same period in years Apr 27 692 1.291 May 1 5.236 10.136 Apr 28 183 1.423 May 2 6,608 15,952 when the deterrent system was either not installed May 28 1,618 11.500 May 5 8.884 2,688 (1981, 1985-1987, and 1994) or was installed but May 29 590 5.292 May 6 7,688 8.704 not turned on (1991). The installation and removal May 7 5,032 9,000 May 8 4,412 12,4%

of the high-frequency transducers did not affect May 9 9,488 9.780 the flow patterns or physical features at the JAF May 10 6.732 8.828 intake. Thus, the fact that some of the "before" May 11 6.864 6.380 samples were collected after the "after" samples May 13 11,788 9.628 May 14 7,316 11,364 should not affect their validity as controls. How- May 15 10.804 9,762 ever, it does make "before" an inappropriate label. May 16 9,124 9.724 Therefore, we used "sound not produced" for May 30 4.168 5,740 May 31 3.868 4.796 "before" and "sound produced" for "after" in Low-abundance block our tables.

1993 1991 We used two-sample /-tests for determining Apr 21 78 138 May 16 182 947 whether the average daily difference in the "after" Apr 22 172 579 May 17 167 467 samples was significantly different from that in the May 18 56 491 May 19 214 577 May 19 31 376 May 20 189 582 "before" samples. These tests assume normality, May 20 48 608 May 21 200 536 additivity, and independence. We transformed the May 21 55 670 May 22 138 439 daily counts (log^ c or log,, c + 1 when zeros were May 22 34 626 May 23 102 401 present) and used modified /-tests (Statistix 4.1; May 23 40 844 May 25 76 391 May 24 26 341 Analytical Software 1994) to protect against vio- May 25 34 207 lations of the normality assumption (Stewart-Oat- May 26 75 487 en et al. 1992). May 27 88 547 Before testing the remaining assumptions, we separated the paired samples into two groups, those collected when the JAF reactor was shut the JAF forebay and generated transient surges in down and those collected when it was at or near impingement.

full power. We used the first group of samples to When the JAF reactor was shut down, the num-determine the effectiveness of the new transducer bers of alewives impinged at NM1 ranged from array. We used the second group to determine the 138 to 15,952 (Table I). To reduce variance het-effectiveness of the deterrent system after the un- erogeneity and the effects of seasonal changes in usually cold winter of 1992-1993. Only those sam- behavior that might be associated with spawning, ples collected on days when the JAF reactor was we partitioned the samples into a high-abundance at or near full power were used in the second group block that included all days when the number of because increases in cooling water flows associ- alewives impinged was at or above 1,000 at NM 1, ated with rising power levels changed the mag- and a low-abundance block that included all days nitude and distribution of the water currents within when the number of alewives impinged was be-

552 ROSS ET AL.

tween 100 and 999 at NM1 (Table 1). The high- TABLE 2.Number of alewives impinged on the intake abundance block involved primarily prespawning screens of the James A. FitzPatrick Nuclear Power Plant (JAF) and the Nine Mile Point Nuclear Station Number 1 and spawning alewives; the low-abundance block (NM 1) on those days when high-frequency sound was pro-involved alewives impinged primarily after the pe- duced and when it was not and when both the JAF and riod of peak impingement when spawning prob- NM 1 reactors were at or near full power, and the temper-ably occurred. ature of Lake Ontario was less than I3°C. Samples were When the JAF reactor was at or near full power, partitioned into days when the number of alewives im-ambient water temperatures ranged from 6 to 23°C. pinged at NM1 exceeded 1,000 (high-abundance block)

During the 1991 study, the response to high-fre- and days when the number was between 95 and 999 (low-abundance block.

quency sound disappeared when water tempera-tures were 13°C or above (Ross et al. 1993). There- Sound produced Sound not produced fore, we divided the samples collected when the Date JAF NMI Date JAF NMI JAF reactor was at or near full power into two High-abundance block groups, one consisting of samples collected when 1993 1987 water temperatures were below 13°C and the other Apr 30 495 2.731 May 6 1,336 1,170 consisting of samples collected when water tem- May 2 749 3,730 May 7 414 1.340 peratures were 13°C or above. May 3 465 1,523 May 8 1,336 1.0%

