MaoDcC I'lo : Eq*7) 11-
TECHNICAL REPORT TO THE CALIFORNIA COASTALCOMMISSION
D. Adult-EquivalentLoss
MARINE REVIEW COMMITTEE. INC.
William W. Murdoch.Chairman Universityof California ByronJ. Mechalas SouthernCalifornia Edison Company Rimmon C. Fav PacificBio-Marine L;ibs, Inc.
Preparedby: Keith Parker EdwardDeMartini ContributineStaff: BonnieM. WiJliamson
October1989
I
I TABLE OF CONTENTS
I SUMMARY ...... v 1.0 INTRODUCTION.... 1
I 4 Estimation of reducedrecruitment of new adultsdue to I entrainmentof immature stages 2.1 Basicmethod for estimatingadult-equivalent loss...... 5 2.l.L Compensationignore?..... 6 2.1,.2Loss to the adult standingstock 6 I 2.2 Estimation of entrapmentprobabilities 7 2.3 Estimation of entrapmentiates 8 2.3.1 Entrapmentrate for plankton... 9 I 2.3.2 Entra-pmentrate for iuveniles... 13 2.3.3 Duration of the stagds. 15 I 3.0 RESULTS T7 3.1 Ta: I APPENDICES I APPENDIXA: EstimatingEntrapment Rate For PlanktonicStages A-1 APPENDIX B: EstimatingAdult StockSi2e...... B-1 I APPENDIX C: EstimatingThe EntrapmentRate of Young Adults c-1 APPENDIX D: EstimatingJuvenile Entrapment Rate... D-1 I APPENDIX E: EstimatingDuration At Rick For PlanktonicStages E-1 I I I TABLE OF CONTENTS- APPENDICES APPENDIXA: EstimatingEntrapment Rate For planktonic stages 4.1, Data collection A-1 A.2 Intake1oss...... A-2 4.2.1, Intake lossfor taxanot affectedbv SONGS. A-2 A.2.2 Intakeloss for taxaaffected by SONGS...... A-3 A.3 Standingstock in the bight...... A-4 +.1.1 Standingstock foi taxanot affectedby SONGS...... A-5 +.3_.?Standing stock for taxaaffected by SONGS A-6 A.3.3 Standingstock of northern anchoi'y. A-7 A.4 EntrapmentRate...... A-7 A.5 Major a_ssumptionsin estimating entrapment rate...... A-8 A.5.1 Usingimpact and control-datafor taxanot affected...... A-8 4.5.2 Interpretingand estimatins SONGS'effect...... A-9 A.5.3 Usingimpalt datafor affeited taxa...... A-lz A.5.4 Meansover time A-13 A.5.5 No standingstock bevond E,Block.... A-14 A.!.q Ioss is profortionateacross all depthstrata...... A-15 A.5.7 Equal effeit acrossall stases ,4'-16 A.5.8 Pri:cisionof adult-equivalEnt1oss...... ,4.-16 REFERENCES - APPENDIX A A-L7 TABLES A.1 - A.3.. A-19 APPENDIX B: EstimatingAdult StockSize 8.1 Introduction... B-1 8.2 Queenfishand white croaker: eggabundance and production...... B-3 8.2.1 F;ggabundance ...... :.: B-3 8.2.2 Daily eggproduction ...... B-4 B.3 Queenfishand croaker: Batchfecundity.. B-5 8.4 Queenfishand croaker: Spawningfraction..... B-6 B.5 Queenfishand croaker: Femalefraction B-6 8.6 Northernanchow stockestimation B-7 8.7 Estimatesof adult stocksize B-7 8.7.1 Northernanchow B-7 8.7.2 Queenfish...... :. B-8 B.7.3 White croaker B-8 B.8 Potentialinaccuracies: Factors affecting stock estimates B-8 REFERENCES - APPENDIX B B-10 TABLES 8.1 - B.7 B-15 APPENDIX C: EstimatingThe EntrapmentRate of young Adults C.1 Introduction...... c-1 C.2 Inplant lossand bight-wideabundance of youngadults c-1 C.3 Taxaaccount: Discussion of problemdata and assumptionviolations ...... c-4 C.3.1Northern anchovy.... c-4 C.3.2 Queenfish...... :...... c-4 C.3.3 White Croaker c-5 C.3.4 Taxawith inplantlosses estimable for old iuveniles c-6 C.3.5Taxa with inillantlosses inestimable for juieniIes...... c-7 C.3.6 Generalpatterns for all taxa..... c-7 REFERENCES- APPENDIX C...... c-9 TABLESC.1 - C.5 c-l1 APPENDIX D: EstimatingJuvenile Entrapment Rate... D.1 Outlineof methods...... D-1 D.2 Minimum and maximumlength, availability and vulnerability for queenfishand white croa-ker.... D-3 D.3 The shapeof availabilityand vulnerability functions...... D-7 D.4 Summary...... D-12 REFERENCES. APPENDIX D...... D-1,4 TABLE D.1 D-17 lll APPENDIX E: EstimatingDuration At Rick For planktonic Stages E.1 Estimatingrange in bodylength of a stage E-1 E.2 Growthrate...... E-2 E.3 Durationin time at stage...... E-2 REFERENCES- APPENDIX E...... F-4 TABLESE.I.E.2 E-9 lv I I SUMMARY I In this report we estimatethe loss of adult-equivalentfish due to entrapmentby I SONGS'Units 2 and3. We definean adult equivalentas a fish that would haverecruited to the adult stock had it not been entrapped as an egg, larva, or juvenile. We estimate I adult-equivalentloss in terms of 1) percent of new recruits and?) numbersand biomassof the standingstock. The first estimate,percent of new recruits,is an annual rate. This we I estimatefor2'l' ta,ra.The second,lossto the standingstock, is for all year classescombined I and requiresthe accumulatedeffect of plant operationover the number of yearsequal to the oldestfish in the stock. I I Percent of New Recruits I The percent of new recruits lost is highest for those taxa with the highest proportionsof planktonicand juvenile stagesfound in watersnear the depth of SONGS' I intakerisers. Of the 2J.twCalifornia halibut, I whoseplanktonic and juvenile stagesare not at great risk to entrapment,have the lowest I estimatedloss, all lessthan 0.2Vo. I Numbersand Biomass T We estimateloss to the standingstocks of adults for three taxa, those for which we could estimate adult abundance. Lossesare 551 MT (18,000,000fish) and 394 MT I (4,100,000fish) for queenfishand white croaker,respectively. Estimated loss of northern I I anchovyis 1,340MT (89,000,000fish). Thesethree taxaaccount for approximately70Vo of all entrainedlarvae and togethersum to total lossof over2,290MT. t I 1.0 INTRODUCTION I SONGS' Units 2 and 3 draw in approximately6.8 million cubic meters of I water per day. This equalsthe volume of a seawatertank with a basethe size of a football field and a height of over one-half mile. Entrapped with thesewaters are I adult and juvenile fish, larvae, and eggs. Some entrapped adults and juveniles (sexuallyimmature fish) are impinged or otherwisekilled. The fish return system I may allow a significantportion of older juveniles and adultsto survive(DeMartini er I al. t987;l-ove et al.1987). All entrappedlarvae and eggsare killed (Barnett 1987). I In this report we evaluate the potential effects of SONGS' entrapment of eggs,larvae, and juveniles on stocksof adult fish living in the California Bight, the I body of water extending from Cabo Colnet, Baja California, Mexico to Point I Conception. We call this estimate"relative adult-equivalentloss," or simply "adult- equivalentloss." We define an adult-equivalentas a fish that would have recruited I to the adult stock"had it not been entrappedand killed as an egg,larva, or juvenile. We estimate adult-equivalent loss for 2l tu 2.0 METHODS I I Estimation of ReducedRecruitment of NewAdults due to Entrainment of Immature Stages I SONGS'intake risers sit at approximatelythe 9 m depth contour and rise 4 I to 5 metersfrom the bottom. SONGS entrapsimmature fish (juveniles,larvae, and eggs)which live near this depth. The higher the proportion of a ta:ron'spopulations I of immatures found in waters at this depth, the greater the relative risk to entrapment. Thus for taxa like queenfish,where the older larvae and juveniles are I found almost exclusivelyin waters at this depth, the risk is high. For taxa like I northern anchory, where these planktonic stagesare also abundant offshore, the relative risk to the population is less,despite the fact that SONGS entrapsgreater I numbersof the eggs,larvae, juveniles queenfish. and of anchoviesthan I The design of the MRC's (1988a) ichthyoplankton sampling program providesa useful meansfor illustrating relative risk. The MRC sampledthe density I of ichthyoplanktonin five cross-shelfblocks (A, B, C, D, and E, Figure 1). The I intake risers sit at approximatelythe boundary of A- and B-Blocks, L.1,km from shore. SONGSentraps waters from both theseblocks (ECOsystems1988). Data I (presentedin RESULTS) indicate that for most taxa consideredin this report, the populationsof eggsand larvaeare not found beyondE-Block. (Northern anchovyis I an exception.) Thus, the higher the proportion of A- through E-Block immatures found in A- and B-Blocks,the higher the relative risk to entrapment. Additionally, I longer-lived stageshave longer exposureto entrapment and are at higher risk. I FollowingMacCall et al., we usethis basicidea of risk beinga functionof (1) cross- shelfdistribution, and (2) time at risk, to estimateadult-equivalent loss (following). I I I I I 2.1 BasicMethod for EstimatingAdult EquivalentLosses I The basis of our projectionsof adult equivalent lossesis the following I calculations,given by McCall et al. (1983). I Supposethat, without SONGS,the probability of survivingthe ith immature stageis pi. This is the ratio of the number entering stagei to the number entering I stagei+ 1.. If there are k immature stages(including eggs),the probability of a new- I born eggsurviving to adulthoodis the product,prpz...pr. I With SONGS in operation, surviving the ith stage requires avoiding both natural mortality and entrapment. If the natural rates are unchanged,and the t probability of avoidingentrapment in the ith immature stageis gr, the probability of surviving the ith stage is the product, piQi. The probability of a new-born egg I survivingto adulthoodis now prerpzez...prgr. I The new rate of recruitment, expressedas a fraction of the old rate, is the I ratio of the post-SONGSto the pre-SONGSprobability. This is the product of the T probabilities of avoidingentrapment, = = -Er)(1 -Ez)...