FINAL REPORT BIOLOGICAL EVALUATION OF A MODIFIED TRAVELING SCREEN MYSTIC STATION - UNIT NO. 7 Prepared for BOSTON EDISON COMPANY AUGUST 1981 By STONE & WEBSTER ENGINEERING CORPORATIONSUMMARY On the basis of concerns raised by the U.S. Environmental Protection Agency (EPA), Boston Edison Company has conducted a study to determine the effectiveness of a modified, traveling screen in reducing mortality of fish at Mystic Station - Unit No. 7. Modifications included the attachment of fish lifting buckets to each debris tray on one Unit 7 screen and the installation of a low-pressure spraywash to gently wash fish from the screen into a fish trough. A new transmission on the screen motor allowed the screen to be rotated at test speeds of approximately 3.3, 7.5, 10, and 15 ft/min. Impingement survival studies were conducted on four separate occassions between October 1980 and June 1981; these studies encompassed the fall, winter, and spring seasons and the period of peak fish impingement. The studies were concentrated on obtaining survival data for four species of concern to EPA: winter flounder, rainbow smelt, alewife, and blueback herring. Sampling consisted of collecting and identifying all fish removed from the modified screen and categorizing them as live, dead, or stunned. Live and stunned fish were placed in holding pools and monitored for 96 hours. Overall survival was then calculated by combining initial and latent mortality values. Results indicate that reasonable survival can be achieved among the key test species at Mystic Station by modifying traveling screen design and operation. Survival of winter flounder was high under all operating conditions and exceeded 96 percent during the peak abundance period. Rainbow smelt, alewife, and blueback herring exhibited lower survival rates, ranging from 23 to 67 percent depending on screen rotation speed and species, with the exception of adult herring which showed low survival under all conditions. On the basis of these results, it would appear that a modified traveling screen offers an effective means of alleviating fish mortality at Mystic Station - Unit 7. Further, since the majority of fish impingement occurs over a period of 3 to 4 months, continuous screen operation only during these months should afford a high level of protection on a yearly basis. Finally, on the basis of cost-benefit considerations, it is recommended that the modified screens be operated at intermediate travel speeds on the order of 8 ft/sec.FINAL REPORT BIOLOGICAL EVALUATION OF A MODIFIED TRAVELING SCREEN MYSTIC STATION - UNIT NO. 7 BOSTON EDISON COMPANY INTRODUCTION One of the two traveling water screens at Mystic Station - Unit No. 7 has been modified to permit a test of the effectiveness of the screen, equipped with lift buckets and low-pressure sprays, in reducing fish mortality. On the basis of discussions with the Environmental Protection Agency, four species were selected as being of primary concern at Mystic: winter flounder (Pseudopleuronectes americanus), rainbow smelt (Osmerus mordax), alewife (Alosa pseudoharengus), and blueback herring (Alosa aestivalis). The latter two species are difficult to distinguish from each other; therefore, in this report, they are grouped as Alosa spp. Previous studies at Mystic Station (Stone & Webster, 1978) had shown that flounder are capable of withstanding impingement and removal from the existing, unmodified screens with relatively high survival. It was probable that the modified screen would enhance survival of this species further. Smelt and Alosa spp. had not been evaluated at this site, but available data indicated that adequate survival might be obtained under certain conditions of continuous screen rotation. Therefore, in order to determine the survival of the four species of concern at Mystic, an experimental screen system was installed in the fall of 1980. 1One Unit No. 7 traveling water screen was modified in an effort to enhance fish survival. The existing Unit No. 7 screenwell is shown on Figure I. Modifications included: 1. the attachment of fish lifting buckets to each of the existing debris trays; 2. installation of a low pressure spray header with nozzles to gently wash fish off of the screen after passing over the head shaft; 3. installation of a fish trough to collect fish removed from the screen; 4. incorporation of a fish collection area from which the fish can be gently removed and transferred to holding tanks for latent survival studies; 5. movement of the existing high pressure debris spray header from the ascending to the descending run of the screen; and 6. installation of a new debris trough (located directly under the fish trough) to carry debris around the screen to the existing Unit No. 7 debris trough. These modifications are shown on Figure 2. In addition to these modifications, the screen was equipped with a two-speed motor and a four-speed transmission. The transmission and motor permitted approximate 20 17) 'to 0 0i

77'- 6.. • of S T C R R A E V E E N L I N G WA T ER C.W. PUMPS A 311 `DEBRIS TROUGH PL AN

FLOW DIRECTION A ♦ C.W. PUMP GATE SLOT

TRAVELING WATER SCREEN / STOP LOG SLOT MAX.H.W. EL. 15.78' MEAN H.W. EL 10 45 1 EL-O s -O N mi

EL. I7'- MEAN L.W. EL .0.78 1 EXTREME L.W. EL.-2.72' FLOW DIRECTION

4 EL-7.2 1 CURTAIN WALL BAR RACK r"

-- 1 LC EL-27'- 3 1 ' •

• ." • • BOTTOM SILL SECTION A—A 0 10 20 I t I SCALE -FEET FIGURE 1 CIRCULATING WATER INTAKE MYSTIC STATION - UNIT 7 BOSTON EDISON COMPANY STONE & WEBSTER ENGINEERING CORPORATION-Or SHEET PILING

AQAM I

DEBRIS TROUGH (BELOW FISH TROUGH) G SCREENS i

MMILMWM WIPM . .11, ■ • DEBRIS TROUGH TRASH BASKET DRIVE UNIT LOW PRESSURE SPRAY WASH

CL SCREEN

-0 ■ FLOW " PVC PIPE 11„

ti A. • •

C L #7B SCREEN c_ #7A SCREEN -CONC BLOCK WALL FISH COLLECTION AREA

0 IL

C L #6 SCREEN EL. (

- )7'-0"

• •

CONC BLOCK WALL MAX H.W. EL. 15.78' V

DEBRIS TROUGH

M.H.W. EL. 10.45' EXTREME L.W. EL.( -)2.72'

SCREEN HOUSING FIBERGLASS FISH TROUGH DEBRIS TROUGH EL. 17'-6" - 1 4 7 .T* ;.1 1 1 2U4 HIGH PRESSURE SPRAY WASH

GRATING (TYP)