May 4 254 1.653 May 10 2.838 2.568 When water temperatures were below 13°C and May 5 266 1,635 the JAF reactor was at or near full power, the num- May 7 477 2,135 1994 ber of alewives impinged at NM1 ranged from 95 May 8 164 4.906 May 7 1,920 1.578 May 9 100 1.597 May 13 3.024 12,960 to 12,960 (Table 2). To reduce variance hetero- May 10 318 6,841 May 14 6,450 7,332 geneity and the effects of seasonal changes in be- May 11 218 1.594 May 15 4.670 2,232 havior that might be associated with spawning, we May 12 241 1.894 May 21 2,936 2.771 again partitioned the samples into a high-abun- May 13 286 3.091 May 22 5,387 3,487 May 14 166 1,075 May 27 9,450 2,241 dance block that included all days when the num-Low-abundance block ber of alewives impinged was at or above 1,000 1993 1987 at NM1 and a low-abundance block containing all May 1 303 950 May 12 489 690 days when the number of alewives impinged was May 6 312 824 May 13 332 597 between 95 and 999 at NM1 (Table 2). The high- May 15 161 699 May 14 189 322 May 16 191 667 May 17 99 192 abundance block involved prespawning and May 17 155 556 May 21 88 187 spawning alewives; the low abundance block in- Jun 2 48 222 May 22 58 202 volved alewives impinged after the period of peak Jun3 24 223 May 27 135

• 102 impingement. Jun 4 36 133 Jun 5 36 360 1994 The samples collected when ambient water tem- Jun 6 54 211 May 8 308 129 peratures were 13°C or above and the JAF reactor Jun 7 89 244 May 16 1,421 680 was at or near full power included only alewives Jun 8 55 136 May 18 187 180 Jun 9 51 256 May 19 307 372 impinged after the period of peak impingement and Jun 10 123 268 May 26 226 95 impingement counts at NM1 ranged from 0 to 319 Jun 11 151 304 (Table 3). We did not partition this set of samples. Jun 12 117 228 The assumption of additivity requires that the Jun 13 88 268 expected difference between the impact and con-trol sites be the same for all dates. We tested for additivity within each abundance block and within greatly decreasing the contribution of the test site the high-temperature group by correlating the dif- to the sum of the impingement counts. Thus, the ferences between, and the sums of, the transformed magnitudes of the difference between the counts paired daily impingement counts from the two from the two sites and the sum of the counts from sites for the "sound not produced" treatment (a the two sites would both be dependent upon the significant correlation indicated the presence of counts at NM 1.

nonadditive effects). We did not test for additivity Results from /-tests may be invalid when first-within the "sound produced" treatment because order autocorrelations are greater than 0.30 (Stew-the deterrent system was expected to generate a art-Oaten et al. 1992). We tested for independence significant correlation between the sums of the by estimating the first-order autocorrelations paired daily impingement counts from the two among the differences (generated from trans-sites and the differences between the pairs by formed data) for the treatments within each block.

REDUCING IMPINGEMENT WITH SOUND 553 TABLE 3.Number of alewives impinged on the intake came from alewives that were resident in shallow screens of the James A. FitzPalrick Nuclear Power Plant water. We hypothesized that these fish were in poor (JAF) and the Nine Mile Point Nuclear station Number I condition, which prevented them from moving off-(NM1) on those days when the high-frequency sound was produced and when it was not, when both the JAF and shore into deeper water. If these fish were unable NM1 reactors were at or near full power, and when the to leave shallow water, they should have been ex-temperature of Lake Ontario was >13°C. posed to the high frequency sound field more than the prespawning or spawning alewives were. Thus, Sound produced Sound not produced if acclimation to high-frequency sound were to Date JAF NMI Date JAF NMI occur, it should have been most apparent with these 1993 1981 fish. We tested for acclimation in these fish by Jun 14 147 118 Jul 31 373 92 regressing the daily differences between the trans-Jun 15 119 226 1985 Jun 16 132 306 Jul 25 232 17 formed impingement counts at JAF and NMI Jun 17 114 300 1986 against time. A significant negative slope would Jun 18 113 129 Jul 2 472 22 indicate that alewives became less responsive to Jun 19 90 151 Jul 25 269 10 high-frequency sound over the 36-d period.