(l-E*), I R" qrqz...ek,(1 where E is the probability of an entering stage i fish being entrapped before I reachingstage i + 1. The fractional lossin recruitmentis then l. - R". I I I I I 2.l..L CompensationIgnored I I These calculations assumethat natural survival rates (pr, p2, ..., pt in the descriptionabove) do not change:that there is no compensationas the densityof I immaturesdeclines. This is deliberate. Our airU is to determine the reductionsin recruitment rates of new adults implied by the uncompensatedkilling of immature I stagesby SONGS. These overall rate reductions combine the effects on the different life stages,to summarizethe direct effect of SONGSon the populations. I I In addition, the calculation of these reductions will later become an intermediate step toward the calculation of the change in fish stocks,when I compensationiS considered(see Technical Report M). When the new equilibrium population is reached,at which SONGSlosses are matchedby the increasedgrowth, I fecundity or survival of the individuals not killed by SONGS, rates of adult recruitment and of adult mortality must again be equal. Except for any I compensationvia adult survival, this implies that, when the new equilibrium is I reached,the rate of recruitmentto the adult populationis againwhat it wasbefore SONGSbegan. t 2.1.2 Inss to the Adult StandingStock I I To give a feeling for the amount of loss implied by the fractional loss,we estimatethe lossto the adult standingstock to be I Adult I-oss= (Fractionalloss) x (CurrentStanding Stock) I = (1 - &) (CurrentStanding Stock). " I I t I I This calculation assumesthat the total number of eggsproduced per year I remainsconstant. Sincethe number of adults has been reduced,this assumptionis one of compensation:the number of eggsproduced per adult must increasewhen I the adult population declines. Some such assumption is needed: without I compensation,the standing stock would decreaseeach year, and the adult loss would decreasewith it, eventuallylo zero. I The adult lossdescribed here is not the lossin new recruitseach vear. This I lossis t RecruitsLost = (1 - R") x (Pre-SONGSnumber of recruits). t The adult standing stock is composedof more than one year class, so it I contains not only the most recent set of recruits, but also the survivors from the recruits of earlier years. Thus our calculation assumesthat SONGS has been I operatingsince before the birth of the oldest fish in the stock,so that all year classes I have been affected. All rates other than egg production are assumed to be unchanged. I t 2.2 Estimationof EntrapmentProbabilities t We now turn to the problem of estimating the probabilities of avoiding entrapment,er, ez,..., ek. I First we define the "instantaneous"probability of entrapment for a fish in I stagei to be I I I ei = (fraction of stage i fish entrapped in time t)/t, I when t is verv small. T It can be shown that, if ei is constant throughout the ith stage, the probability I of avoiding entrapment for T time units is exp(-e;T). In particular, if the duration of I the ittt stage is di time units, the probability of avoiding entrapment through the entire stage is I Ei = exp(-eidi). I If ei is not constant through the stage,the same formula still holds for Ei, T exceptthat "ei" must now be interpreted as the averageentrapment. Technically,if I the entrapment rate for immaturesof aget is e(t), then t €i = I e(t)dt/d1 the integral being from t = !, the beginning of the stage, to t = ti * di, the end. T t Thus,E can be estimatedby substitutingestimates of ei, the entrapmentrate, and d;, the stageduration, in this relationship. I 23 Estimation of Entrapment Rates I The instantaneousprobability of entrapment, per day, for any stage is t estimatedas I * ei=L/S where I I I t I L = estimatednumber of stagei entrappedper day I and I S = estimatedtotal number of stagei in the population. I The "population"is taken to be the populationof the SouthernCalifornia Bight, defined as extendingfrom Cabo Colnet, Baja California, Mexico to Point I Conception,about 500 km (after Jonesi,g7r). while eggs,larvae, juveniles, and adults for many taxa consideredin this report extend both north and south of the I Bight, we use the Bight becauseit representsa natural ecologicaland economic unit. The immatureskilled by SONGSwill almost all have been born inside the I Bight, and the lossesare unlikelyto be significantoutside it. I 2.3.1 Entrapment t Ratefor Plankton In this sectionwe describethe estimationof L and S for plankton of a given I stage (referred to as "plankton"). The stages are (1) eggs (when they are planktonic),(2) yolksacand preflexionlarvae, (3) flexionlarvae, and (4) postflexion T larvae. I Sinceplankton appear to move passivelywith the water, the number killed I per daycan be estimatedby L = DsWs, I where I Ws - amountof waterwithdrawn by SONGSper day and I Ds = densityof planktonin the waterwithdrawn by SONGS. T t I I An estimate of the standing stock, the total number of plankton in the population,is given by I S = DBWg where I Ws = amount of water in the Bight I and Ds = averagedensity of plankton in the Bight. t For Ws we need the averagedaily intake volume for Units 2 and3: Unit 1 is I not covered in this Report, and it is the actual averageflow that determinesthe number of plankton entrapped,not the flow at full operation. Since 1984,this I averagedaily intake volume hasbeen 6.8x 1ff m3/day(MRC 1988b). Thus we take I Ws = 6.8 x 1ff (m3/day). I To estimate Ds and Ds, we use data collected by Marine Ecological I Consultants(MEC) at an Impact site near SONGS (1-3 km south of the intakes) I and at a Control site (18 km south). Thesewere analyzedfor 21.taxa, chosen either for their sport/commercialimportance or becausethey are highly at risk (have high I proportions of their populationsliving in entrappedwaters). I In 1978MEC collectedabundance data at the Impact site only. From 1.979 through 1986,abundance data were collectedat both the Impact and Control sites. t Each site was dividedinto 15 strata:five cross-shelfblocks (A B, C, D, and E) and I three depth zones (neuston,midwater, and epibenthos). MEC defined neuston as the top 0.16 m and epibenthosas the bottom 0.5 m. On each cross-shelfsurvey, I 10 l I I I eachof the L5 stratawas sampled. From 1983through 1986,samples from E-Block I were not analyzedin the laboratory. The MRC's (1988a)report on ichthyoplankton I describessampling and data analysisprocedures. t SONGS' Units 2 and 3 draw in watersfrom both A- and B-Blocks. Thus we estimatethe densityof plankton in the water withdrawnby SONGSas I I Ds = number per m3in A and B Blocks. This number per m3 is obtained by multplying the densitiesper m3 in the three I regions (neuston,midwater and epibenthos)by the relative volumes these regions t represent,i.e., (volume of region)/(total volume of A and B Blocks), and adding t theseproducts. Since most of the taxa consideredin this report are not found beyond E- I Block (Table 2), we estimatethe Bight-wide densityby the numberscontained in a I meter-widestrip running from the shore to the outer edge of E-Block, about 7 km offshore. Thus I Ds = number per meter-widestrip through BlocksA-E. I Since Ds is given in terms of meter-wide strips, Ws is the number of such I strips in the SouthernCalifornia Bight. The Bight is about 500 km long, so I Ws = 500,000. I I 11 I I I The estimates given here make several assumptions,the most important appearingto be: planktonic eggsand larvae move passivelywith the water, so the I number killed is the density in the water multiplied by the amount of water withdrawn; plankton in neuston,midwater and epibenthosare equally at risk; the I density over A-B Blocks is approximatelythe same as in the water withdrawn by I SONGS (which is near the boundarybetween A and B Blocls); anda meter-wide strip near SONGSis "typical"of the Bight, i.e.,it containsabout the samenumber of t plankton as the averageof suchstrips over the entire Bight. I A further assumptionis that plankton in A-B Blocks and plankton in C-E Blocks are equally catchable.' We do not need perfect catchability: as long as I catchabilityis the same,so that both Ds and Dn are underestimatedby the same I proportion, the ratio L/S is unaffected. I fn some cases,final estimatesrequired some assumptionsdue to gapsin the data. T I Eggs cannot be identified to taxon, except for northern anchovyand a few other speciesnot on the target list. But the egg stageis short, both absolutely(2.5 I days) and relative to the other stages,so we assumethat the distribution (i.e., Ds/Ds) is the samefor eggsas for yolksacand preflexion larvae. T For all stages,the estimatesof both the A-B densityand the A-E densityused I both pre- and post- operationaldata from both Impactand Control areas. SONGS I operation may have affected the abundanceof four taxa at the Impact site. For I T2 I I I I these taxa, we adjust for the SONGS effect using estimatesof relative change I presentedin the MRC's (1988a)report on ichthyoplankton. I E-Block sampleswere analyzed in the laboratory for the pre-operational I period,but not for the operationalperiod. We assumethat the fraction in E Block of the planktonin A-E Blockswas the samein the post-operationalperiod as in the I pre-operationalperiod. Thuswe take I Post-opA-E = Post-opA-D x [(Pre-opA-E)/(Pre-op A-D)]. I Further discussionand details of assumptionsand samplingmethods are I given in Appendix A. I 2.3.2 Entrapment Rate for Juveniles I We definejuvenile as the stagefrom metamorphosis(end of the post-flexion t stage)to first sexualmaturity. Metamorphosisoccurs when fin rays and scalesare fully developed.For mosttaxa, juveniles mature at the end of the first year. I The methodsused to estimateplankton entrapment rates are not suitablefor I estimatingjuvenile ratesfor two reasons.First, juvenilesdo not move passivelywith the water: they can resistentrainment, and this ability increasesduring the stage,as I the fish gets bigger. Second,we have no data on juvenile densities:quantitative I methodshave not beendeveloped to sampleearly