APPROX HOUSING LOW PRESSURE FISH AREA SPRAY WASH TROUGH FLOW FIGURE 2 MODIFIED TRAVELING WATER SCREEN MYSTIC STATION - UNIT 7 BOSTON EDISON COMPANY STONE & WEBSTER ENGINEERING CORPORATIONscreen travel speeds of 2.5, 3.3, 5, 7.5, 10, 15, and 30 ft/min to be selected. Finally, water supply and return systems were installed in the Unit Nos. 1 and 2 screenhouse to service the fish holding facility located in this area. METHODS The biological evaluation of the modified screen began on October 6, 1980. Two types of sampling were conducted: 1) total impingement collections, and 2) impingement survival testing. Total impingement sampling consisted of counting and identifying all fish collected on both Unit 7 traveling water screens throughout the study period. To accomplish this, the contents of all screen washings for both screens were picked and sorted for fish several times per week. All fish were identified to species and recorded. The primary purpose of this sampling effort was to monitor impingement patterns in order to select periods of fish abundance for impingement survival sampling and thus ensure meaningful sample sizes. Total impingement sampling was suspended on April 27, 1981 due to a unit outage and subsequent shutdown of the circulating water pumps. An abundance of jellyfish, present after the late May restart of the unit and the circulating water pumps, prevented all further total impingement sampling. Impingement survival sampling, which was the primary purpose of the study, was intended to determine survival rates of fish collected by the modified screen. Prior to the start of each test, the traveling screen was rotated for a period of time at the appropriate test speed and all previously impinged debris and fish were removed from the screen and a specially3constructed collection area (Figure 2). Each test began after several screen rotations. As fish were washed from the buckets and screens into the collection area, they were categorized as live, dead, or stunned and were transported in a water-filled bucket to holding pools. The pools were supplied with water on a flow-through basis from a submersible pump located off the southeast corner of the intake building. Testing was primarily concerned with determining the screen speed which would maximize the survival of a species. Since screen speed is directly related to impingement duration and, therefore, stress, it is reasonable to assume that higher speeds would result in lower mortality. However, it is important to clearly define the nature of this speed/mortality relationship, since higher speeds result in increased maintenance and reduced reliability of the screen. While faster rotation may produce higher survival, at some point the incremental increase in survival may be negligible. Therefore, the intent of this study was to determine the optimal screen speed which would yield adequate fish survival while not jeopardizing screen reliability. The method used to determine the optimal screen speed for each species involved a sequential sampling strategy in which two or three speeds were evaluated during each sampling period. Testing in each period lasting no longer than one month. During all test periods, fish were collected at screen speeds of 3.3 and 15 ft/min, which represented the longest and shortest impingement durations tested. During fall testing, an intermediate speed of 7.5 ft/min was tested. During winter testing, an intermediate 4speed of 10 ft/min was tested. In the spring, an intermediate speed was not evaluated. As stated previously, all fish collected from the modified screen were identified, categorized as live, dead, or stunned, and recorded. These numbers were used to calculate initial survival values. All live and stunned fish were held in holding pools for up to 96 hr to determine latent survival. Moribund fish were removed from tanks at time intervals of 1, 24, 48, 72, and 96 hours from time of sampling. All test fish were measured and weighed at time of death or at 96 hours if alive. The overall survival following impingement and removal from the modified screen system was calculated by combining initial and latent mortality values. In addition to recording mortality over time, all fish collected were weighed and measured and their condition recorded to determine whether differences in size or condition affect survival. Examination of length data from past studies indicated that both young-of-the-year and adults of the genus Alosa are abundant at Mystic. Therefore, collection of length data for Alosa spp. also allowed for differentiation of survival by lifestage. In the fall season, samples were collected on 9 days in October and 12 days in November. Winter impingement survival testing was conducted on 6 days in January. Also in January, a continuous 38-hour sample was collected in order to obtain maximum numbers of smelt and flounder. These species were found to be impinged in greater numbers at night. Spring sampling was conducted from April 13 to April 15, and again on April 23 and June 1 and 2. 5Sampling was not conducted at high and low tides to account for possible tidal effects on mortality, as had been planned. The low and variable numbers of fish which occur at Mystic Station, combined with the short sampling durations required in the original sampling plan, would not have yielded sufficient numbers of test organisms to permit comparisons of tidal effects. In retrospect, qualitative observations of proportions of fish initially live, dead, or stunned at high and low tides indicate that tidal differences in impingement survival are probably small compared to differences resulting from varying screen travel speed. Data for comparison of screen speeds were binomial. That is, each organism collected at a particular screen speed was classified as live or dead. These data were collected in a period when other environmental variables, such as water temperature and salinity, did not vary to a great extent. Data of this type can be appropriately analyzed by contingency table or Chi-square analysis. These analyses test the hypothesis that the mortality is the same for each pair of screen speeds being compared. For details on the computational procedure and an example of a Chi-square analysis, see Steel and Torrie (1960, p. 346-351). RESULTS Results contained in this report represent sampling efforts through spring 1981. Table 1 lists numbers of fish impinged by week for all species collected from October 7, 1980 through April 27, 1981. In this time period, a total of 103,384 fish were impinged on both traveling water screens of 6rs0.01 NJ PNO..ON&OT7MCOMM7N701 , MCOMCO7NNN*7 N•4H•••• 0'00HP0.4•40.02700.0',40.0 HN

..... FUH 000.0.MMN *C.1 Mriri UWO 70,MH HH 00H M Ch N N NCAOMDMO0r40 , CIM.ONOHM0 0 Ne•MN 0 ..M...*H H C5 FA Cr CD Cr 0. OD ri r- PA r4 0 CV H r4 W3 ' U I- U 4, CV hl CO M cr 0. W W N O 0 0 .0 N co .4 N ococoovm,--eoN.-Imm.00*m.-IN,Im.....-14 42 a o vr-ocomo* . N...1 N ..4 n ri U I- U 7 rl 7 N 0 0 tu 1/.1 .-1 Cr. M el LAMNMNOHOM*NNONMN•H.M H 0 W 0 MMONNIAM Hr•S H N .0 (0 0 I- U 1.1 ti ri N N z la la .-I LU 0 0 • U W 0 N co aomr*.rw.-oo.movooroma-...-omm p1 er4•••• HI C) C5 Ch r- Cr N Cr M CD O7 r4 N CV LA >

P"

U H U r. r- r4 CJ r4 r4 W W

7 N H 0 ..•-• 0 0 O 0 0.• n • ,... .-. 0 )- 1.11 §

- I 1- cv r- cm c p. 43 e N M PA CD C) LA . CD 71A NI r4 • CV • r4 CV • r4 H H 0 Cr) Z Z 0 d-oom...o.or 430- .-1.-1.-1 cosi

r < >1-0 mro,-1 m N 0 w N

j I-11 Z 0

.4 M w HE C13 < Z 0 IL 0 ›...... 0 H rti 1•4 N 0743.0.0.-lo.4o.-om,-4*.clo..oHer4m N ro o 1-1 0 d'r.INNII-17M 0N . 4 Nr4r4 .-1 0 1.4 0 > > 1-. > VI 0. CU hl 0 I MI Z 0 14 0 I- I CC Z Z W D 0 iu Is .. Z U) Z vi r-I Is 0 0 5

' 4 r4 ri 0) OD CD 4D r- 43 o . M CD M . CA PI N PI • • pl r4 r4 CJ CJ r4 r4 rf 05 .. H H. 1-4 a c) cr. r- 111 CJ r4 N CS .0 Cr H N N M 0 ....<

›H> M0..1* O 0 Z Z

0.

H rel ri ,I

pi 6 *. I - L11 iii z w d 2E I - z r 0 0 0 CD CC H W1_ ri CD r4 C4 Ch 45 r4 r- . .O IA r4 . r- ro ••0 . NO • • M CV ri ri M O 00NNHNCO OMN N M '45 1- )1 1300 ›1-..›. 4-m..0 m o co ..- ,,, 0 0 0 Cu 7 Z z

o I.J. :71 E- 00 ti

CO IA N 0.000NNMNO•421Ar4MN.NeMO•••NO.M 0 5.- " 0 00.05Mr4 0 0 H H H H M Z HH> MO0 m cr cu

. 0 o m 1- o Z CZ CD r4 rw N N M C5 CV Cr Cr • Ch r4 Ch N • r4 4, • • N 0 • .0 • • • • . ■ 4 41 - d . 0 o m,-.1,1 M N M 0 Z HHH NN* •••• v 1-# U U r-I CI. 0 0 = i-i 7 0 In r4 N Ch ..40 4) • • • 0 • ri LA •

- 1 • ••0 PA H 0 IX 0 0 .0 r

- I W 1

- 1

- 1

- NM N CO U 0 0 0 Z N M H NHODN • .0 .0N N 45 0 C5HN IV N 5-5-H HMN H U U H O 0 ›. Y 0 4 9 x - u 0. U x In . 0 4 u w X

O 0 0 4 o..1 U -I + w W LLI ILI 03 0 4

0 .-J 0 0 I-i w W 0 Z X Z 1-4 X = Z U .J IX la

+ IX U 0 W V) 0 0-1 4 w X o U 1--wuo o -1 rex > wm w 4-- z E . ww0= ,.... .4 . .0 01.- . u ,.z_z _, .. .- , .4 2m0... 00 m 000 p.. W.a.D00 WW =XmWWW F-1 HW 4CJW 4 1

- 1 ZOO 0..J ZWOHJ Wa-= U<CWZXZWEA MO NU ZWHW 1C40 W CAJJ .... HO {XXX< Z 0 WU.= CAZDO ZCO W <ILO ZMH W UZUUCCUOZZ ZMH MOO=D U Z2 0 =..w HZZ<CALL M04 MMO.M2MCC 4 HO Y.A.MOCAOH HD WZ 0 MHHUUICCM W..MHHZHUWWOU"'ZW MCA H WH MO MO CO<WZMOMWWWWH WZZOZMZ=OHOWM 01Z>.LLWMZ CO U.-W ZCAH<JJWHZHHO>4404=HHHM.JOHMXM 0 4ZO-HM<XWX W"