Jun 20 123 319 1987 Jun 21 102 27 Jun 17 140 10 We used an alpha level of 0.05 in all tests of Jun 22 116 120 Jun 26 178 75 assumptions, the test for acclimation when water Jun 23 99 117 Jul 2 371 7 temperatures were 13°C or above, and the test of Jun 24 84 82 Jul 10 476 4 Jun 25 107 55 Jul 20 68 2 the effectiveness of the deterrent system when wa-Jun 26 99 17 Jul 30 15 1 ter temperatures were 13°C or above. To protect Jun 27 101 66 1994 against inflation of alpha errors in our evaluation Jun 28 79 153 Jun 14 144 29 Jun 29 67 84 Jun 23 63 2 of the effectiveness of the new transducer array Jun 30 170 54 Jun 28 83 2 and to confirm the effectiveness of the deterrent Jul 1 102 116 Jul 5 49 1 system when the JAF reactor was at or near full Jul 2 227 274 Jul 13 10 0 power, we used an alpha level of 0.025 for the /-

Jul 3 83 48 Jul 4 128 86 tests in each block.

Jul 5 84 164 We estimated the effectiveness of the deterrent Jul 6 29 68 system using the equation Jul 7 21 44 Jul 8 27 100 percent change = (*on-off _ l) x 100, Jul 9 25 35 Jul 10 18 49 where "on" and "off" are the means from a BA-Jul 11 14 11 Jul 12 10 103 CIP comparison. Under the null hypothesis, the Jul 13 II 21 expected difference between the two means is Jul 14 1 6 zero, resulting in a 0% change. If the deterrent Jul 15 55 249 system reduced the impingement of alewives at Jul 16 65 141 Jul 17 13 14 JAF, the percent change was negative.

Jul 18 0 63 Analysis of the control data.If alewives avoid-Jul 19 1 4 ed high water temperatures near the JAF discharge, we expected that they would do the same at the NMI discharge. However, unlike the effect hy-The time series in all of the samples collected when pothesized for JAF (a reduction in impingement),

sound was not produced were interrupted and this response should result in an increase in im-could not be tested. There were time series within pingement at NMI because the location of the in-four of the five samples collected when sound was take relative to the discharge was the opposite of produced that were long enough to test. However, that at JAF. The NMI discharge is located inshore three of these time series were relatively short (in- and west of the NMI intake, and alewives at-volving 15 or fewer observations) and the power tempting to avoid the NMI discharge by moving of these tests was probably low. offshore would be carried into the vicinity of the We obtained our longest test series, 36 d, during NMI intake by the prevailing west to east current the period when water temperatures were 13°C or in the Nine Mile Point area. Intake flow also affects above and alewife abundance was low. Because the numbers of fish impinged at a given site, and most alewives move offshore into deeper and cool- we expected the number of alewives impinged at er water after spawning, we suspected that the JAF to be higher than that at NMI when both smaller numbers impinged during June and July power plants are at or near full power. Therefore,

554 ROSS ET AL.

we expected to observe the greatest effect of the reduce the serial dependence. The sample size de-discharge at NM1 when the JAF reactor was shut creased from 12 to 7.

down, at which time the intake flows at the two BACIP tests.When alewife abundance was sites were comparable in this study. high, the deterrent system significantly reduced the We used the mean differences observed between number of alewives impinged at JAF (P = 0.001);

the transformed impingement counts at the test and the estimated reduction was 81%. When alewife control sites (always subtracting the transformed abundance was low, the deterrent system had no counts at NM1 from the transformed counts at significant effect (P = 0.065); the estimated re-JAF) when no sound was produced to determine duction was 51%.

the effect of the NM1 discharge on the number of alewives impinged at NM1. We used one-sample Effectiveness of the Deterrent System after an r-tests and tested each mean difference against the Unusually Cold Winter (at Water Temperatures null hypothesis that the average difference be- below 13°C) tween the transformed impingement counts from Tests for additivity.The test for additivity was the two sites was equal to 0 when no sound was not significant in either the high-abundance block produced. We used an alpha level of 0.05 for each or the low-abundance block (Table 2). The cor-test. relation between the difference in the transformed daily impingement counts and the sum of the trans-Results formed daily impingement counts from JAF and Reliability of the Deterrent System NMI when sound was not produced was 0.163 (P The deterrent system operated continuously for = 0.631) in the high-abundance block and 0.238 90 d. During this time, no systems or components (P = 0.456) in the low-abundance block.