juvenile stages. I I 13 t I I For some ta>(a,e.9., cryptic reef dwellers and some benthic fish such as blennies,juvenile stagesdo not inhabit water near the intake openings,so are rarely, T or never, entrapped. There is significantjuvenile entrapment for only 9 of our 21. ta:(a. I I For three of the taxa whose juveniles are entrapped (northern anchovy, queenfish and white croaker), we are able to provide approximate estimatesof I entrapmentrate, using information on post-flexionlarvae and young adults. These estimatesassume that densitynear SONGS ("availability")and probability of being t unable to escapefrom water that is being drawn into SONGS ("wlnerability") change during the juvenile stage, as a function of length, from those of the I postflexionstage to thoseof youngadults. I Unfortunately, how these functions change is almost completely unknown. I This is only of minor importance for availability, since distributions of postflexion larvae are not very different from those of young adults in these cases. But the I function is of major importance for wlnerability, which changesgreatly between I postflexionlarvae (vulnerability = 1) and young adults (vulnerability - 0, although the high availability of some speciesresults large absolute numbers of entrapped I individuals). Whether the bulk of the change from postflexion wlnerability to young adult vulnerability occursearly or late in the juvenile stagehas a very large I €ffect on the juvenile entrapmentrate. Also, sincethe juvenile stageis much longer than all the other stages,changes in the juvenile entrapment rate lead to very large I changesin the overall adult equivalentloss. I I L4 I I I t In Appendix D, we give high, middle and low estimates of juvenile I entrapment rates, based on different guessesat the wlnerability function. These guessesare guided mainly by the velocity of water at the intakes and by the known I relations betweenbody length and "burst speed",the maximum swimmingspeed of I the fish. I For the remainingsix taxa whosejuveniles are entrapped,these approximate methodsare not possible:we cannotestimate the entrapmentrates of youngadults I becausewe cannot estimatethe standingstock. For these taxa, we estimate adult I equivalentloss through the postflexionstage only. This clearly underestimatesadult equivalentloss. t 2.3.3 Duration of the Stages I Duration (di) is the length of time (in days) a given life stagei is at risk to I entrapment., I For all eggswe use a duration of 2.5 days,the averageembryonic period of I small,pelagic marine fish eggsat about 16Cb (W. Watsonpers.comm.). I For all other planktonic stages,we estimateduration in daysby dividing the I rangein length at stageby daily growth rate. I We estimate ranges in length at stage by subtracting modal lengths of successivestages: I I 15 I I rangeof lengthfor stage' = (modallength)i+r - (modallength)i. I We feel that differencesin modal lengthsgive us estimatessimilar to differencesin I initial lengths, since modal lengths at stage,i and i+ 1 both overestimateinitial length. I I We obtain estimatesof daily growth rate, as well as estimatesof length at hatchingand metamorphosis(the beginningand end point of the larval stage)from I publishedliterature. I Appendix E gives further details on the estimation of the durations of planktonic stages. t I I I t l I I I I T6 I t I I 3.0 RESULTS t We discussthose taxa whosejuvenile stagesare entrapped(Section 3.1) and I thosewhose are not (Section3.2) separately.Of the nine ta:rawhose juvenile stages are entrapped,only for three (anchovy,queenfish, and white croaker) were we able I to estimate adult equivalent loss for the juvenile stage. For the remaining six of these nine ta,xa(black croaker, California corbina, California grunion, jacksmelt, I kelp and barred sand bass,and salema),we estimate loss through the post-flexion t stage only. Sincejuveniles are entrapped,we know that we underestimateadult- equivalentloss for thesesix taxa. I For 12 taxa,juveniles return to the adult habitat (usuallythe benthosor kelp t beds) following metamolphosis and are no longer susceptible to entrapment I (Section 3.2). For these taxa, we estimate adult-equivalentloss through the post- flexion stageonly. I In the following, most information on natural history comesfrom A Field t Guide to Pacific Coast Fishes(Eschmeyer et al. 1983). In Table 3 we present estimatesof adult-equivalentloss by stage,accumulated to that stage. Thus, the I tabulated estimatesof adult-equivalentloss for the flexion stageof white croaker, I for example,include the lossesfor preflexion,yolksac, and eggs. I In the following, Baja refers to Baja California, Mexico. t I T 17 I I 3.L TaxaWhose Juvenile Stages Are Entrapped I I Due to lack of data on entrapmentrate for juveniles,adult-equivalent loss is not estimated for the juvenile stage of six taxa (see Appendix D) which have I juveniles that are entrapped. These are black croaker, California corbina, California grunion, jacksmelt, kelp and barred sand bass, and salema. I Consequently,the estimated lost adult-equivalentsshown in Table 3 reflect loss through the post-flexionstage only and are underestimates. I I Black Croaker I Black croaker (Cheilotremasatumum) range from Pt. Conceptionto southern Baja. Most adultslive closeto shore,between depths of 3-15m. Their pelagiceggs l are entrapped. I Most larvae are found closeto shore,nearly l00Voinshore of E-Block (Table I 2). Lawae may move onshore as they mature, since the proportion in A- and B- Blocksincreases with age (Table 2). All post-flexionlarvae are found within A- and t B-Blocks. l A high entrapmentrate and relatively long duration for the post-flexionstage I yield an estimatedadult-equivalent loss of 3.9%o(Table 3). Entrapment rate of the post-flexionstage is high, relative to that for flexion and preflexion, but note that T this stage is of low abundance(Table 2), and is found on only five cross-shelf transects.The high entrapmentrate for post-flexionis, however,consistent with the I inshorehabitat of adults. I 18 I t I T We cannot estimate adult-equivalentloss for the juvenile stagebecause we I do not have estimatesof the bight-wide standingstock of juveniles and adults (see I AppendixesC and D). I California Corbina I California corbina (Menticirrltusundulatus) range from Pt. Conception to southernBaja, usually in shallow water along sand beaches. Their planktonic eggs I are entrapped. I Most larvae are found closeto shore,nearly 100Voinshore of E-Block (Table t 2). I-a.rvaeprobably move onshore as they mature, since the proportion in A- and B-Blocks increaseswith age, and almost all post-flexionlarvae are found within A- I and B-Blocks(Table 2). I Entrapment rate is high, but durations of stagesare relatively short. Still, I estimated adult-equivalent loss through the post-flexion stage is relatively high (2.6%; Table 3). Entrapment rate is high for the post-flexion stage relative to I flexion and preflexion, but note that it is based on only four cross-shelftransects (Table 2). The high entrapmentrate for post-flexionis, however,consistent with the t inshorehabitat of juvenilesand adults. t We cannotestimate adult-equivalent loss for the juvenile stagebecause we I do not have estimatesof the bight-widestanding stock of adults (seeAppendixes C and D). I t T9 I , I California Grunion I I California grunion (Leuresthestenuis) range from San Franciscoto southern Baja, inshore to a depth of 18 m. Eggs are buried in intertidal sand and are, I therefore,not entrapped. I Most larvae (approximately80Vo) are found inshoreof E-Block (Table 2). l SONGSmay haveincreased the abundanceof grunionlarvae at the Impact I siteby 170Vo(Table A.1). We increaseentrapment rate to accountfor this increase in density (see Appendix A" SectionsA.2.2 and A.3.2). Through the post-flexion I stage,the estimatedadult equivalentloss is 4.6Vo(Table 3). tlf we do not adjustfor SONGS'effect,adult-equivalent loss through post-flexionis L.7Vo (using methods of t AppendixA" SectionsA.z.L and4..3.1).1 I We cannot estimate adult-equivalentloss for the juvenile stagebecause we t do not have estimatesof the bight-widestanding stock of adults (seeAppendixes C and D). I Jacksmelt I T Jacksmelt(Atheinopsis califumiensis)range from Oregon to southern Baja. Eggsare attachedto benthic algaeand are not entrapped. Approximately 95Voof I the larvae are found inshore of E-Block (Table 2). Moderate entrapmentrates and durations of planktonic stagesyield an estimatedadult-equivalent loss through the I post-flexionstage of 2.5Vo(Table 3). I 20 I T I t We cannot estimate adult-equivalentloss for the juvenile stagebecause we I do not have estimatesof the bight-widestanding stock of adults (seeAppendixes C I and D). I Kelp and Barred SandBass I These two taxa are combined because their larvae are indistinguishable. I Kelp bass (Paralabraxclathratus) range from Oregon to southern Baja and I are usually found in or near kelp beds and rocky reefs. Barred sand bass (Paralabrm nebulifer) range from central California to southern Baja, usually on T sandybottom amongor near rocks. Their planktonic eggsare entrapped. I Only a small fraction of larvae are found in A- and B-Blocks (Table 2). Consequently,larvae of these bassesare at relatively low risk to entrapment I comparedto other taxa. Estimated adult-equivalentloss is relatively low through I the post-flexionstage (0.08Vo;Table 3). Even 0.087omay be an overestimate becausethe population of larvae probably extendsbeyond E-Block. If this is true, I we have underestimatedthe denominator of entrapment rate, and overestimated t adult-equivalentloss. We cannotestimate adult-equivalent loss for the juvenile stagebecause we I do not haveestimates of the bight-widestanding stock of adults(see Appendixes C I andD). t T 21, I I Northern Anchory I I Northern anchovy (Engrautismordax) are pelagic fish that range from southernCanada to southernBaja. Their planktonic eggsare entrapped. I OnIy a small fraction of larvae are found in A- and B- Blocks (Table 2). I I-awae extend well beyond E-Block, although there is some indication that larvae move towards shore as they mature, sincethe fraction in A- and B-Blocks increase l from preflexion to post-flexionstages. I SONGS may have reducedthe abundanceof northern anchovylarvae at the l Impact site by 27Vo(Table A.1) and we adjustedentrapment rate for this reduction in density (seeAppendix A" SectionsA.2.2 and A,3.2). Through the juvenile stage, t the estimatedadult equivalentloss is lessthan 0.10Vo(Table 3). [If we do not adjust for the reduced density near SONGS, adult-equivalentloss through the juvenile t stage is still less than 0.t0Vo (using methods of Appendix A SectionsA.2.1 and t A.3.1).1 I Queenfish l Queenfish (Seiphus politus) range from Oregon to southern Baja and live t inshore and occur abundantly to depths of 21 m. Their planktonic eggs are entrapped. Larvae probably move onshoreas they mature, since the proportion in I A- and B-Blocksincreases with age (Table 2). 