- "" HOZ-IDJWMHZHODJJJZJ MMDW-JHMDUDWH ‹M-JOZU maqr 4 X_IH)

- .(30=MD=M=MHH)--5

- 00.:(=WZHUHOU0-5XHHMHO MUZ M43<COM<CHC0UX000‹<Z<ZZZH‹)-D00=LI-OCAJOOCEUZM

0 0 N ow.TOTALS BY WEEKCD MI CO MI C4 -J NP r4 U10 I.- 4) 04 • CD r- 0IAM r4 PI CP 0 LI 4) • tu • gr • CO CO LO CP • • • CV r4 r4 r4 • r4 4 4) CN PIA PI pn r- 40 NM r4 r4 IA P O Cc r- OD gr r- 42 r4 PI CIJ r4 N 41 C) CD CP MI C4 r4

• F- it r4 P. NI N N PPP c) cr Ch C% MI • W4 r4 • • • r4 •r4 • • PI r4 C) CD 144 CP rI r4.C4 IA CC V- IX N N IA CD 4) N r4 r4 Ch CP 0) 4) UI CN r4 • Ch r4 • • r4 • • • 5.4 rl 42 0

O .0 r4 0' r4 CO r4 ' 0 4) IX P. IX 4' 4 4 4-4 z z MN CN Ch CD 0) 42 Pi a) 4) m • Ch um re) 0 o ch 4-4 rri /-I N MI r4 IX I... CY 1.1 1.1

N CO CO 4 4 P Z = r4 Cr N MI N 0 r- .14 pm 4) Cu pl r4 • 04 r- 0 PI • • cv ct N 0 r4 M /-1 4' 11') r4 C. CO 1-• IX MI PI rX LU 4 (-3 U. = IX 4 = r- pn N N r... tu .0 Ch CP MI CP V. • r4 U) r4 • • • • MI N

0 o 1.1 r•I V rl .-1 N /-I 0 01 I-• OD V) ri .4) ILI LU 0 U. U. oa C% ri CD 4) Pi r4 r- N NI M r- P•4) 04 • N N N • • r4 • 0 r- r4 ,-1 • • • ,-; 0 + 0 •4) a) 41 .0 d• r - et IA o o a 1 4 - c0 o• m r+ pn LU LU N VI U . U. M rk us PI 2 m C. C4 PI N Is cp in 0 rr • r- CP CP • • 0, • r4 ri r• LI. LU C) P. PO pn N r- N N Ui 4-4 4-4 4-4 O 0 to I- m in o• ev .

- s cu * LU UJ ILI l's CP

Cu 0 II. U.

I. I 14 Is N UJ P ■ N 02 cr 111 r- r4 Ln in mp ..411 4. 4 • • • • 0) 0) r4 cr CP = C2 rs in gr 0 c) r- ri 04 ,-4 pn O I- Z I- CO 0 Is- .-1 .-1 N ... 1.-1 4 W N 6-1 .7 -) U.

r4 UJ Z CD 42 .../ C) N N N CD U1 CP CP r4 P. r4 • N 00 • C4 • r4 4) P. pn r4 • • ri rl .c• CO I-I 0 0 m r• CO C. I , r4 V) CP N 4

I -

- Z ~ 4 n p

7 n v q - a 4- -) --) 0 C) NI Ch

H r4 r4 r. NI p4 In C4 42 N CD • Ul C. V, • • N 0 r4 N • • • r4 NN • • • • r4 • • • • r4 I- 0 a• PI 41 .0 In Pn .-1 c) N ••• ■ ri N c‘ gA Z I- Z cv .-8 v r- o• IA F-1 et

>- 4 4 n * cr

x -) -) r4

F4 43 N , 4 PI CN r4 gr r- Ln pn r4 • N CO r- r4 04 C4 Ln MO • 1.4 PI .4 • • 0) 0 0 0 r4 Ch cr P. Ln r4 4) r4 r4 CP N PI CD IL 2: I- 2: pl ri CP CJ r- r4 PI O 4 4 N r4 r4 .0 Z " 4 ) '1 /-1 rl H E CD 14 H NI V, r4 MP N C. NM • 143 r4 N 4P CN N CN r4 pn • r4 • r4 • • • r4 r4 • • • N C) Is 0 0 0 111 r4 131 N0 UZ N W 4:( N UJ O -) • .• ). X CO 1..) CO 4 D Y .-. CO M I.) X 0 Lu •::( LI ILI D 0 CO 01 4 H U J + La W111 W CO La 4 o 0 I-1 LU LU 0 ▪ Z Y Z H XZ Z U ..I O. LI + IX U 0 LLI 0 NH 4 W X 0 ix o o H Z 0 /X Pi CO ...: 0. U IL1 W 0 X I-. /-I 4 W IL. o 0(- 144 Z U r U. 0 U 0 0 .J IXM > WM 0 ILJ r. 2 = rI .4 L-I Z 7. Z -1 LuLLJ cEZ _4 0.4 Z=0.4 041 01 0010 ILuZDOO wit) X X CY LU ILI Lai H 1-1 ILJ 4 U U.1 -J 4 I-1 Z 0 0 0 J =al./W--1 ILIZX u a 4L, x x .1

- . ILI 0 0.U1 0 re 4-4 m x LLI I- Li. x <c u IL,

0 ..I -3 .... I-1 VI IX S X <1 Z CO La u. :7_ in z m o z: co ii, z cc 44- 0 z D- 1-4 W U = (.3 0 .:C tl 0 Z Z Z o. i-o P.002D (.4 ZZ

0 3 •• #.1 X X .% Cn Lio Ci. 0 .% 1°4 1.1 n_ 4-4 x cr cr 4 V. 0 ). CL CL 0 1l) ..... 0 Pi Pg D UJ ",' C2 M F- 0.4 (3 c, I LC Cr UJ 2: CC V. V. X V. CJ ui Lu CD c) 2C 2f 4) cc 0 I-4 W I- 0.0 HO CO 4% 44 2: 0. C) Pi UJ LU ILI Ill F- UJ 2: 2: 0 z o-i = DC C) ri CD Ul 0. Z>W 0. 0 C.1 :I: UJ :: VI V- 4I -J -.I IX UJ P- 2: P- P- al ›. a 62 0 4Z IT V- V- V- IX -.4 CI r4 0. nC IX a 2: 0_ I- ri 4 IC LU nc UJ 2.: 2: V4 0 z -J :) -J LU Ce i-- z 1.4 C) :), -J -J -J 2: .J :: fX CC :D LLI .J V1 IX 707 Lu V4 Z 4/ CC -J 41 z L4 0. CD .1 .2 ..) 1.4 1 -.. LI C) :: :: :2 D = o. 2c ri r- I-- r4 r- D 0 ca cc :: Lu z c) p. C) L) sp. D 2C P- p- = HO 01 LI :: IX 4 3 4 41 o. 4 F- ID C.) 2C CI L) 0 a 4 3 4 = 2: 2: I- 4 )- D 0 cri m: U. ca Loa -J CI 40 4 L) 2: MTOTALS BY WEEKr.r4C4 CNCNCNP•OW•DNr-40,0r4A0MOC.MAMWMC. , ONO.‘0140000MNMM W4 MCNr.N00000.C$P4M0M.-1.-10047.0 F.Z6- 0.1.0.0 7wme.oammor ...... upo * vMommm OnF• N

0 0 0 Or4O N ..JWMPOMNr4.0.N.D...m.m.0..w W< NW-.MCNMMPI M N 17. C ,. I-- cn cl 04 r4 <70 M =n1.