failed. All validation measurements, taken with the Tests for independence.The assumption of in-receive hydrophone in the maximum response axis dependence could not be tested in the "sound not of each transducer, met or exceeded design values produced" treatments because the time series were (a level of 170 dB or above at 10 m). None of the too short. In the "sound produced" treatments, we transducers, unlike the other underwater surfaces inserted 2 d from the low-abundance block (May at or near the JAF intake, were fouled by zebra 1 and May 6) into the time series from April 30 mussels Dreissena polymorpha. Cladophora spp., to May 14 in the high-abundance block to generate or other aquatic organisms. a longer time series for testing the autocorrela-tions. In the low-abundance block, the time series Effectiveness of the New Transducer Array from June 2 through June 13 was long enough to (at Water Temperatures below I3°C) lest. The first-order autocorrelation in the low-Tests for additivity.The test for additivity was abundance block was less than 0,30 (0.27), but in not significant in either the high-abundance block the high-abundance block it was greater than 0.30 or the low-abundance block (Table 1). The cor- (0.42). An increase in the response to the deterrent relation between the difference in the transformed system occurred after May 7 based on the differ-daily impingement counts and the sum of the trans- ences between JAF and NMI in the high-abun-formed daily impingement counts from JAF and dance block (Table 2). From April 30 through May N M I when sound was not produced was 0.376 (P 6, water temperatures were below 9°C; from May

- 0.113) in the high abundance block and 0.310 7 through May 14, water temperatures were be-(P = 0.454) in the low-abundance block. tween 9 and 11°C, except for May 8. Smith (1985)

Tests for independence.The time series in the reported that alewives begin spawning at 11°C, and high-abundance block and in the "sound not pro- the heightened response to the deterrent system duced" treatment in the low-abundance block were was probably caused by the increased activity as-too short to test for autocorrelations. The first- sociated with the onset of spawning. We attempted order autocorrelation for the treatment that could to avoid the confounding effects of this change in be tested was greater than 0.30 (0.58). An inspec- behavior by testing the impingement samples col-tion of the differences between the impingement lected before May 8 separately from those col-counts from the test and control sites revealed a lected after May 7 (Table 2).

consistent 2-d pattern (Table 1). The second-order BACIP tests.The deterrent system significant-autocorrelation was very small (0.05). Therefore, ly reduced the number of alewives impinged at we used the average counts for each 2-d interval JAF in both blocks. In the high-abundance block, as the independent observations in this data set to the estimated reduction was 81 % (P < 0.001) prior

REDUCING IMPINGEMENT WITH SOUND 555 to May 8 and 92% (P < 0.001) after May 7. In to east through the Nine Mile Point area. If these the low-abundance block, the estimated reduction schools avoided the hot water from the NM1 dis-was 68% (P < 0.001). charge as they did at JAF (Ross et al. 1993), some Effectiveness of the Deterrent System When alewives would be deflected offshore toward the Water Temperatures Were I3°C or Above NM1 intake, which could increase the numbers of alewives impinged at NM1. This hypothesis is Tests for additivity.The test for additivity was consistent with the differences observed between not significant (Table 3). The correlation between the transformed impingement counts at JAF and the difference in the transformed daily impinge- NM1 when water temperatures were below 13°C ment counts and the sum of the transformed daily and no sound was produced. When both sites were impingement counts from JAF and N M I under the at or near full power, the transformed impingement "sound not produced" treatment was -0.223 (P counts at JAF were not significantly greater than

= 0.425). those at NM1, in spite of the greater intake flows Tests for independence.The assumption of in- at JAF. When the JAF reactor was shut down, the dependence could not be tested in the "sound not transformed impingement counts at NM 1 were sig-produced" treatment because the time series was nificantly greater than those at JAF, in spite of the too short. In the "sound produced" treatment, the fact that the intake flows were comparable at the time series was long enough to test. The first-order two sites.

autocorrelation was less than 0.30 (0.26). When water temperatures were 13°C or above, BACJP test.The deterrent system significantly the hypothesized effect of the NM1 discharge on reduced the number of alewives impinged at JAF impingement at NM1 disappeared. When both when water temperatures were 13°C or above (P sites were at or near full power, the transformed

< 0.001): the estimated reduction was 96%. impingement counts at JAF were significantly Acclimation test.The regression of the daily greater than those at NM 1, which is consistent with differences between the transformed counts at JAF the difference between the intake flows at the two and NM 1 against time during this 36-d period was sites. We believe that the effect of the NM1 dis-significant (R2 = 0.184; P = 0.009: slope = charge on impingement at NM 1 was not detectable

-0.04). when water temperatures were 13°C or above be-Analysis of Control Data cause large schools of alewives stopped moving When water temperatures were below 13°C and through the Nine Mile Point area. Small schools both sites were at or near full power, the mean of alewives were more likely to move away from differences between the transformed impingement the NM1 discharge without coming close to the counts at JAF and NM 1 when no sound was pro- NM 1 intake than large schools.