95Voof post-flexionlarvae are found in A- and B-Blocks.Estimated adult-equivalent loss is 5.4Vothrough the post-flexion I stage. High, middle and low estimatesof entrapmentrate through the juvenile stage t 22 t I I I are estimatedin Appendix D. An averageestimate of adult-equivalentloss through I the juvenile stage (based on an averageof loss for critical lengths of 4 and 5 - Appendix D) is l2.7Vo. This relatively large estimateof adult-equivalentloss is due I to both high entrapmentrates and long durationsfor post-flexionand juvenile stages I (Table3). I Salema I Salema(Xenktius califoiensis) range from central California to Peru, and are t found in kelp bedsand other rocky reefs. Their planktonic eggsare entrapped. I Only a small fraction of larvae are found in A- and B-Blocls (Table 2). Consequently,salema larvae are at relatively low risk of entrapment compared to t other ta,xa.Estimated adult-equivalentloss is relatively low through the post-flexion t stage(0.36Vo; Table 3). I Even 0.36Vois an overestimate,as the population of larvae probably extends beyondE-Block. Thus we probably haveunderestimated the population at risk, the I denominatorof entrapmentrate, and overestimatedadult equivalentloss. t We cannot estimate adult-equivalentloss for the juvenile stagebecause we do not have estimatesof the bight-widestanding stock of adults (seeAppendixes C I andD). I I t 23 I t White Croaker t t White croaker (Genyonemuslineatus) range from Canadato southern Baja and are found inshore, usually shallower than 30 m. Their planktonic eggs are I entrapped. I While relatively high proportions are found inshore of E-Block, the proportion in A- and B-Blocksis lower than that for queenfish(Table 2). I I SONGS may have increasedthe density of white croaker at the Impact site by 67Vo(Table A.1). We increaseentrapment rate for this increasein density(see I Appendix Ao SectionsA.2.2 and A.3.2). Through the post-flexionstage, estimated ,l adult-equivalentloss is 3.8Vo(Table 3). [If we do not adjust for the increased density near SONGS, adult-equivalentloss through the post-flexion stage is 3.2Vo (usingmethods of Appendix AoSections A.2.1, and 4.3.1).1 l I High, middle and low estimates of entrapment rate are estimated in Appendix D for the juvenile stage. An averageestimate of adult-equivalentloss I through the juvenile stage(based on an averageof loss for critical lengthsof 4 and 5 - AppendixD) is7.5Vo. I I 3.2 TaxtWhose JuvenileStages Are Not Entrapped T Juveniles, of the following taxa, move to the bottom of kelp beds or otherwisebecome unavailable to entrapmentafter metamorphosis. I I 24 I I I t Anow Goby I Adult arrow goby(Clevelandia lbs) range from Canadato southern Baja and t inhabit estuaries,lagoons, and tidal sloughs. Their benthic eggsare not entrapped. Most larvae are found closeto shore;all larvaeare found inshore of E-Block, with a I high proportion in A- and B-blocks(Table 2). I SONGSmay havereduced the abundanceof arrow goby at the Impact site by I 40Vo(Table A.1). We adjustedentrapment rate for this reductionin density(see AppendixA" SectionsA.2.2 and A.3.2). The estimatedadult-equivalent loss is2.6%o I through the post-flexion stage,(Table 3). This relatively high loss results from a combination of high entrapment rate and the relatively long duration of the post- t flexion stage (29.6 days). [If we do not adjust for SONGS' effect, the adult- equivalent loss through post-flexion is 4.37o, (using methods of Appendix A, t SectionsA.2.1, and .4..3.1).1 I Blennies I Blennies (Hypsoblenniasspp.) are found from central California to southern I Baja. They occur in the shallow waters of the rocky intertidal zorLe,among oyster t and clam beds,and in other inshorehabitats. Their benthic eggsare not entrapped. I Only a small fraction of larvae are found in A- and B-Blocks (Table 2). Consequently, the risk of entrapment is relatively low and estimated adult t equivalentloss is low throughthe post-flexionstage (0.14V0;Table 3). I I 25 t I I 0.1'4Vomay be an overestimatebecause the population of larvae probably extendsbeyond E-Block. Thus, we haveunderestimated the population at risk (the t denominatorof entrapmentrate) and overestimatedadult-equivalent loss. I California Clingfish t California clingfish (Gobiesoxrhessodon) range from Pismo Beach south to I central Baja, and are found from the intertidal to a depth of approximately11, m. Their benthic eggsare not entrapped. Almost all lanae are found inshore of E- t Block (Table 2). Through post-flexion, estimated adult-equivalentloss is t.4Vo, largelybecause the duration of planktonic stagesis relatively short (Table 3). I I California Halibut I California halibut (Paralichthys califumicus) range from the state of Washingtonto southernBaja. Their planktonic eggsare entrapped. I Only a small fraction of larvae are found in A- and B-Blocks (Table 2). J Consequently,halibut larvae are at relatively low risk to entrapment comparedto I other taxa. Estimatedadult-equivalent loss is relatively low through the post-flexion stage(0.L1,Vo; Table 3). I Since about 80%oof the A- through E-Block abundancewas found in A- I through D-Blocks (Table 1), the larval population probably does not extend much t beyond E-Block. To the extent that larvae extend beyond E-Block, the estimated adult-equivalent loss of halibutwill be evenless. I 26 J T I I CheekspotGoby t Cheekspotgoby (Ilypnus gilberti) range from northern California to southern t Baja. Like the arrow goby, the cheekspotgoby inhabit bays, estuaries,and tidal I sloughs.Their benthic eggsare not entrapped. Most larvae are found close to shore. Approximately 95Voof all planktonic I stages are found inside of E-Block (Table 2). A high proportion of larvae I (approximately 80Vo) are found in A- and B-Blocks. Through the post-flexion t stage,the estimatedadult-equivalent loss is 3.04Vo(Table 3). l Pacific Mackerel I Pacific mackerel (Scomberjaponicus) are found worldwide in temperate and tropical seas. In North America, the Pacific mackerel ranges from Alaska to I Mexico. Their planktonic eggsare entrapped. I Only a small fraction of larvae are found in A- and B-Blocks (Table 2). Consequently,Pacific mackerel larvae are at relatively low risk to entrapment. t Estimated adult-equivalent loss is relatively low through the post-flexion stage I (0.08Vo;Table 3). I Note that 0.08Vois an overestimate because the population of larvae probably extendsbeyond E-Block. Thus we have underestimatedthe population at t risk (the denominatorof entrapmentrate) and overestimatedadult-equivalent loss. t I 27 t, I DiamondTurbot t I Diamond turbot (Hypsopsettaguttulata) range from northern California to southernBaja and are found on mud and sand bottoms,often in bays and sloughs. I Their planktonic eggsare entrapped. I Most larvae, approximately85Vo, are found inshore of E-Block (Table 2). Larvae may move onshoreas they mature, sincethe proportion of larvae in A- and I B-Blocksincreases with age; l00Voof post-flexionlarvae are found inshoreof E- t Block (Table2). l Although durationsof planktonic stagesare relatively short, estimatedadult- equivalentloss through the post-flexionstage is 2.1.Vo(Table 3). T Giant Kelpfish I I Giant kelpfish (Heterostichusrostratus) range along the U.S. west coast to southernBaja and are found among rocks with kelp and other algae,to a depth of I 40 m. Their eggsare attachedto vegetationand are not entrapped. I Most larvae,almost LAIVo,are found inshoreof E-Block (Table 2). 