C4 r4 • m N ow .tr 5 O 111 r4 C4 0

M < N N r4 O 0 >• )- < < 0 e4

• IA rl • -• . )- cv . a r . S. S cr co LL S NO O cr I m . N .4 W M N N wm0Npmeme. •VM • • . 14 •V •N V = .7: 0 45 M C4 Cr r4 .4 a in o D M P. CC .4 .4 a m C.

• 2.t 4i CC .4 CD r4 W F. < J

a P4 c

0 , IA 42 r4 CD C4 cri CP, CD 0 CN .4 • • • r4 • a •O • • C4 lit 0 I- CD an r- 04 a Cr PI r4 r4 CJ PI 42 cn CC F... CC Cr ,.4 M Ch F• C M U < 4 .4 V 1.0 n m n ,... 0. 0 Nmar4m04 .0 • • • ..- 4 •V .4' .4 M 4.. 0 v +4 .4.4u .4 N

1- MN= IA N 0 M M 4 4 4 0 w +4 V

O M cv.org .mmvfti•V 0..v +41• 0 O v 0 ., cv 14 mI-m N .4 ..I N . M & < M ;to In Cr CD CC C4 PI ON C4 .4, CP PI CD r4 m • m CJ VI • m • .4 VI W 0 COMM MMM itt

CO MI- M M M = S S R... .r. - ). Y m u W a , x m . .4 „ . x = M In < M U ...1 i W W W W W U 4

M .J 0 u .4 w w al X X X 14= X = U -I M w + M U 01.. No .4 4 w X tn moo m no mm m m u wwo= r- ma wu -1 . o oi.- m = u o-.1,.0uo 0 J. m= >w m o w I- =7. m ..11.44- Z ..1 WW CC= -JC. < .'.'0..J 040 400010 n w-=5o ww -.-xmwww mm w cUw_, a p-i- , .mo 0.-; =c1501-..J wz= Oawx==wom o ommn =w l-cA.'±

- au w m_J_, - mo m-=a o wu.n o- norm w all.c, -mm w u=uuZu- , -o= =p.m 1

- -1-•.005 u zE N =.- p-izz:imu. mem< .....ic i „..; < 4- 0 )

- m vi mo .... 0m ,-, w= o mo,luolfsm w-mp-1-:.1,Juwou , -.mw mm,-, u.11.- mo O mawzmomwwwwo- w-zon= , -f=omowm oiw=>-wmz o ur_w =m)--,.J.Juwr-zr-m>aaga m.jommxmmezr-marw= w- P40.

- -JWMF• r407-J-JJ-Jet=M7 DU WM<M-JMZU COQ c_Jgruo-_-_-m:cmio.noa

- w

- Pu.-4o5ums.--p-mmo

cn ci = m a :: as o a. Z: r- m U = M kJ 0 .1 CZ :: 4 2 :: .. 1: F- ;i )- 5 in vi = U. - J 0 0 40 VI <2 U 2: mTOTALSBYDATEUnit No. 7. Smelt were the most abundant species collected (45 percent), followed by Alosa spp. (alewives and blueback herring, 20 percent) and winter flounder (19 percent). It is important to note that 75 percent of the smelt impinged in this 29-week period were collected in 5 weeks. Likewise, nearly one-half of the Alosa were collected during the week of November 11 to November 17, and nearly 60 percent of the winter flounder were collected in January. Results of fall and winter impingement survival testing are presented in Tables 2 and 3. Initial mortality is the percent of the total fish that were dead when collected from the modified screen. Latent mortality is the percent of the live organisms that were placed in holding pools and then died within 96 hours. Results are presented by screen speed for each species. Since space was available in the holding facility, many species which were collected in low abundance and were not specifically part of the study were also tested. Some of these less abundant species were not collected at all speeds, and it was not practical to extend sampling to attempt to do so. Thus, results for these species are qualitative only. Results for Alosa in fall testing were partitioned into two length groups when a plot of number tested versus length revealed a distinct bimodal pattern separated at 10.5 cm (see Fig. 3). Data from Scott and Crossman (1953, pg. 103) indicate the fish in the first mode are in their first year of life. In Table 2, these first year Alosa are listed as "Alosa (alewife and blueback) small." Small Alosa were captured in abundance only at screen speeds of 15 and 7.5 ft/min, despite numerous samples collected at 3.3 ft/min. These small Alosa survived impingement well, especially at the 7J •-• <X /-• > Z 1•4 LIJ > I- ■ IX CC 7J CO cD hn I , cp. cp. 0 ca CD cD CD CD r4 CD CD r4 NI CD hi C) CD EC) hi CD MI CD r- Os CD r. CD CD ati 0 C) CD CD C3 CD hi CD rcr) r - cz U1•0 MO en Co 0 0 cn r-1 PI 0 ED r- 4::• 0 r•• ■ 007 hi o hi c• v• N 0.00 fs LC) 00000C/KI0.0 X • • • • • • • • • • • • • • . • • • • . • • CO N

i• • . • • • • • • • • • • • • • . • • • • • N4 CD CD CD ED hi 0 • CD CD CD CD r- 43 rl Ul r- Ul'gr C5 hi CD 0 CO I CD hi CD 42 gr cD E0 CD hi hi Cr CD CD CD CD CD hi CD ED ....1 061 Cr C7 CD OD in Ch OD LII OD OD CD hi 0 hi pi 00 0. r4 U1•0 C) CD CD PI r4 ..J <1 r4 r4 r4 r4 r4 ...1 F4 <X I... Le I-I LU Z > I-I 0-. N -.I <X 5- 0 _s 0 (0 CD CD CD CD CD C5 r4 CD CD r4 CO CD CD C) CD 0 hi CD hi CD CD Ch. N C r D ED D un D D 5 C C C D rI- : hD No n g ED DCDD un .

- 4 M OO r4CDCCC1ChD0 0.00 In r- hi CD CD CD CD CD CD CD ND X FA • • • • • • • • • • . • • • • . • . • • • • • • • • • • • • • • • • • • • • • • • . • • • • UJ > CD CD CD OJ U1 a) • cD C3 C3 C3 P. 4D Ca U10 Ul Ca CD CD CD C3 C5 PI CO hi CD CD Cr C) ED CD Ln rn 7 CD C3 CD CD CD CD CD ED

I--C r4 N7 CD CD 0 Ul CN OD ED OD CT CD U3 cD 41 hi 000 r4 111 .0 000 1(5 r4 EX M .-1 r.1 .-I r-I .-1 rd r-I r4 r-1 -.I U1 CI LU O O r-• 0- rs o • -4 in • • ri CO NI sO CO hi PI • •-1 • ri rl • • • .0 • r4 rsi NJ • rs d• • • • •- 1 IX N r-I r4 CO Cr I LU r4 r4 r4 r4 Ul ED OD Ch 7: 2: 1.1.1

>- rCC

› FA 10 :D . C3_

J r4 • ri r4 0 OD • • • .4 r- r- hi gr gr N 0D a) r4 r4 r4 • In N • 111 r4 N • r4 • r4 N • • r4 r4 N N r4 .4 . .r4 • r4 ° 0 )- I (X LU 111 Os 4

ri csi hi r4 F-1 pi hi

I- 40 ca (n

ZZ 0. - < M 0 z z ...1 H •-.1 2 < Z 0 x N > -J N 1w D U s-• -J <X Ca O. CD hi hi 05 CD c) 0 CD CD CD CD CD CD CD 0 C) CD r- CD ON 0 CD CD (7 r- 0 o CM CD CD CD CD r- Ul 0 0 0 CD CD r- r- co CD Q > r- r- pi hi 0. r- CD 0 CD CD CD CD CD CD CD CD CD hi CD ED CD CD CN CD CD ca 0 cp. 0 c) CD CD CD CD CD ED un co CD CD CD CD ED E0 CD CD

-I > I Z I-> hi gr r- pi r4 (0 CD ca CD CD CD CD CD CD CD ED CD r4 CD ED CD (7 4D CA 0 0 0 ED CD CD CD CD CD CD CD ED ED hi CD CD CD 0 40 ED CD CD