duced were not significantly different from 0 in The disappearance of large schools of alewives both the high-abundance (P = 0.843) and low- from the Nine Mile Point area after spawning also abundance (P = 0.538) blocks. When water tem- provides an explanation for another result that only peratures were below 13°C and the JAF reactor occurred when water temperatures were 13°C or was shut down, the mean difference between the above, an increase in the numbers of alewives im-transformed impingement counts from the two pinged at NM1 when the deterrent system was op-sites observed when no sound was produced was erating. At temperatures below 13°C, alewives re-negative and significantly different from 0 in both pelled by the deterrent system in the direction of the high-abundance (P = 0.010) and low-abun- the N M I intake would encounter many large dance (P < 0.001) blocks. When water tempera- schools of alewives that were moving through the tures were 13°C or above and both sites were at Nine Mile Point area in the opposite direction, i.e.,

or near full power, the mean difference between west to east. The alewife is a schooling species the transformed impingement counts from the two and the alewives swimming west away from the sites observed when no sound was produced was JAF intake were more likely to have joined a large positive and significantly different from 0 (P < school swimming east than they were to have con-0.001). tinued swimming west through it. As a result, all alewives repelled by the deterrent system would Discussion eventually join the west to east flow of alewives Analysis of Control Data through the Nine Mile Point area. However, when When water temperatures were below 13°C. small scattered schools of alewives were moving many large schools of alewives moved from west through the Nine Mile Point area, alewives swim-

556 ROSS ET AL.

ming west away from the JAF intake would have the unusually cold winter of 1992-1993 did not a lower probability of encountering a school of affect the responsiveness of spawning alewives.

alewives swimming east and be more likely to There are no data from 1991 that can be directly reach the NM1 intake. Ross et al. (1993) found compared to the BACIP estimate generated from that large schools were more common when water prespawning fish (81%). The remaining compari-temperatures were below 13°C; small schools were son between 1991 and 1993 estimates involves more common when water temperatures were 13°C samples collected when alewife impingement was or above. Thus, the probability of reaching the declining and water temperatures were below NM1 intake would be higher when water temper- 13°C. We did not calculate a BACIP estimate from atures were 13°C or above. the impingement data collected in 1991 during this The low flow of alewives through the Nine Mile period because the JAF reactor was shut down. We Point area when water temperatures were 13°C or believe that the BACIP estimate would be biased above and the accumulation of responsive ale- under these conditions because the deterrent sys-wives in the area around the NM1 intake when the tem covered only the front of the JAF intake in deterrent system was operating would also in- 1991. When the JAF reactor was shut down, more crease the relative abundance of unresponsive ale- fish were sampled with hydroacoustics than by im-wives in the area around the JAF intake, account- pingement collections. Therefore, the effect of ing for the slight acclimation that occurred when small numbers of fish from the rear of the intake water temperatures were 13°C or above and pro- probably had less of an effect on the estimate of viding an explanation for the absence of a statis- the effectiveness of the deterrent system generated tically significant treatment effect in the 1991 from the hydroacoustic data. So, we converted the study when water temperatures were 13°C or above diel estimates of the percent reduction in the den-(Ross et al. 1993). sity of fish in front of the JAF intake when the JAF reactor was shut down in 1991 into an esti-Effect of the Unusually Cold Winter of mate of the percent reduction over a 24-h period.

1992-1993 The resulting percent reduction over a 24-h period was 86%. This estimate included fish that ap-We evaluated the effect of the unusually cold proached from the rear of the JAF intake into the winter of 1992-1993 by comparing the results area monitored in front of the intake, and thus, was from the 1991 and 1993 studies. In 1991, both JAF probably biased low. The 24-h estimate when the and NM1 were at full power during the first week JAF reactor was at full power, which was unbiased in May (Ross et al. 1993). The most comparable because the thermal discharge behind the JAF in-data set from 1993 is the high-abundance block take blocked fish approaching from the rear of the when both JAF and NM 1 were at or near full power intake, was 91%. Thus, the bias generated when and lake temperatures were generally between 9 the JAF reactor shut down could be as much as 5 and 11°C. We could not use impingement data percentage points. In 1993, when alewife abun-from 1991 because the sample size was too small dance was low, water temperatures were below under these conditions. To provide a direct com- 13°C, and both JAF and NM1 were at or near full parison between the 1993 BACIP estimate derived power, the BACIP estimate was 68%. The 18 point from 24-h impingement samples and the 1991 difference between these two estimates suggests study, we converted the diel estimates of the per- that the unusually cold winter of 1992-1993 af-cent reduction in the density of fish in front of the fected the responsiveness of alewives during the JAF intake from Ross et al. (1993) into estimates postspawning period when alewife impingement of the percent reduction over a 24-h period by was declining and water temperatures were below assigning equal weights to the number of hours in 13°C.