95Voof I post-flexionlarvae are found in A- and B-Blocks. I Estimated adult-equivalent loss is relatively high (6.9Vo;Table 3). This results from high entrapment rate and the long duration of the post-flexion stage ,l (Table3). I 28 l I I I HornyheadTurbot I Hornyhead turbot (Pleuronicltthysverticalrs) range from northern California T to southern Baja, on soft-bottomsfrom 9 to 200 m. Their planktonic eggs are t entrapped. Only a small fraction of larvae are found in A- and B-Blocks (Table 2). I Consequently,the risk to entrapmentfor hornyheadturbot larvae is relatively low I comparedto other taxa and estimatedadult-equivalent loss is relatively low through t the post-flexionstage (0.12Vo; Table 3). Again, 0.l2Vo is an overestimate of adult-equivalent loss because the t population of larvae surely extendsbeyond E-Block. Thus we have underestimated I the population at risk and therefore,overestimated adult-equivalent loss. ,l Kelpfi sh (Unidentifred) I Kelpfish (most likely Gibbonsiaelegans) range from Canadato central Baja. They live in subtidal rocky areas to a depth of 56 m. Their benthic eggsare not I entrapped. All larvae are found inshore of E-Block (Table 2). Estimated adult- I equivalent loss through the post-flexion stage is relatively high (5.0Vo;Table 3) becauseof the high entrapmentrate and the relativelylong post-flexionstage. l I I I 29 t I t queenfishand white croaker. However, we can approximatethe loss of northern anchovy,at least for planktonic stages,from lossesdue to planktonic stagesof I queenfish. We use queenfishfor this purpose rather than white croaker for two reasons.First, the densityof white croakerwas affectedby SONGS'operation while t the densityof queenfishwas not. Second,the data set for queenfish(especially for I the post-flexion stage) was more complete over the period of sampling, L978 through 1986,and more appropriatefor estimatingloss of northern anchovy. l In A- and B-Blocks,post-flexion northern anchory is 10 times as denseand t has1..5 times the durationof post-flexionqueenfish. Thus, approximately 15 ( = 10x 1.5) times more northern anchovy post-flexion larvae will be entrapped than I queenfish post-flexion larvae. Consequently, northern anchovy will lose l approximately 15 times more adult equivalents than queenfish, assuming the mortality rates of post-flexionlarvae of both taxa are equal. Post-flexionqueenfish I accountfor approximately30%o of all adult-equivalentqueenfish lost (Table 3), or 5,400,000adult fish. Thus, the adult-equivalentloss of northern anchory due to I entrapment of the post-flexion stage is about 81,000,000( = 15 x 5,400,000)adult fish. At 15 g/fish this equals1,215 MT of northern anchovy.Again, this calculation I assumes,equal mortality for the post-flexion stage of northern anchovy and I queenfishin A- and B-Blocks. While we do not havedata to test this assumption,it is reasonablethat post-flexionlarvae of similar size and found in the samehabitat I shouldhave similar mortality rates. I Earlier stages(flexion, preflexion, and yolksac) of queenfishaccount for I approximately10Vo of all queenfishlosses. In A- and B-Blocks,earlier stagesof northern anchovyare 3.5 times as denseand have 1..3times the duration of post- I 32 I I I t flexion queenfish.Earlier stagequeenfish account for approximatelyL,800,000 lost T adult-equivalentqueenfish. Thus, the adult-equivalentloss of northern anchovydue to entrapmentof theseearlier stages is about8,100,000 (= 4.5x 1,800,000)adult fish t or 120 MT. This calculation,like that in the previous paragraph,assumes equal T mortality for the earlier planktonic stagesof northern anchory and queenfishin A- and B-Blocks. Again,we do not havedata to testthis assumption,although it too is I reasonablefor the reasonsdiscussed in the previousparagraph. t Becauseof their short duration and relatively low abundancein A- and B- Blocks,loss due to entrapmentof northern anchovyeggs is trivial in comparisonto I the lossof larval stages. t Thus we estimate loss of adult northern anchory due to entrapment of T planktonic stagesis approximately89,000,000 fish or 1,340MT. This is equivalent to about 0.3Voof the averageadult stock (3.7 x 1010)weighing 534,000MT I (AppendixB, Table B.5) I We do not estimatethe lossof juvenile northern anchovybased on the lossof I juvenile queenfish. This would be inappropriate since we cannot assumethat entrapmentrates remain the sameas the two taxa mature into adult fish. The MRC I (TechnicalReport C, 1989)estimated an 87%ointake survivalof later-stagejuvenile northern anchovy. Thus, lossesto the adult stock due to entrapmentof older l juveniles may be relatively small. However, entrapment lossesof earlier juveniles I would add to lossesfor planktonicstages. I T JJ t I 4.0 DISCUSSION T I 4.1 Magnitude of Effects t SONGS'Units 2 and3 draw in approximately6.8x1ff m3/dayof water (when six out of eight circulatingpumps are operating). This equals528 meter-widestrips I of A- and B-Blocks per day (approximately 190 km per year). Taxa with high proportions of planktonic and juvenile stocksin A- and B-Blocks are at highestrisk t to entrapment,and therefore havethe highestestimated adult-equivalent loss. l In the following discussion,it may help the reader to understand the I magnitude of loss by converting percent adult-equivalentloss into a geographic context. This is accomplishedby multiplying the percent adult-equivalentloss times t the length of the Bight, 500 km. As an example, the 12.7Voloss in queenfish is t equivalentto killing all the agel queenfishof a given cohort that would be found in 64 km (= 10.97otimes 500 km) of shoreline. Note, we expectthe effect of SONGS I entrapment on planktonic and juvenile stages to be more widespread (hence, thinner) than this. Further, this shoreline equivalent assumesno compensationin I preadult stages;compensation in preadult stageswould decreasethis estimateof shoreline equivalent. We suggestthis geographiccontext simply as an alternate I means of interpreting the magnitude of adult-equivalent loss. We show the t shoreline equivalentsto adult-equivalentloss in Table 6. t I t 34 I I I t 4.1.1 TaxaWhose Juveniles Are Entrapped I We estimate adult-equivalent loss for nine taxa whose juveniles are t entrapped. Of these nine, queenfish and white croaker have relatively high estimatesof adult loss, l2.7Vo and 7.5Vo(Table 3). For each taxon, total lossesare I essentiallyequally divided between planktonic and juvenile stages. Total adult- equivalentloss is high for queenfishbecause of the relatively large fraction of the T post-flexionstage found in watersentrapped by SONGS'A- and B-Blocks. il For six of these nine, entrapment rates for the juvenile stage are not t estimable,and we estimateadult-equivalent loss through the post-flexionstage only. Three of the six have relatively low proportionsof planktonic stocksliving in A- and t B-Blocksand consequentlyhave trivial estimatesof adult-equivalentloss: northern I anchovy(less than O.LVo),kelp and barred sandbass (0.08Vo), and salema(0.36Vo). Even these relatively low estimates of loss are probably overestimates,since T planktonic stagesprobably extend beyond E-Block for both these ta,xa;adding in juvenileswill make little difference. Four of the six have relatively high estimatesof t adult-equivalentloss: Californiagrunion (4.6Vo),black croaker (3.9%o),California corbina (3.6Vo),and jacksmelt (2.5Vo). Since SONGS also entrapsjuveniles for t thesetaxa, these are underestimates. I However,we believe that adult-equivalentloss of the juvenile stageof these I six taxa is less than that estimatedthrough the planktonic stages,because as juveniles mature they move out of the area of high risk to entrapment. t Consequentlywe expect that the total adult-equivalentloss (for eggs,larvae and t juveniles) must be less than twice that through post-flexion for these ta:ra. We f, 35 T I I believe this for the following reason. For both queenfishand white croaker,whose planktonic,juveniles and adult stagesall live in the inner-nearshoremidwarer zone, I estimated adult-equivalent losses through post-flexion and for juveniles are approximatelyequal (Table 3). Therefore, we expect the maximum total adult- I equivalentloss to be approximatelytwice that through post-flexion. For theseother ,l taxa with entrappedjuveniles, this is not the case:planktonic stagesfound in the inner-nearshoremidwater depths are at greater risk than juveniles, sincejuveniles t move out of the inner-nearshoremidwater to adult habitats. Thus for theseta(a, we expectadult-equivalent loss for the juvenile to be less than that for the planktonic l stages. t Our estimate of relative adult-equivalentloss is less than O.'l.Vofor northern t anchovy. Most northern anchovy larvae (and presumablyjuveniles) are found offshoreof E-Block and are at low risk to entrapment. t SONGS also entrains the juvenile stage of viviparous perch (barred T surfperch, kelp perch, pile perch, rainbow seaperch,rubberlip seaperch,shiner perch, walleye surfperch,white seaperch). As with the juvenile stageof other ta: I In: -4ssesstngthe effectsof power-plant-inducedmortality on fish populatioru. t Pergamon,N.Y. W. Van Winkle, ed. pp. 196-226. l DeMartini, E. and UCSB Staff. 1987. The effectsof operationsof the San Onofre Nuclear Generating Station on fish. Report to the Marine Review il Committee,Inc. I ECOsystemsManagement Associates, Inc. 1988. Volume II-2: Disturbanceof the l Flow-Field by the Cooling Systemof SONGS. Draft Final Report 1.987. MRC t DocumentNo. D87-165. Eschmeyer,W. N., E. S. Herald and H. Hamman. 1983. A Field Guide to Pacffic t Coast Fishesof NorthAmeica. Houghton Mifflin Company,Boston. 336 pp. l I 39 I I I Goodyear, C. P. 1978. Entrainment impact estimatesusing the equivalent adult approach. U.S. Fish.Wildl. Serv.Off. Biol. Serv.,Rep.FWS/OBS-78/65, t Wash.,D.C. ! Hackney,P.A., T. A. McDonaugh,D. L. De Angelis,and M. E. Cochran. 1980. A t partial differential equation model of fish population dynamics and its application in impingement impact analysis. EPA 600/780-068and TVA T EDT-101.March L980,52p. t Horst, T. J. 1975. The assessmentof impact due to entrainmentof ichthyoplankton. n In: Fisheies and energt production: A symposium. Irxington Books, Lexington,Mass. S. B. Saila,ed. pp. 107-118. .T Horst, T. J. 1977. Use of the leslie matrix for assessingenvironmental impact with T an examplefor a fish population. Trans.Am. Fish. Soc.106: 253-257. I Jones,J. H. 1971.. General circulation and water characteristicsin the Southern t California Bight. SCCWRP,Los Angeles,Ca. 37 pp. I [.