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . LU ....1 CC J 'I D Cl 2: :3 HOC OD 0 0 ul ch 0. CD CD CD CD CD CD CD CD CN CD Ch CD E7 CD CD N 0 CD CD CD Cr , CD 000 ED Ch ch 0 ca 0 ca 4D ..0 CD CD r4 ei r4 r4 r4 r4 r4 r4 r4 ri ri ri r4 r4 r4 ri rl r4 r-I ri ri r4 r4 ri r4 r4 U. Z M M F-1 V) I

- I

< U- 0 l'- 0I-I 13 'n z i- I- LU i- < -I LU 0

n 2 0 (/) w Lu Ce I

- -,. ° U U) e- -' 0 F1 F. co CL 2 0

LIJ ...-

,_ .-1 F-I 1-I .J I-- ce 00.0 r4 CJ

03 zr Ln ao c. r4 • r4 1/1r r- 0 NI ED CD .zr r4 0.1 r4 NJ r4 r4 CD ED r4 ED r4 Ca • r- • NJ hi NJ • :9 2 . 4 4? NI r4 r4 r4 CJ Ca r4 NO

F4 .70.10'0.10.14' ri KI I-I LU pi s-I r-I M CM .4' Z 1:13 1-1 De: M Z CI PI Ul CD hi Ul CD hi 141 CD hi in CD NI Ln C3 NI UI CD MI un CD hi 113 CD U3 hi Ln CD un U3 CD hi in U3 CD hi Ul CD Ul hi CD Ln rn in 0 Ul LU . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . • • . . • • . . . • . . • . . LID PI r- 111 hi r- ul hi r- Ul hi r - un pn r- un in r - in yn r - un rn r - in r - rn r- un r- r- 41 pn r- r - un in r - un r - hi Ul Os hi r - Ln r , CC r4 ri r4 r4 r4 r4 r4 r4 r4 •-1 r4 r4 r4 r4 41 OS OS .s. AS OS 0S - J -J ...J -J .J -J ..1 -J -J -J -J -J cX cX cX <X <X <X D.: D: D: M= D: 2: NN V) 41 NN .., IXXX X X X CO <X CI EC cX EX cX n x x 030011:0010 ce U C. , W UJ LU LU LU LL1 (0 G¢ :3 :3 :3 :3 :D :3 03 03 ..../ -J -J -1 _J -. W+ IL LIJ COC000030703 u ...t X

-J Z X Z Z X + + + + +

- r 4.1 In 4 Ix 0 0 I-1 0 C.) IYCCI:trECKCY 0 I-I -I 0 = ...- -'" CO FA 1-1 O0 CD UJ LU LU III UJ IAJ UJ CU U.1 13.1 LU UJ <X U. = I-I I-1 0 I- 3- 0 0 0 LL. LL. U. U. U. U. 0 CD C) en en CI -J -J -J DC b.1 0 (D rt £ F... F

. - I- IX 0 cn (J CD L) FA 1-1 FA F4 FA T4 Z Z 2: 1= Z 2:: wuJuJZ EL Z • .

- 4 CC Et -J ....I -J <X

= 3 -'" -,- xx nmDnDmwwwccecr UJ 4-1 <COLULLJUJUJUJI.LILULU 566 X LU LEI in ro IL.1 14 DC 7C MC CD C) (D CD CD C) X X DC U.1 UJ 11.1 = 0. 41 -J X 7: ---: .' 0 2: 2: I-- I-- P.- U ..i -J -.I .J _J -J 01 01 0) _J -I _1 _J __I J LZXXXX CD CD 0 r in i -4 - D:

<1X<XC ri-- UUU.U6U.CXDIuLD0CC2 :DL 2: C. CI. 000 iLl

tr, ......, U. U. L.L. <X <X <I FE 7: x x Ce DC X <X 2: FA I-1 3 :C ::: (X On on F4 F4 F4 CL LU CC IX M CC IX ce ce ce M ce Ee ce Ce M ce :: .7: :: I

- - CD CD CD La u U U 1-1 I- I- 0 C) C) it.' I 1 CD F- I-- hI-4 CC <X <X cX .1 EC LU UJ UJ ILI Lu UI UJ UJ LL1 LU LU LU UJ LLI 'Li Z Fc FA T4 DC 0 0 Fq 0. Z Z a) 0 0= UJ U.I CD Z Z Z LL1 CD LU 01 01 ti Ul 410 F- I- I- 2: 2: 2: F- 1-- F- 1.- F- I-- :). :D. :), OD n3 ca <X :: :: 7: I- _J _J CZ -J EC <X 2: 2: 2: F- UJ Up F- <X <X <X FLU DC 0 CD 0 CD CD C) F- I- F- 2: : 2: 2: 2: 2: 2: 2: 2: _J -1 -J M :7 :7 -.1 X is 2C M -J _ J LU :7 -I -.I 1-4 F4 FA M M CC :3 _ J ..1 _ J Fp D. <X -J -.I -J _J -J -.I M :D :3 M :D M FA FA FA FA Fi F4 F4 F4 FA X 3: 2: F - :3 :D :3 0 CD CD :: L) F- F- <X <X <X C3 DC DC <4 I- F- I-- 2: 02: <1 <X <X <X <4 <X 03 c41 ci3 CD CD L) X X X 2: 3t 2t 0 0 0 U () CD <X :: 2: ;: 2: CL CL <X 0 <X <X CY CY ce 2: I- 1-- 1-- <X <X <I X

O EX ...J 0

UJ • CC 1-I •-1 PI 7 Is CO Cal I- IX CV PI NI NI Ul LLI Z CO 1-1 z

r4 • Cr • .4 • • hi • • • • r4 r4 • r4 • • • r4 Ch r4 hi • • • • r4 r4 • •J • 44 1-• > Z F4 141 > IS J CD CD MI r ■ CD C4 C) CD Ch CD CD 07 CA CD 0 C) CD CD r - Ul c) rn NI Cr r - CD CD a• CD r ■ CD 01 CD 42 NI N CD VD C3 CD N 0 42 Ch OD CD CD CD CD CD Ch N CD VI al N .4) CD CD 4) CD V) CD 30 • . • a • . 0 • • 0 • . • • • . . • • . • • . • . . . . • • . • •

D4 C> CD Pa v3 CD 0 LA CD 41 CD CD r - CD CD CD CD CI CD CD r4 CD 04 02 VD ND al CD V3 In ,-.1 0 .-1 PI Ch CD Ca CU r4 OJ 0 CD CD CD r4 NI Cr N La VD ND r ■ CD OD r - ch. - J <X •-4 r4 •-1 •-I r4 ‘ -1 1-1 CC Fa' F4 LLI 2: 2> F4 C) .. .J

• C) CD CD CP CD CD C) CD CA CD CD r - CD CD CD CD CD CD VD VD r4 CD NI Cr 0 CD CD F- C3 r - CD F•• 2> CD CD 0 la C) MOO N 0 42 La CD CD CD CD CD CD al 44 CN r - rn N C> 0 CD VD CD 40 CD Z F•1 • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • • 11.1 2> CD CD ON CD ON Un CD Un CD C2 a) CD CD CD CD CD r4 C4 CD NI 0 OD CD CD CD v) Ul r4 CD 1- C IIi CN OP N r4 Cs1 C) CD C> CI r4 NI Cr 44 V) CD CD CD OD r - ch < r4 r4 r4 r4 r4 r4 r4 r4 .J Ul 0 4C EX 41.1 :3CI C3 Ch Cr r4 NI • r4 NI NI VD CD 40 CD • • • • r4 NI Cr r4 a) 44 la Cr • • • 44 44 r4 al • 2: EC r4 r4 MI al N NM N La 1 aJ .0 Ca LU > I= 1-4

r • - ..J >-* CD • • r4 Ca la al r4 • 1.1 • • al OD VD a/ r4 • • N o 4 - r4 In VD C4 N al rn 4) r4 • • ca . x Et . u, r-1 r4 •-1 .-1 el Ill .1 - NI rl r-1 F-I V1 Ca

LU r4 .4 r4 r1 0 ›- ) Ch i 0 1-'. Z Z

CD < z I - OH I- -I " ce) <

` J O Z 0 ...J a ea CD N r4 CD r4 CD CD 0 CD CD 04 Ch CD 0 CD CD 0 al OD 0 in CD r4 N CD CD CD CD 0 CD C> 1- ... s > D U a> 00 VD CD CD la 42 0 CD CD 0 Ch C) /7 0 CD CD CD Cr 0 N CD CD 0 VD (2 CD CD CD CD CD CD rn pg p-1 • . • • • • • • • • • 8 • • • . • • • • • • . • • • • • • • . • EC > 1- 2> CD (7 VD Ch CD Ch CD 42 CD CD C) P ■ 0 0 CD 0 CD CJ CD N v) N IA CD N v3 In CD CD 0 CD CD C5 W 1 Z F4 IX CD 0 V) Ch 0 Ch 0000 CD 0. OD CD 0 C2 CD C> Ch CA Ch Ca 00. .4, N 47 CD C) 0 CD CI W I- Cr 0

z n .