each diel period and to the average density of fish observed in front of the JAF intake during each Effectiveness of the New Transducer Array diel period. The daytime period was twice as long The new transducer array installed on the sides as the nighttime period but the density of fish ob- and back of the intake was at least as effective as served during the day was more than five times the one in front of the intake, based on the 81%

lower than that observed at night. The BACIP es- BACIP estimate when alewife abundance was timate of the effectiveness of the deterrent system high, water temperatures were 8°C or less, and (92%) was almost identical to the 24-h estimate both power plants were at or near full power and (91%) from the 1991 study, which suggests that when the JAF reactor was shut down under the

REDUCING IMPINGEMENT WITH SOUND 557 same conditions. The two samples collected on would increase. The differences among the dates May 28 and 29, when water temperatures were when the three low-abundance samples were col-below 13°C, the JAF reactor was shut down, and lected and the differences among the BACIP es-alewife abundance was high, confirmed that the timates generated from these samples are consis-sound field behind the JAF intake was at least as tent with this hypothesis. For example, most of the effective as the one in front of the intake. These test samples collected when water temperatures samples were collected when there were high were below 13°C, alewife abundance was low, and winds from the north, which should have moved the JAF reactor was shut down were collected over postspawning fish from offshore waters directly the period from May 18 through May 27 (Table into the rear sound field. The differences between 1), right after the period when spawning probably the impingement counts at JAF and NMl on these occurred. The BACIP estimate from this test was two dates were close to the average value for the 51%. Most of the test samples collected when wa-entire high-abundance block. The similarity be- ter temperatures were below 13°C, alewife abun-tween the late April and late May samples also dance was low, and both JAF and NM1 were at or indicates that the offshore population of post- near full power were collected either during early spawning alewives during late May was as re- May before spawning or during June (Table 2),

sponsive as prespawning alewives were during late after the beginning of the mass die-off of alewives April and early May. in Lake Ontario in 1993 reported by Schneider and The new transducer array appeared to be less Schaner (1994). The BACIP estimate from this test effective than the one in front of the intake when was 68%. All of the test samples collected when abundance of alewives was low and water tem- water temperatures were 13°C or above, alewife peratures were below 13°C. This result could be abundance was low, and both JAF and NMl were due to areas of low sound pressure within the at or near full power were collected after mid-June acoustic field along the sides, rear, and top of the (Table 3). The BACIP estimate from this test was intake that permitted small schools of fish to ap- 96%.

proach the intake. The acoustic coverage around If the underlying cause is the failure of severely the JAF intake was not uniform. In front of the stressed alewives to move offshore after spawning, intake, there was more overlap among the beam the comparison of the 24-h estimate of the effec-patterns of the transducers than among those along tiveness of the deterrent system in 1991 when wa-the sides, rear, and top of the intake. As the number ter temperatures were below 13°C, alewife abun-of fish in a polarized school decreases (assuming dance was low, and the JAF reactor was shut down similar nearest-neighbor distance), the attention field of the school, i.e., the volume of water within (86%) and the BACIP estimate from the test con-which the school reacts to stimuli, decreases (Nor- ducted under the same conditions in 1993 (51%),

ris and Schilt 1988). Thus, smaller schools of ale- provides another measure of the effect of the un-wives, with their smaller attention fields, may have usually cold winter of 1992-1993. This measure been able to fit into the areas of low pressure sound suggests that the full effect of the unusually cold that larger schools could not. winter was not expressed until after the alewives We believe that a better explanation for the ap- had spawned, which is consistent with the begin-parent reduction in effectiveness of the new trans- ning of the mass die-off of alewives during late ducer array at low abundance was a diminished May.

ability of alewives near the intake to respond. The 24-h estimate of the effectiveness of the When abundance was low, alewives moved on- deterrent system from 1991 when water temper-shore by the wind event during late May were more atures were below 13°C, alewife abundance was responsive to the deterrent system than those al- low, and the JAF reactor was shut down also pro-ready in shallow water. This explanation suggests vides a conservative estimate of the effectiveness that alewives that had been severely stressed by of the deterrent system on prespawning alewives the unusually cold winter of 1992-1993 did not in 1991 because it was generated from samples move offshore into deeper water as alewives usu- collected immediately after the period when ale-ally do after spawning (Scott and Crossman 1973). wife abundance was high (Ross et al. 1993). The As these fish died or recovered over time, the rel- prespawning BACIP estimates in 1993 (81%) were ative abundance of severely stressed alewives lower than the 24-h estimate from 1991 (86%),

within the shallow water zone would decrease, and which suggests that the unusually cold winter of thus the effectiveness of the deterrent system 1992-1993 slightly reduced the responsiveness of