-ove,M. S., M. Sandu,J. Stein, K. T. Herbinson,R. H. More, M. Mullin and J. S. Stevens.1987. An analysisof fish diversionefficiency and survivorshipat the :l San Onofre Nuclear Generating Station Fish Return System. Prepared for SouthernCalifornia Edison. I t I 40 T I t tl MacCall,A.E., K. R. Parker,R. Leithiser,and B. Jessee.1983. Power plant impact T assessment:a simple fisheriesproduction model approach. U.S. Fish Bull. I 81: 613-619. I MRC. 1988a. Interim Technical Report 5. Fish l"arvae and Eggs. Report to the California CoastalCommission. t MRC. 1988b. Annotated Interim Report of the Marine Review Committee to the I California CoastalCommission. MRC. No. 88-054. I MRC. 1989. Final TechnicalReport C. Entrapment of Juvenile and Adult Fish at t, SONGS. Report to the California CoastalCommission. t MRC. 1989. Final TechnicalReport M. Bight-wideeffects on fish: Compensation. t Report to the California CoastalCommission. L Vaughan, D. C. 1981. An age structure model of yellow perch in western I-ake Erie. In: Quantitativepopulation dynamics. International Co-operative I PublishingHouse, Fairland, Md. D. G. Chapman and V. F. Gallucci, eds. pp. L89-2r6. l Vaughan,D. S., and S. B. Saila. 1976. A method for determining mortality rates t usingthe Lesliematrix. Trans.Am. Fish.Soc. 105: 380-383. t I t 47 T I I I t I I n ,t This pageintentionally left blank. il ,l I tr I tl I l I I T t I il' t t I I T 6.0 TABLESand FIGURES t T t I t I il t' I I T I T Table 1 I Common and scientific names. ,,I Common Name Scientific Name t Arrow goby Clevelandiaios Black croaker Cheilotremasatumum I Blenny(unid.) Hypsoblenniusspp. qu6L clingfish Gobiesoxrhessodon I Calif. corbina Mentichrhusundulatus Calif. grunion Leurestlrcstenuis I Calif. halibut Paralichthys califomicu s Cheekspotgoby Ilypnusgilbeni Pacificmackerel Scomberjaponicus I Diamond turbot Hypsopsettaguttulata Giant kelpfish Heterosticltusrostratus I Hornyheadturbot Pleuronichtlrys vertic alis Jacksmelt Atheinopsis califomiensis t Kelp and barred sandbass Paralabraxspp. Kelpfish (unid.) Gibbonsiatype a Northern anchovy Engraulismordax t Queenfish Seiphuspolirus Reef finspot Paraclinu s integripinnis ! Salema Xenistiuscalifomien sis Shadowgoby Quieulay-cauda I White croaker Genvonentuslineatus I il t Ir t 44 I I I Table 2 Ratios of mean densities for combinations of Blocks (AB/ABCD and ABCD/ABCDE) and the number (n) of cross-shelf surryeyswith occurrences. (Note the ratio of means does not change if suraeys with occurrences are included.) Yolksac and preflexion stages have been combined t (ys/preflexion). I JTryENILES ENTRAPPED AB/ ABCD/ I ABCD n ABCDE Black croaker eggs 0.068 0.834 I ys/preflexion 0.068 51 0.834 38 flexion 0.068 0.834 J post-flexion 0.408 5 1.000 2 I Calif. corbina eggs 0.1.19 0.931 a- ys/preflexion 0.119 47 0.931. LI flexion 0.191 T9 1.000 L3 I post-flexion 0.996 4 1.000 J Calif. grunion ys/preflexion 0A% 98 0.704 66 I flexion 0.3.,10 91. 0.7L9 64 post-flexion o.6N 88 0.867 OJ Jacksmelt ys/preflexion 0.46 88 0.915 58 t flexion 0.600 69 0972 45 post-flexion 0.494 49 0.990 34 I Kelp & barred eggs 0.025 0.720 sandbass ys/preflexion 0.025 67 0.720 40 flexion 0.003 32 0.5r.0 23 T post-flexion 0.065 3L 0.515 22 N. anchovy eggs 0.082 0.584 ys/preflexion 0.082 t4L 0.584 87 I flexion 0.097 LlE 0.687 94 post-flexion 0.L75 151. 0.823 91 Queenfish eggs 0.159 0.786 I ys/preflexion 0.159 IX 0.786 90 flexion 0.793 109 0.983 78 I post-flexion 0.953 r02 1.000 70 Salema eggs 0.063 0.708 ys/preflexion 0.063 32 0.708 t4 t flexion 0.011 19 0.7'x 9 post-flexion 0.158 14 0.489 6 White croaker eggs 0.ry 0.748 I ys/preflexion 0.I34 L23 0.748 82 flexion 0.348 96 0.996 68 I post-flexion 0.296 86 1.000 64 I 45 t Table 2. (Continued) I JTIVENILESNOT ENTRAPPED I ^B/ ABCD/ ABCD n ABCDE I Arrow goby ys/preflexion 0.580 65 1.000 45 flexion 0.982 90 r..000 54 post-flexion 0.916 r.33 1.000 84 I Blenny (unid.) ys/preflexion 0.093 L4L 0.686 93 I flexion o.0B 70 0.ffi 5L post-flexion 0.0L5 59 0.641 46 Calif. clingfish ys/preflexion 0.545 96 0.999 63 I flexion 0.758 57 1.000 38 post-flexion 0.253 33 1.000 18 I Calif. halibut eggs 0.059 0.774 ys/preflexion 0.059 723 0.774 81 flexion 0.013 45 0.676 30 I post-flexion 0.061 72 0.835 52 Cheekspotgoby ys/preflexion 0.729 r2r 0.888 70 flexion 0.878 105 1.000 55 I post-flexion 0.7M r22 1.000 7L Pacific mackerel eggs 0.L25 0.753 I ys/preflexion 0.r25 61. 0.753 3; flexion 0.005 30 0.594 23 post-flexion 0.002 23 0.725 18 I Diamondturbot eggs 0.383 0.846 ys/preflexion 0.383 5; 0.846 3; flexion 0.4L4 23 0.6L 2A I post-flexion 0.650 13 1.000 12 Giant kelpfish ys/preflexion 0.707 69 1.000 50 flexion 0.545 47 1.000 29 I post-flexion 0.949 )') 0.981 t4 Hornyhead eggs 0.029 0.61"4 I turbot ys/prefleion 0.029 LL; 0.614 73 flexion 0.m6 29 0.24L 24 post-flexion 0.037 28 0.258 23 I Kelpfish(unid.) ys/preflexion O.7LL 87 1..000 53 flexion 0.678 40 1.000 24 post-flexion 0.665 23 1.000 16 I t 46 I Table 2. (Continued) JTryENILESNOT ENTRAPPED ABI ABCD/ ABCD n ABCDE Reef finspot ys/preflexion 0.7t7 47 1.000 23 flexion 0.697 28 1.000 L2 post-flexion 0.,185 T9 1.000 8 Shadowgoby ys/preflexion 0.856 86 1.000 46 flexion 0.974 65 1.000 ?5 post-flexion 0.851 69 1.000 28 I Table3 I Relativeadult-equivalent loss (AEL), I - & through stage,accumulated to that stage. Estimated daily entrapment rate (from Table A3) is the number entrappedper day divided by the standing stock Yolksac and preflexion stageshave beencombined (ys/preflexion). We equateentrapment rates for eggsto thosefor ys/preflexion. I JTryENILES ENTRAPPED t Entrapment Duration AEL Rate t 1-& I Black croakerl eggs 6.028-05 2.5 A.0L5Vo ys/preflexion 6.02E-05 15.2 0.L06Vo flexion 4.3IE.M 6.0 0.%4% post-flexion 1.06E-03 v.0 3.897Vo Calif. corbinal eggs I.T1E-M 2.5 0.029Vo I ys/preflexion 1..r78-M 9.2 O.l37Vo flexion 2.02E-M 8.0 0.298Vo post-flexion 1.05E-03 3L.6 3.552Vo I Calif. grunionl'2 ys/preflexion 8.75E-M 1L.3 0.984% flexion 6.95E-04 LL.7 L.786Vo post-flexion 1.58E-03 L8.3 4.585% Jacksmeltl ys/preflexion 4.318-04 ?I.0 0.858% flexion 6.1.5E-04 18.0 L.950Vo post-flexion 5.16E-04 10.0 2.454Vo Kelp & barredl eggs 1.90E-05 2.5 0.ffi5Vo sand bass ys/preflexion r,.90E-05 7.7 0.0I9Vo flexion 2.11E-06 5.0 0.020Vo post-flexion 3.laE-05 18.3 0.084% N. anchoql eggs 2.458-07 2.5 < 0.0LVo ys/preflexion 2.458-07 24.L < O.OlVo flexion 3.42E-07 16.7 < 0.OLVo post-flexion 5.82E-07 6.7 < 0.L0% juvenile r.20E-07 255.0 < 0.10Vo Queenfish eggs L.328-M 2.5 0.033% ys/preflexion r.32E-M 18.0 0.n0% flexion 8.?3E-04 L2.0 L.250% post-flexion 1..01E-03 4.0 5.543% juvenile 2.73E-M 288.5 L2.695Vo Salemal eggs 4.758-05 2.5 0.0r2% ys/preflexion 4.758-05 10.0 0.059% flexion 8.,148-06 8.0 0.066% post-flexion 8.138-05 36.0 0.358% 48 I t Table3. (Continued) JTryENILESENTRAPPED I Entrapment Duration AEL I Rate t 1'Rc White croaker2 eggs r.768-04 2.5 0.0M% ys/preflexion r.76E-04 22.0 0.430Vo flexion 6.L2E-M 10.0 L.038% I post-flexion 5.22E-M 55.0 3.839% t juvenile 1.41E-04 n5.5 7.500Vo I JWENILES NOTENTRAPPED Entrapment Duration AEL I Rate t 1'Rc Arrowgobf ys/preflexion 3.64E-04 8.0 0.29lVo flexion 6.22E-44 10.0 0.909% I post-flexion 5.808-04 29.6 2.596% Blenny(u"id.) ys/preflexion 6.75E-05 8.6 0.O58Vo flexion 1..58E-05 29.3 0.L04Vo t post-flexion 1.06E-05 29.7 0.|%Vo Calif. clingfish ys/preflexion 5.748-M t2.o 0.686% I flexion 8.00E-04 8.0 r.320% post-flexion 2.6TE.M 4.0 I.425Vo Calif. halibut eggs 4.85E-05 2.5 0.0I2Vo I ys/preflexion 4.858-05 L4.6 0.O83Vo flexion 9.50E-06 8.3 0.wr% I post-flexion 5.38E-05 4.2 0.Ll3Vo Cheekspotgoby ys/prefledon 6.83E-04 8.0 0.545% flexion 9.nE-04 4.0 0.9L3Vo I post-flexion 7.878-04 n.6 3.WVo Pacific mackerel eggs 9.92E-05 ?\ 0.025% ys/preflexion 9.928-05 4.9 0.073% I flexion 3.L78-M 4.4 0.075Vo post-flexion 1.068-06 2r.2 0.077% t Diamondturbot eggs 3.428-04 2.5 0.085Vo ys/preflexion 3.42E-U 9.2 0.399% flexion 2.898-04 6.0 0.572Vo I post-flexion 6.86E-04 22.0 2.MIVo I I 49 Table 3. (Continued) JT'VENILESNOT ENTRAPPED Entrapment Duration AEL Rate t 1-R. Giant kelpfish ys/preflexion 7.4r.E-M 4.1 0.305Vo flexion 5.75E-M 5.4 0.6L4% post-flexion 9.83E-04 6.2 6.876Vo Hornyhead eggs 1.90E-05 2.5 0.0A5Vo turbot ys/preflexion 1.908-05 35.0 0.07L% flexion 1.06E-06 25.0 0.074% post-flexion 1.06E-05 45.0 O.L22Vo Kelpfish(unid.) ys/preflexion 7.50E-04 8.0 0.598Vo fledon 7.16E-04 6.0 t.024% post-flexion 7.02E-04 58.0 4.973Vo Reef finspot ys/preflexion 7.57E-0/r 6.0 0.43Vo flexion 7.%E-0/i 4.0 0.746% post-flexion 5,LZE-M 42.0 2.857% Shadowgoby ys/preflexion 9.038-04 8.0 0.7?r% flexion 1.03E-03 0.0 0.720Vo post-flexion 8.988-04 1.6.0 2.L36Vo Juvenile stage inestimabledue to lack of data on adult stock size. See DISCUSSION, section 4.1..1,, paragraph3. Adjustedfor SONGS'effect(see Table A.1). 50 I I Table 4 I Estimated adult-equivalent loss through last stage entrapped. I TAXA WHOSEJTIVENILES ARE ENTRAPPED I Common name Adult-EauivalentLoss Black croakert (3.8eVo) I Calif. corbinal (3.ssvo) Calif. grrrniell'2 (a.59Vo) Jacksmeltl (z.a1Vo) I Kelp and barred sand bassl (o.o8Vo) Northern anchovf'3 <0.L0Vo Queenfish3, L2.7IVo Salemal (0.%%) I White croaker2,3 7.50Vo I TAXA WHOSEJT]VENILES ARE NOT ENTRAPPED I Commonname Adult-EcuivalentLoss Arrow gobf 2.60Vo I Blenny(unid.) 0.I4Vo Calif. clingfish L.43Vo Calif. halibut 0.[% Cheekspotgoby 3.04Vo I Pacificmackerel 0.08% Diam616turbot 2.M% Giant kelpfish 6.