- 4 r4 r-I r4 11-1 r-1 r4 .-1 .-1 ...I Fl 0 ... I z 1-4 Z V) MX U3 0 1-1 0

,_ u. , 1-1 13 a 1 - 0 1- 1.- w ...1 LU Z cx

a co I

- 1 • • r4 r4 • I-1 r4 .-4

V/ CP r4 NI Ch • v) r4 r4 F.-. IX 1-1 LL1

1 0) 0 Z 01

0 .... IHi ILi Z L9 ;2, 2 .-. 1-- in W il U) M .J <X ..1

1.4 M >._ Fy 0. 7O.i..0 r4 .7 crpnch r4 CO r ■ OD P ■ V) 1-1 r4 VI ri r4 allaCD 40441140 VI 0 IA la r4 E 1.•• 4X N CI C r-1 •-4 0" •-I rl in r4 rn ...I ry ,4 1 .. - v 0 .0 r4 .

- 1 1.4 ILI .4 NI r4 Z al )-4 - 5 .- ED la C) CD NI CD CD al CD CD NI CD CD NI CY CD CD NI la NI CD CD NI CD CD NI NI CD rn CD CD NI 42 IL . • . . . . . . • • • . • . • • . . . . . . . . . . . . . . . • MI NI CD la NI C) In In CD La NI CD Ill NI C) in ul hn al MO la NI CD Lfl NI NI La NI CD al NI al 13. r4 r4 r4 r4 r4 .4 r4 r4 r4 r4 r4 r4 r4 r4 r4 r4 r4 ri r4 01 • A, I., A, .J -J .J -J -J -J CC CC *X 2: 2: al 0 al F. >-. 0) La

>.- X X X 03 LI LI (-1 En a) al <X <C < D D :3 X X 03 c0 al Ex Et IX as

Li LU DJ LU CD CD CD <4 cc :J :D :D EOM .J -J -J +++ al ILI IL1 03 CO LLI 0 Z Z '''' 1-1 x x +++ Et cr te o 01 0 LD EY Ee re 000 2 IX F4 Fl CI 0 0 LU Ill LU IL1 LL1 LU I- 1- C) CI CD

F4 1-1 1-1 2: 2: 2: ii,T.D Ej (T, LT ! 1 ;. ' ,.- F- 1- ■ F- I- 1- 01 Cf1 L) 4.) Li 0 a- 0 CD 0 0 2: 2- .,.. LC LO -J -1 -J -1 -J ...I -J ILI 2: :: 2: :1 :3 :3 CD CO CD LU </ FA LU al W Lu LU IJJ X 0 iii 0 Z3 5 0:

W LU 0 000 ■

- • ■ , X eiri VI Cn ul OD u) u) 0 . 2 r: t.; 1F

- i I-- I-- 1.- L.) bi .J

- J .J .J .J _J Et 2: 4 .4 cc u_ cc. u- v v 0 fl LL CI CI L) LU et 01 ... V V X X X X X Df 2: 2: 2: 1.4 5... F4 22 3: 2: 22 :‹ 2C 0 0 0 ri F4 F4 EL CL LII IX CC CX 0 4.) LJ LI 0 0 1-4 1-4 I

- 4 1... CC P.- C3 CI CD CD CI CJ ILI I I I.- I.- F - 2 1

- 1 <X <X <4 W LU Ill 0 CD CD CD CD CD a. a ra. :X CD 2: CO C3 cn 0 03 CO F- CU LU 2: 2: 2: aJ CD LI W (n v . ) ol I-- F- F- -J .J ...1 -J -1 ..J -J -J -J cZ X CZ 2: 2: 2: -' 2: 2: 1- LU LU CC CC e2 I- ca ici :: CD CD CD 2: 2: 2: ...I -1 -J -1 -J -J :D :3 :J -J LD .J 1-1 F4 1-4 g 1-1 1-4 0 LX CC -J -J -1 F4 2: ct. 0 _J ...) _., rq 'pi hi C) CJ 0 CD C) CD Li L) 0 F- F4 F- , CC .2 4 , I .:( *1 la. x mc h - r - r - 27 1-1 NZ cC <X 0 X X X EL EL EL EL a. CL 0 CD LO c: MC , 4 cc ce cx re Ex Et cn r- r- <X 4% .1 :fp: XN z O

In 0 0 ri Z LU M

CJ

* * * * * * O * * * * * * * * *

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * >l< * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * Z Z * * * * < * * * * U) * * * * * * * * _I * * * * 1-0 * * * * * * * * I-I Z

tat Z 0 cx > * D l) X HI * 0 *

M > * ce IX I Z * UJ < •CC 0 tz 0 en D Z (f) (/) CD ...1 >•• 0 , * H •:( 0 * *

. Z 1.... " lL C 3 * LIJ Z l'' ILI D < a ILI lil Z * * R' E * * U_ U) 0 * * W I- * * L9 0 (11 * * Z 1-1 0 1-1 I- CO * * fl U) E * * IH >- * * * * * * * * O * r

- I * *

* * * * * * * * * * * * * * * * * * * >lc * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * ** * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * /IK * * * * * * * * * * * * * * * + + +--- +--- + + +--- +--- + V Z o o o o o o o o o LLI N ty ,-.1 co co cv cr. vo rq H m cv cv cv ,--1 .-1 er lLl

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * >- 1- p CV CO15 ft/min screen speed. Results of tests at 15 ft/min show nearly 50 percent survival (initial and latent combined) 96 hours after impingement. In general, impingement survival increased with screen travel speed. The large Alosa showed high initial survival, but latent survival was low at all screen speeds. Results of fall testing with winter flounder are also separated by size since a plot of number tested versus length revealed a bimodal pattern separated at 11.5 cm (see Fig. 4). Data from Scott and Crossman (1953, pg. 281) indicate the smaller fish are in their first year of life. In Table 2, these first year winter flounder are listed as "winter flounder small." From Table 2, we see that over 50 percent of both large and small flounder survived impingement even at the 3.3 ft/min screen travel speed. Results for fall testing with smelt are only marginally quantitative. Smelt were not greatly abundant in the fall period and were impinged less frequently during the day (when impingement survival testing was conducted) than during night hours. Results indicate about 3 to 4 percent of the smelt impinged at this season survive. Results for other species are qualitative since test organisms were few in number. However, in general, it appears mummichogs and cunner have good survival potential in the fall, while butterfish, mackerel, pollock, and white perch appear to have a poorer survival potential. Results of winter testing are presented in Table 3. During this period, only 16 Alosa were captured due to their low abundance at this time. Data 8* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * >X * * * * * * * * * * * * * * * * * * * * * * * * *

1-i * * * * * * * * * * * * * * * * * * * * * *

* * * >X * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * >X

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * (..) + ...... ...— ..—.. ..... + e ■ ... . ■ 4.... ... ■ + ■ .. ■ ... ■ .. ■ + ... ■ ■ ... ..... ■ .. + — — — . — z IV 0 IO 0 LO 0 M N N .-I r-I 0 Ill CY U-