558 ROSS ET AL.

prespawning alewives to broadband high-frequen- caged fish (Dunning et al. 1992) and later, in the cy sound. field, with fish unaffected by capture and handling (Ross et al. 1993). The effectiveness of a full-scale Overall Effectiveness of the Deterrent deterrent system installed at JAF was confirmed System by our field test which used a primary measure-The average daily water temperature recorded ment variable and an analytical method different at the JAF intake from January through March over from those used by Ross et al. (1993). Collectively, the 13-year period from 1981 through 1993 was these studies would constitute a successful dem-3.1°C. The average daily water temperature during onstration of a new fish protection measure, except this period in 1993 was 1.8°C, well below the for the absence of comprehensive tests at a wide 13-year average. In 1991, the average daily water variety of sites (Tyus and Winter 1992; Cada and temperature during the period from the beginning Sale 1993; OTA 1995). However, we believe that of January through the end of March was close high-frequency broadband sound will be as effec-(3.3°C) to the 13-year average. tive in decreasing the impingement of alewives at We combined the prespawning, spawning, and other sites as it was at JAF if the deterrent sound postspawning estimates from 1993 to generate an field has no holes, background noises do not mask estimate of the overall effectiveness of the deter- the high-frequency signals generated by the de-rent system following an unusually cold winter. terrent system, there are no strong reflections of We used the ratio of the number of alewives im- the high-frequency signals that make it difficult pinged at NM1 during each test to the total number for alewives to determine the location of the impinged at NM1 during all tests in 1993 as a source, and there are no strong currents which pre-weighting factor for the corresponding BACIP es- vent alewives from moving away from the deter-timate. We multiplied each BACIP estimate by its rent sound field. The similarity of our estimates of weighting factor and summed the weighted esti- effectiveness with hydroacoustic and impingement mates to arrive at the estimate of the overall ef- data indicate that hydroacoustic methods can be fectiveness of the deterrent system. The overall used at facilities where a good control site is un-effectiveness of the deterrent system during the available, or the cost is high for collecting exten-1993 study was 81% when the low-temperature, sive time series of paired impingement samples at low-abundance, BACIP estimates were included. control and test sites both before and after the When the low-temperature, low-abundance, BA- installation of a deterrent system.

CIP estimates were replaced by the estimate of Hastings et al. (1996) stated that high-frequency effectiveness for the offshore population of post- sounds, as used at JAF, could potentially damage spawning alewives (81%), the overall effective- the ears of alewives if these fish are exposed to an ness of the deterrent system was 84%. SPL of 180 dB, or even less, for an extended period To generate an estimate of the overall effec- of time. However, they also concluded that short-tiveness of the deterrent system following an av- term stimulation with sound (e.g., minutes) or erage winter, we used the 24-h postspawning es- stimulation when fish are free to leave the sound timate from 1991 (86%) in place of the 1993 pre- field may have little effect on the ear and lateral spawning estimates (81%), the 24-h spawning es- line. Ross et al. (1993) demonstrated that schools timate from 1991 (91%) in place of the 1993 of alewives in front of the JAF intake responded spawning estimate (92%), and the 24-h post- in less than 1 s to high-frequency sound at 156 spawning estimate from 1991 (86%) in place of dB. When fish were swimming toward the front of the 1993 postspawning estimates when water tem- the intake, they reversed direction. When fish were peratures were below 13°C (51% and 68%), the swimming parallel to or away from the front of 1993 estimate (96%) when water temperatures the intake, they continued in those directions.

were 13°C or above, and the weighting factors When the sound was turned off, 2-7 min passed from the 1993 tests. The estimated overall effec- before the density of alewives (number/m 3 ) in tiveness of the deterrent system following a milder front of the JAF intake reached pre-sound levels.

winter is 87%. The average reduction in the density of alewives Electronically produced, intense (190 dB//u,Pa) in front of the JAF intake was 85% during a period high-frequency broadband (122-128 kHz) sound of five weeks when high-frequency sound was pro-consistently produced a strong and directional duced. These results indicate that alewives near avoidance response from healthy alewives in rep- the JAF intake strongly avoided sounds at inten-licated tests under controlled conditions with sities about one-sixteenth the SPL used by Has-

REDUCING IMPINGEMENT WITH SOUND 559 tings et al. (1996) to produce limited and incon- Transactions of the American Fisheries Society 120:

sistent damage to the ears of the oscar Astronotus 290-302.