$Vo t Hornyheadturbot 0.LZVo Kelpfish (unid.) 4.97Vc Reef finspot 2.86Vo I Shadowgoby 2.I4Vo I Relative loss through juvenile stage inestimable. Loss is estimated only through post-flexion. See DISCUSSION,section 4.1.L, paragraph 3. I Entrapmentrate adjustedfor SONGS'effect on density. Changesin density: arrow goby(-40Vo), California grrrnion(+170%), northern anchovy(-77Vo), and white croaker(+67Vo). I Lossestimated through the juvenilestage. I I 51 Table 5 Potential losses to the adult standing stock in biomass and number for queenfish and white croaker. Adult standing stock estimated in Appendix B, Tables 8.6 and 8.7. Adult-equivalent toss (AEL) presented in Table 4. High, middle and low estimates are based on high, middle and lol estimates of juvenile entrapment rate given in Appendix D. ESTIMATED ADT]LTSTANDING STOCK Biomass (MT) Numbers of Fish Queenfish 4,341 1.40E+08 White croaker 5263 5.50E+07 LOSSTO STANDINGSTOCK AEL Biomass (MT) Numbers of Fish Queenfsh 12.7Vo 551 1.8E+07 White croaker 7.5Vo 394 4.1E+06 52 t I Table 6 The number of L'year-old equivalents killed by SONGS' entrapment of eggs, larvae and juveniles equals the number of 1-year olds that recruit to the length of the nshoreline equivalentn (see section 4-1) in kilometers. We expect SONGS' effect to be more widespread that this. Values assume no I compensation for preadults. I TAXA WHOSE .ITTVENILES ARE ENTRAPPED I Common name Kilometers Black croaker >19 Calif. corbina >19 Calif. grunion >23 Jacksmelt >12 Kelp and barred sand bass <1 Northern anchovy <1 I Queenfish g Salema >2 I White croaker 38 I TAXA WHOSE JTJVENILESARE NOT ENTRAPPED I Commonname Kilometers Arrow goby L3 Blenny(unid.) <1, Calif. clingfish 7 I Calif. halibut <1 Cheekspotgoby 15 Pacificmackerel <1. I Diamond turbot 10 Giant kelpfish v Hornyheadturbot <1 t Kelpfish (unid.) 25 Reef finspot t4 I Shadowgoby 11 I I t I 53 This pageintentionally left blank. DEPTH(m) oOOOOOOO N|f)vlr)(olr.- E x rc trj E, o U' c L o sl' UJ () z F A tc) a L o OJ v, = i5 'oro c o (utn N x. tlt o .= c ; o o Figure1: Cross-shelfblocks at lmpact and Control sites, and their relationshipto intakesand diffusers. This pageintentionally left blank. APPENDICES This pageintentionally left blank. I t APPENDIX A I ESTIMATING ENTRAPMENT RATE FOR PI,ANKTONIC STAGES I We estimateentrapment rate by stageby dividing (1) intake loss (the number I entrappedper day) by (2) the standingstock in the southern California Bight. In Sections 4.L through A.4 we discuss procedures for collecting data, and for I estimatingintake loss (L), bight-wide standingstock (S), and entrapment rate (E). I We discussthe major assumptionsunderlying these methods in SectionA.5. I A.1 Data Collection I From t978 through 1986, Marine Ecological Consultants Inc. (MEC) I collecteddata on the densityof eggsand larvae of fish at two sitesin the vicinity of SONGS. The two siteslie approximately1 - 3 km (Impact) and 18.5km (Control) I downcoastfrom SONGS. Each site was divided into five cross-shelfblocks (A-, B-, C-, D-, and E-Blocks), and each block into three depth zones(neuston, midwater, T and epibenthos),resulting in 15 block/stratum combinations(see Figure f. in main report). MEC defined neuston as the top 0.16 cm of the water column and I epibenthosas the bottom 0.5 m. Seethe MRC (1988a)study on ichthyoplanktonfor I a detailed descriptionof samplinglocations and methods. I In 1.978,only the Impact site was sampled. From 1979through 1986both sites were sampled,usually on consecutivedays. In the following we refer to all I cross-shelftransects taken previous to July 1983 as preoperational,and all taken I after June 1983 as operational. Thus the preoperational period includes samples t A-1 t taken at Impact only in 1978. We divide samplingdates into preoperational and operationalperiods because SONGS' operation may haveaffected the abundanceof sometaxa at the Impact site in the operationalperiod. 4.2 Intake Loss We use the densities in A- and B-Blocks (which we refer to as the "AB density") to estimate intake loss, since the intake risers sit at approximately the boundaryof A- and B-Blocks. SONGS draws in water from both these blocks (ECOsystems1985). SONGS' operation may have affectedthe densityof some tuia at the Impact site. We use the relative percent change (between Impact and Control from preoperationalto operational periods), as estimatedby the MRC (1988a),to estimate intake loss for affected taxa. We discussthe implications of adjusting intake loss by relative percent change in Section A.5, Major Assumptions in EstimatingEntrapment Rate. Az.L Intake Inss for Taxa Not Alfectedby SONGS We estimate intake loss (L) by multiplying the mean density in A- and B- Blockstimes the meanintake volume: L=AB*Volin6L". AB is the averagedensity over sitesand periods: AB = (1/N)x(ab)xr A-2 I I where abi;t is an averagedensity, weighted by cross-sectionalarea of strata, I for each i survey,at j sites (Impact and Control) for k periods (preoperationaland operational). This gives an averagedensity in A- and B-Blocks. N is the total t number of cross-shelftransects sampled in the preoperational and operational I periods. I During the operationalperiod (mid-1983through 1986) SONGS' Units 2 and 3 averaged75Vo pumping capaciry,or six out of eight circulating pumps per day I (MRC 1988b). Each pump takesin approximately1.13 lff m3fday. Hence,for an averageof six pumps,Voli,,1uL" computes to 6.8 106rfi/day. We assumethat SONGS I will continue to intake water at this rate. I 4.22 lntake Loss for Taxa Alfected bv SONGS I SONGS'operationmay have changed the densityof sometaxa at the Impact I site relative to the Control site (MRC 1988a). Significantchanges in four taxa (type I I error < 0.05) were found. Shadow goby (Clevelandiarbs) and northern anchovy (Engraulis mordm) decreased at Impact relative to Control. White croaker I (Gerryonemuslineatus) and California grunion (Leuresthestenuis) increased. We I presentsignificance levels and estimatesof percentrelative changein Table A.1. We adjustthe densityat the Impact site,which is usedto estimateintake loss, I accordingto the estimatedpercent changesgiven in Table A.1. To estimateintake T loss we adjust the AB density (excludingthe operational period) to what it would have been had it been affected by SONGS' operation, accordingto the following I procedure: t A-3 t AIi' = WI*AB" + F*(l-W1)*AB"' Wr is the number of cross-shelftransects at Impact in the operationalperiod divided by the number of cross-shelftransects for both sites and both periods (N). AR" is the mean densityat Impact during the operationalperiod only. F is the adjustmentfactor for relative percent change. F = 1 + P, where P is the decimal equivalentof percentchange in Table A.1. AB"' is the meandensity when Impact is excludedduring the operationalperiod. F effectivelyadjusts the AB'/ , densityto what it would have been had it been affected by SONGS' operation. [Note we achieved similar estimatesof AB' by merely adjusting the mean density for all cross-shelftransects excluding Impact in the operationalperiod, F*AB' ' '.] Intake lossis then L' = AI|'*Vol;n1"L". A.3 Standing Stock in the Bight We estimate planktonic standing stock in the Bight by multiplying the number of propagules in a meter-wide strip of A- through E-Block times the number of meter-widestrips in the Bight (500,000). Again, we define the Bight as extendingfrom Cabo Colnet, Baja California, to Point Conception. Examination of A- through E-Block densities,as presentedin RESULTS, suggeststhat the eggsand larvaeof mosttaxa under study do not extendbeyond E-Block. BecauseSONGS may have affected A- through E-Block densities for the same ta.naconsidered in Section A.2.2, we compute standing stock for ta,xanot A-4 T I affected and taxa affected separately. Becausemost eggs and larvae of northern I anchory are found offshore of the nearshore zone sampled by the MRC, we l estimatestanding stock for this taxon separatelyin SectionA.3.3. I In the following section,all densitiesare in numbersper meter-widestrip of the variouscross-shelf blocks. I I .d3.1 Standing Stockfor Taxa Not Alfectedby SONGS I E-Block samples from the operational period were not analyzedin the laboratory. Consequently,we have only A- through D-Block samples for both I preoperationaland operationalperiods. We estimateA- through E-Block densities (ABCDE) as follows: t ABCDE = ABCD - (ABCDEe."oo/ABCDp*op), where ABCD is the mean density in A- through D-Blocks for all cross-shelf I transectsand (ABCDEp,"op/ABCDp*op) is the estimatedratio of mean densitiesin I the preoperationalperiod only. I ABCD = (1/N) ) (abcd)1r,where abcd is the densityfor each i survey,at j sites (Impact and Control) for k periods (preoperationaland operational), and N is the total numberof cross-shelftransects. Where ABCDE is the number per meter-wide cross-shelfstrip, standing stock(S) is S=ABCDE*500,000 sincethere are 500,000meter-wide strips in the Bight. A-5 I .d3.2 Standing Stockfor Taxa Alfectedby SONGS I I SONGS may have affected the ABCDE density of the four ta:ra listed in Table A.1. Thus, ABCDE densities as computed in Section A.3.1 yield t underestimatesof standingstock (and overestimatesof entrapmentrate and adult- equivalent loss) for taxa which decreasedin density at Impact in the operational I period (arrow goby and northern anchovy). Conversely, underestimates of entrapmentrate and adult-equivalentloss would result for ta:rawhich increasedin I density(California grunion and white croaker). I For taxa that may have been affected by SONGS' operation, we adjust for I SONGS'effect at Impact in the operationalperiod as follows: ABCDE' = G*Wr*ABCDE" + (1-W1)*ABCDE"' I G is the factor that adjustsABCDE density(in number per meter-widestrip) T to what it would have been at Impact in the operational period, had it not been affectedby SONGS. G = 1/(1+P), where P is the decimalequivalent of percent changein Table A.1. Wr is the number of cross-shelftransects