* *

* * * to * * * N * * * * * * * * O * * * * * * * 0. * * * * N * * * N * * * N * * * * * N * * * * * N * * * * * * N * * * * N * * * * * * * * * >X N

N * * * * * * * * * * * * * * Cs1 * * * * C.J * * * * * r-I * * * * * N O * * * * * 0

O. 0 * * * * * N * * * * * * * P-1 z * * * * CO ILI * * * * * * * * * * N * * * * * * * * * * * * * * * * * * * In * * * * * * * * * * * * * * >X * * * * * * * * * * * * * N * >x * rI * * * * * r4 * * >X * * r-I * * * * * O * * * * r-1 * * * * * * * * * * * * * cO * * * * * * * * * N * * * * * * * * * * * * * * + — — . — .-- Inindicate Alosa survivorship was no better than that for large Alosa collected during fall testing. Flounder tested during winter showed very high survival at all screen travel speeds, as shown in Table 3. Results for smelt are separated by size since a plot of number tested versus length revealed a bimodal pattern separated at 14 cm (see Fig. 5). Data from Scott and Crossman (1953, pg. 138) and Liem and Scott (1966, pg. 121) indicate that smaller smelt comprising the 9 cm to 14 cm mode were too large to be first year fish. Therefore, it seems more probable that the two modes represented, respectively, age II fish and age III fish. Initial survival for large and small smelt was high for all speeds tested. Latent survival was significantly lower at the 3.3 ft/min speed than at the 10 or 15 ft/min screen speed for both the large and small smelt. The 15.0 ft/min screen speed yielded the greatest survival for both the large and small smelt, however, it was not significantly different than the 10 ft/min speed. Interestingly, the smaller size smelt had greater survival than the larger test specimens at a given speed. Results for other species tested in the winter are more qualitative. Sculpin survival was very high as was that of Atlantic tomcod and threespined stickleback. Pollock of all sizes appear to have better survival in the winter season at a screen speed of 15 ft/min than in fall. The few white perch collected all died. 9rl Pel

r") Cs.1 CS1 rl Cs.1 * * * * * * * * * * * * * * O * * * * * * * * * * * * * * *

* * * * * * * * * * * * * * * * * * * * * * * CP. * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * >- 1‘. * * * * * * * * * * * * * * * CI * * * * * * * * * * * * * D • * * * * * x< * * * * * * * * * * * * * * * * * * * * ,,, Z Z ,,, < Jr

~ ,

f L * * * * * * * * ' E * * * * * * * *

CX * * * * * * * * Q > Z 0 —, 0 * * * * * * * * X I•4 ."" * * * * * * * * 4...)

in > ce cr I Z * * * * 0 ILI 1.• 'CC * * * * M ILI w o * * * * 0 = )•• 0 ).", * * * * I-1 CI) U I/ Z 1••• " ILI 1- iii * * m 4. . i . * * CY (LI -"`• * * * U)

LU i' Z * * * V' IA * * * Ir L9 U (A * * * * * * * * * * * 1 . 4 0 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * X I-1 m - * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * r-I * *

* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * )I( * * * * * * * * * * * * * * * )1. ..-. ..-. ... + ....- +_--. 4. ..,-.. .... ..... 4. -.. .--.. .-.. + ..... .-... 4. U Z C:) 0 0 to ca ID W D

csi .-i

o re

c0 .0 4' c‘i CY ui IX u-

* * * * * *

40

O ...... .....The results of spring impingement survival testing are limited due to the very low abundance of fish at times when samples could be taken. Tests conducted in the April 13 to April 15 period were terminated prior to the normal 96 hour holding period due to operational problems with the fish holding facility water supply. These shorter term (24 hour) holding results indicated good survival of flounder and poor survival of smelt (Table 4). Later impingement survival testing resulted in a limited collection of test specimens, especially in June. Fish impingement on the Unit 7 screens was extremely low at this time. Latent survival results show good survival of sticklebacks, flounder, pipefish, and eels and poor survival of smelt (Table 5). SUMMARY OF TEST RESULTS Previous studies of winter flounder survival after impingement on the unmodified Unit No. 7 traveling water screens showed 85 percent survival with continuously rotated screens and 55 percent survival with 2-hour screen wash intervals. The data from the present study show an improved survival of winter flounder impinged on the modified screen, and a virtual elimination of mortality when the screens are continuously rotated at all speeds during the period of peak abundance in the winter. Survival of Alosa and smelt was lower than that of winter flounder. These species are difficult to maintain under laboratory conditions and overall survival would probably exceed observed values if these fish were to be returned directly to the river. In addition, differences in survival due to screen speed for Alosa and smelt are not as dramatic as those for winter 10Winterflounder U 0 rl ORainbowsmeltNorthernpipefishThree-spinesticklebackAtlantictomcodRESULTSOF24-HOUR

r-I (0 41 •rl U 41 S-1 0 (xi cn

0 4-) co 4-i 0 o a) •ri Q.I U 4-) $.4 a a cn $-1 O 0:1) cct I e a Csi Z S-I 0 $-1 0 4) 01 I .1-1

A e )-1 N Z

= • -..t 0

0 0

0 0 0 0 11 1-1 a 0 0 0 1

- 1 r-I 0 0

0 a. 0 1-1 00 0 0 1-1 r-I 0 0 0 CO ri es/

0 r-i

0 a r-1 r-I

0 0 0 0 1-1 o0 0 0 1-1 1-1 0 0 N

0 0 0 r-I r-I

0 r-I 1-1

0 \O 0 CO \O .1' N N 0 N

,-, , 4., tz a3 0 • r-I cu •r-I .,-1 $.4 $.4

0 0 1

- 1

o o o r

- I r

- 1

co c). o v

- 1

o o o 11

o as co 0 cU 0

I

- 1 114 C/3 r1 cd $4 • ,

- ) a) 1 0 ,JO 4

- ) MI a) O O o r1 co o o cn Ln 0 a A 1-1 Z 1- 1 N v-i r-i \O \O N N cr) cn cn cn cn cc) Ln cn in cn Ln in WI Cl in in In Cl

cn ,-1 ,-.1 r-1 ,--1 ri ,-I ,-1 ,-1 O 41 LI-I • H 3-4 cc)3 CIJ V) CI) 0 0 r--1 0

cn -O ,--, LIeciesNameJ •••• • :( /-• > Z I-1 UJ : 5 FIX Ct 01 -1 CD CD CD CD C3 CD CD CD 0 Ch CD 0 01 CD CD CJ CD CD 0 C) 0 CD 40 CD C) • 0 • • • • • • • • • • • • N DC CD CD 111 CD CD CD CD CD C5 r - 0 CD -J N CO 00 00 -J ‹C ri r4 ri ri ...I I-1 cX /- CY I-1 UJ Z >/-I C) ,, _J At CD C) CD CD C3 CD CD 0 CD Ch CD CD h7 CD CD CD CD CD CD CD CD cn 43 CD CD Z hi • • • • • • • • • • • • • • ILI > C C r

51 D D C a D D r , 00 I - re OD CD CD CD CD < 0 .-4 ri ri ri -1 01 CI Et ILE D C) ri hl ri CO ri r4 • • 0)N • • • • /-1 1 LU O CO Ch• O W > t••• EX 14 >- D -1 O . r 0 CC

• • hq

• 4' . r4 0J • ri CV ri i

• • Z D I Ill 0 ›- 0,

/0 CO 0

- Z Z 0

( ) < Z z F - a I -: -J ,_, z ..... 4i0 >. < Z 0 _J <

-J UJ cn CD C) CD CD CD CD CD 0 CD 0 CD CD CD 1--

..... D L) Q> CD CD CD CD CD CD C) CD CD CD CD CD CD CD H hi • • • . • • • • • • • • • • LO :5 /-- > CD CD CD CD CD CD CD CD CD CD CD CD CD CD 11) Z CE

I Z hi CP.' CD C5 CD CD CD CD CD CD CD CD CD CD H 0 Z :D r4 ri r4 ri rl ...I ri 1-4 ri ri ri ri