Hastings, M. C, A. N. Popper, J. J. Finneran, and P. J.

ocellatus, that alewives did not remain in the sound Lanford. 1996. Effect of low-frequency underwater field at JAF for an extended period of time after sound on hair cells of the inner ear and lateral line it was initially produced, and that relatively few of the teleost fish Astronotus ocellatus. Journal of alewives entered the sound field at JAF once it the Acoustic Society of America 99:1759-1776.

was established. Thus, we believe that a well-de- Jones, M. L.. J. F. Koonce, and R. O'Gorman. 1993.

signed deterrent system is not likely to cause dam- Sustainability of hatchery-dependent salmonine fisheries in Lake Ontario: the conflict between pred-age to the ear of alewives that are capable of swim- ator demand and prey supply. Transactions of the ming away from high-frequency sound. American Fisheries Society 122:1002-1018.

Leach, J. H., and five coauthors. 1987. A review of Acknowledgments methods for prediction of potential fish production with application to the Great Lakes and Lake Win-This project was conducted in cooperation with nipeg. Canadian Journal of Fisheries and Aquatic the Water Quality Subcommittee of the Empire Sciences 44(Supplemenl 2):471-485.

State Electric Energy Research Corp. (ESEERCO). Norris. K. S., and C. R. Schilt. 1988. Cooperative so-cieties in three-dimensional space: on the origins of It was funded by ESEERCO (EP 89-30) and the aggregations, flocks, and schools, with special ref-New York Power Authority (NYPA). We thank erence to dolphins and fish. Ethology and Socio-John Holsapple of ESEERCO; Mary Alice Ko- biology 9:149-179.

eneke of EA Engineering, Science, and Technol- O'Gorman, R., and C. P. Schneider. 1986. Dynamics of ogy; Pete Dolan of Sonalysts, Inc.; Hugh Flanagan alewives in Lake Ontario following a mass mortal-of Niagara Mohawk Power Corp.; Lucio Lombar- ity. Transactions of the American Fisheries Society 115:1-14.

dozzi of NYPA; and the staff of the James A. OTA (Office of Technology Assessment). 1995. Fish FitzPatrick Nuclear Power Plant for their assis- passage technologies: protection at hydropower fa-tance. cilities. U. S. Government Printing Office, OTA-ENV-641, Washington, D.C.

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Bergstedt, R. A., and R. O'Gorman. 1989. Distribution Schneider, C. R, and T. Schaner. 1994. The status of of alewives in southeastern Lake Ontario in autumn pelagic prey stocks in Lake Ontario in 1993. New and winter: a clue to winter mortalities. Transactions York State Department of Environmental Conser-of the American Fisheries Society 118:687-692. vation 1994 Annual Report from Bureau of Fish-Brandt, S. B. 1986. Food of trout and salmon in Lake eries Lake Ontario Unit to the Lake Ontario Com-Ontario. Journal of Great Lakes Research 12:200- mittee and the Great Lakes Fishery Commission, Ann Arbor, Michigan.

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Scott, W. B., and E. J. Crossman. 1973. Freshwater Burdic, W. S. 1984. Underwater acoustic system anal-fishes of Canada. Fisheries Research Board of Can-ysis. Prentice-Hall, Englewood Cliffs, New Jersey.

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Cada, G. F, and M. J. Sale. 1993. Status of fish passage Smith, C. L. 1985. The inland fishes of New York State.

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Eck, G. W.. and L. Wells. 1987. Recent changes in Lake Stewart-Oaten, A., W. W. Murdoch, and K. R. Parker.

Michigan's fish community and their probable caus- 1986. Environmental impact assessment: pseudo-es, with emphasis on the role of alewife (Alosapseu- replication in time? Ecology 67:929-940.

doharengus). Canadian Journal of Fisheries and Talhelm, D. R. 1988. Economics of Great Lakes fish-Aquatic Sciences 44(Supplement 2):53-60. eries: a 1985 assessment. Great Lakes Fishery Com-Elrod. J. H.. and R. O'Gorman. 1991. Diet of juvenile mission Technical Report 54.

lake trout in southern Lake Ontario in relation to Tyus, H. M., and B. D. Winter. 1992. Hydropower de-abundance and size of prey fishes, 1979-1987. velopment. Fisheries 17(l):30-32.