W IX hi tr) -J CL (i)

• Z (1) on In 0 1-1 a c3 )-- IL I

- I a < I- I

- - Li.1 -J W vi Z -.I

ri I

- 1 F - Lij I - Z 1 , -- ce

r4 Pi UJ X ... N W 1 , 1 5 J 0 z rt) .., "" I- hi D t e j u ( n z z ,, 0 CL 1— >

m 11.1 (f) -.I

hi _J

r i

• II X 14 ri hl 111 CV L1 pi r4 pl cla NI cu ri • • i ri pi -- IY 1-I LU Z 0) /-1 0 ✓ a mi, (a c. pl CD 0 PI CD hl 0 hl CD hl 0 UJ . . . . • . . . . . . • . . IL1 pl Lin ul ri ul ul PI Li mi ill hl ul pl CO EL ri ri ri ri ri ri ri ri 01 •••• •---- X X 0 U <E •zt X 3C 0)10 U U WW .1 <X D D CO in .--I -J Ill LA.1 'CO CO JJ Z 3: 2 XX

++ Eu co co 0 0 EX EX 0 I-i i-I I-I 1-4 CI

CU Ul LU UJ CC IS. IL. I- I- 0 U. U- ra ra a: LU LL1 h- h- CO 01 C) H 1-4 -.I 7:ZZ as -J-1 2 Z uJ 0 0 cu 1- ■ i-i u) cu EU III 0 2 U) Will 0 CD ::: CL CL :: 1: Z Z F- U -J -J -1 -J 01 01 hi hi re 4 cr z LL I. C) 2: 2: 0- EL El W

01 .., --, CC hi Et EY X :C CO CO Fl EL UJ EJ IX EY I- W WOO I I hhi cr ci. 1-1 W W 2: 2 3: CO CO W W Z W L) 11-1 V) 01 Et I- F- <X F- I-- 2: 2: Eci co <X Icu :: C) ca w 2: 2: -J re re hi hi CY IX -J 1-I CL Ct -J -J 7: 1-4 hi h- C) 0 <X <X 32 X F- 3: N:: <X <X <X X 2C <X z 2: rx ce F.- F- <X BCflounder. Regardless, small Alosa and smelt of all sizes displayed moderate survival at screen speeds of 15.0 ft/min in fall and winter. Less abundant species such as tomcod, stickleback, sculpin, mackerel, mummichogs, and cunner appear to have good survival potential at any screen speed. An interesting and very positive general conclusion is that species show high survival when they are abundant. DISCUSSION It would appear from the results of this study that a modified, traveling screen system offers an effective means of alleviating fish mortality at Mystic Station - Unit 7. Should such a system be incorporated as a permanent solution to impingement losses, the engineering implications of continuous operation during periods of fish impingement should be considered: 1) Continuous screen operation reduces the life of screen components, 2) Increasing speed of screen rotation under a continuous operating mode increases the rate of wear of screen components. Since these factors have a major impact on maintenance requirements and operating costs and can jeopardize unit reliability, every attempt should be made to minimize the duration and speed of continuous screen operation. 11Based on the seasonal patterns of impingement noted in this study (refer to Table 1), as well as those observed in past impingement monitoring studies at Mystic Station, it appears that a major portion of the fish impinged could be protected by operating modified screens at Unit 7 on a continuous basis for only several months each year. While impingement sampling was not conducted from April 27 to June 1, it was evident from observations at Unit 6 during this period that numbers of fish impinged remained at the low level observed for the prior ten weeks. Historically, the number of fish impinged at Mystic Station from June through September is very low, while jelly fish (Aurelia aurita) are in abundance. Therefore, it is believed that the impingement numbers presented in Table 1 represent the majority of the fish impinged at Unit 7 on a yearly basis. Using these numbers, it is clear that two peaks in impingement of the four species of concern occurred. The periods of high abundance were short in duration, while the remainder of the year numbers were low. As shown in Table 6, at least 80 percent of each species occurred during the two seven week periods of October 21 to December 8 and December 30 to February 16. Therefore, if modified screens had been run continuously during fourteen weeks of the year, protection would have been afforded to a large percentage of the fish collected during the entire year. While the periods of peak fish abundance at Unit 7 vary in time from year to year, impingement data gathered over a number of years show that definite peaks occur each year. Therefore, should modified screens be utilized at Unit 7, it is recommended that they only be run continuously during periods of peak abundance. Such an operational mode would provide a high degree of fish protection in a cost-effective manner while limiting the potential for 12TABLE 6 Percent of Total No. Collected During Species Period of Peak Abundance the Two Peak Periods Rainbow smelt December 30 - February 16 90 Alosa spp. October 21 - December 8 93 Winter flounder December 30 - February 16 80 TABLE 7 Mean Percent Survival During Period of Peak Abundance by Screen Speed Species Size Low Medium High Rainbow smelt Large 11.0 31.3 40.0 Small 22.5 58.3 66.7 Alosa spp. Large 0.8 0 0.5 Small 6.7 23.4 48.1

Winter flounder All 96.8 100 98.6problems associated with operation, maintenance, and general reliability. Since the peak periods of fish abundance at Mystic Station are distinguishable from periods of lower abundance, the decision to operate continuously could be made on the basis of periodic observations during intermittent operation. A final consideration in employing modified screens at Unit 7 would be the speed at which to rotate the screen during times of continuous operation. As shown on Table 7, higher survival was obtained at the highest speed than at the lower speeds. It would appear that the lowest speed would achieve a high level of survival with flounder only. On the other hand, the intermediate and high speeds both resulted in good survival for most species tested. The final decision to run at a specific speed must take into consideration engineering reliability and cost considerations, as well as survival. The engineering implications of operating at higher speeds involve greater wear of the rotating parts of the screens: the rollers, bushings, and pins of the chains; the foot shaft and headshaft bearings and bushings; and the tooth-inserts on the sprockets. Wear of these components increases exponentially with screen speed. Wear of the rotating components results in slack in the chains and the interference of the baskets with the bottom boot plate where the baskets rotate around the foot shaft and sprockets. This can result in breaking away of the basket, jamming of the traveling screens, breakdown of the tooth-inserts, and breaking of the chains (Mussalli et al. 1977). 13Wear of the screens can lead, therefore, to increased maintenance costs and jeopardize unit reliability. The estimated incremental maintenance cost for high speed versus medium speed operation of two modified screens at Mystic Station - Unit 7 would be $5,000.00 annually based on 14 weeks of continuous operation. This cost includes materials and labor to replace the footshaft and headshaft bushings and bearings and the chains approximately every five years. Potentially more important than routine maintenance costs would be the major costs associated with a unit outage resulting from equipment failure due to high screen speed operation. The specific drawbacks of operating a modified screening system at Mystic Station - Unit 7 at a high travel speed rather than medium speed can be summarized as follows: 1. Wear of screen components would be four times greater at the higher speed, 2. Annual maintenance costs would be higher, 3. The reliability of Unit 7 would be placed in greater jeopardy, and additional costs could be incurred due to unit outage as a result of equipment failure, 4. Flounder, the most valuable commercial species, are afforded equal protection at all operating speeds. 14For these reasons, it is recommended that modified screens be operated at intermediate travel speeds should they be required at Mystic Station - Unit 7. Considering the relatively low commercial value of Alosa and smelt, the costs and potentially high reliability risks of high-speed operation would not be warranted. During periods when flounder are the only abundant species even intermittent (Stone & Webster 1978) screen operation would afford an adequate level of protection. LITERATURE CITED Steel and Torrie. 1960. Principles and Procedures of Statistics. McGraw-Hill, New York. 481 pages. Stone & Webster Engineering Corporation . 1978. Fish Impingement Monitoring, Mystic Station - Unit No. 7. July 1978. 54 pages. Mussalli, Y. G., Taft, E. P. III, and Hofmann, P. 1977. Engineering Implications of New Fish Screening Concepts. Proceeding of the Fourth National Workshop on Entrainment and Impingement, Chicago, Illinois, December 5-7, 1977, pp. 367-376. 15