at Impact in the operationalperiod dividedby the number of cross-shelftransects at both sitesand both periods (N). ABCDE" is the mean cross-shelfdensity for Impact in the operationalperiod. ABCDE"' is the mean densityat all cross-shelftransects exceptImpact in the operationalperiod. WhereABCDE' Standingstock (S') is S'=ABCDE'*500,000 sincethere are 500,000 meter-wide strips in the Bight. A-6 T I A.3.3 StandingStock of NorthernAnchorT I Since most eggs and larvae of northern anchovyare found offshore of E- I Block, we cannot estimate standing stocks of planktonic stagesfrom the MRC's I data. We use publisheddata (Picquelleand Stauffer 1985)on daily eggproduction I and instantaneousmortality rates (Smith 1985) to estimate an average standing I stockof planktonicstages. Using thesemortality rates,we computethe numberof propagulessurviving on successivedays from the number of eggsspawned; we add I the number of propagules over the duration (days) of each planktonic stage to I estimatestanding stock. Theseestimates are presentedin Table A2. We find that our estimatesof standingstock by stage are very sensitiveto t mortality rates. Changesof 25Voin mortality rates result in an order of magnitude I changein estimatesof standingstock. We use theseestimates of standingstock only to approximateentrapment rate (and ultimately loss). I adult-equivalent I A.4 EntrapmentRate I For taxa not affectedby SONGS,entrapment rate (E) is E = L/S. I For ta,raaffected by SONGS,entrapment rate (E) is I E'=L'/S' I T A-7 T I I Table A.3 showsestimates of entrapment rates. Note that for some tora, eggsare not entrapped. I A.5 Major Assumptions in Estimating Entrapment Rate I I A.5.1 using Impact and control Data for Taxa Not Affectedby soNcs T Intake loss: For computingintake loss (A.2.1),we assume1) densityat the Impact site equalsthe densitywithdrawn , and2) averagecontemporaneous densities I at Impact and Control sitesare equal. t Since the intake risers sit near the boundary of A- and B-Blocks and since I intake waters come from both A- and B-Blocks, the first assumptionis probably safelymade. However, it should be noted that the proportion of water withdrawn t from either A- or B-block may vary with oceanographicconditions. Furthermore, someB-Block samplesare taken as much as 3 km southof the intake risers. I t Evidence indicates that the second assumption,equal mean densities at Impact and Control, is also safe. We reviewedMEC's data for the preoperational I period. We find no consistentdifferences in A- and B-Block densitiesat Impact and Control sites. (Note, the MRC's (1988a)published statistical comparisons, BACIP, I are made on cross-shelfestimates of densityand not just A- and B- Blocks.) We did not look at the data taken in the operationalperiod, becausewe wanted to rule out t anypossible influence of SONGSin our analysis. I I A-8 I I I l Standingstock: Estimatesof standingstock (A.3.1) assume that the average I density at Impact and Control equalsthe averagedensity in the Bight. Review of data collected by the I-os Angeles County Museum (made available to us through t Southern California Edison) at 20 locations in the Bight shows that average I densitiesat Impact and Control are within the limits of densitiesfound elsewherein the Bight. The Museum data are not precise enough to quantitatively relate I densitiesnear SONGS to the rest of the Bight for the purposeof computingbight- I wide standingstock. Using the Museum data, I-avenberget al. (1986) show some evidencefor I consistentdifferences in the mean densitiesof some taxa benveenlocations in the t Bight; they show that densitiesof planktonic stagesmay be higher near habitats of spawningadults. But again, we find no appropriate way to quantitatively relate I densitiesat SONGSto densitiesin other areasof the Bight. I A,5.2 Interpreting and Estimating SONGS'Effect t As documented in the Technical Appendix on Ichthyoplankton, SONGS' I operation could have brought about changesin densityof planktonic stagesfor the following reasons: Decreasescould haveresulted from 1) intake lossfrom transiting I SONGS (that is, larvae were removed by SONGS and the plankton free discharge waters diluted the density at the Impact site), 2) avoidanceof the Impact area, 3) I higher mortality rates in the area of SONGS due to increasedturbidity, turbulence I from diffuserjets, or increasedabundance of planktivorousfish and/or zooplankton, and 4) distributional shifts in densitydue to movementsof water causedby SONGS' intakes and diffusers. Increasescould have resulted from 1) increasedsurvival, 2) A-9 T I attraction due to increasedfood availability,and 3) as with decreases,distributional shifts in density due to movements of water caused by SONGS' intakes and I diffusers. The MRC (1988a)was unable to determinea way which could explain the magnitudeof such decreasesand increases.Further, how SONGS' effect could be I taxon-specific(causing both increasesin some taxa and decreasesin others) is problematic. I t There are three ways to interpret these changes at Impact (relative to Control). I First interpretation: Decreasesand increases,while statisticallysignificant, T result from natural changesin densityand not from SONGS' operation; the relative T changesin abundancebetween Impact and Control are within the range of changes expected over time. This hypothesisis supported by two arguments: (1) The t majority of preoperationalsamples were taken in 1980. This brief period may not provide an adequate baseline (i.e., without SONGS) of Impact and Control I densities. We effectively have only one sample (one spawning season)for the preoperational period. (2) The affected taxa may not be appropriate for testing I SONGS' effects. The larvae of three taxa come from eggs not produced near I SONGS: the eggsof arrow goby and California grunion are demersal,and eggsof the goby are spawnedin bays. Northern anchovyspawn planktonic eggsprimarily offshore of E-Block. These then are not ideal tw A-10 t I period (May 1980)to the last year of the operationalperiod (1986). Consequently, I the data used for analysismay not represent"average" conditions for white croaker. The BACIP test resultsfor white croaker are somewhatambiguous. While evidence t indicates white croaker larvae increased at the Impact site, we point out that, I becauseof the nature of white croaker data, the interpretation of the results for white croaker are disputable. (SeeBarnett 1987). t If these changesare not a result of SONGS' operation,and probably not I long-term, then in computing intake loss we need to incorporate data from both periods (preoperational and operational) and both sites (Impact and Control) l equally. I Secondinterpretation: Decreaseddensity in larvae resultsfrom mortality I due to turbulenceof diffuserjets (and/or other reasonslike increaseddensity of planktivores). L,owerAB densitiesat the Impact site decreaseestimates of intake I loss (and adult-equivalentloss). Increaseddensity resulting from increasedsurvival t (perhapsfrom increasedavailability of food) near SONGS yields a similarly false result. High AB density increasesestimates of intake loss (and adult-equivalent I loss). I In order to accuratelyestimate the total effect of SONGS'operation under this secondinterpretation, we would need to quanti$/ increasesand decreasesover I the spatialextent of SONGS'effect. We lack sufficientdata to do this. I Third interpretati,pn: Decreaseddensity near SONGSresults from dilution I (larvae are filtered out of the Impact area by the plant) and,for redistribution of I A- 11 T I I different plankton densities(perhaps from inducedcross-shelf shifts in densities) due to water movementscaused by intakesand diffusers. Thus,SONGS decreases I the AB density, and intake lossis less. Increaseddensity near SONGSresults from redistribution of plankton by water movements caused by the intakes, andfor I attraction due to increasedfood availability. Thus SONGS increasesthe densityof I larvaenear the intakesand intake lossincreases. l With theseinterpretations in mind we make the following two decisions: 1) Observedstatistical changesresult from SONGS' operation. This decision is I consistent with other MRC reports in which we assume that all statistically significantBACIP changesare causedby SONGS,unless there is strong evidenceto t the contrary. 2) We adjust intake loss accordingto the relative reductionsreported I (MRC 1988a). Thus, accordingto the secondinterpretation, we could be falsely L) underestimatingadult-equivalent loss for taxawhich decreaseat Impact (arrow goby I and northern anchovy)and 2) overestimatingadult-equivalent loss for taxa which increaseat Impact (California grunion and white croaker). [Note in RESULTS we I also present estimatesof adult-equivalentloss computedunder the assumptionthat T relative changesat Impact in the operationalperiod are random and not causedby SONGS, the first interpretation. In this case,factors F and G (A.2.2 and A.3.2) I equalone.] I A.5.3 Using Impact Data for AffectedTaxa t Intake loss: We assumethat larval densitiesat Impact, as affected by I SONGS' operation,equal that at intakes(A.2.2). Sincewe assumethat SONGS' I A- T2 T t t t operationsaltered densitynear the intakes,we use the data taken at the Impact site I to estimateloss since this was the closestMRC samplingstation. I Intakes are rarely under the direct influence of the plume. Therefore, I acceptanceof this assumptionfurther implies that SONGS'effect is persistentand is associatedwith neither the immediately dischargedplume nor direction of current. I We have no data on which to evaluatethese implications. T Standingstock: In estimatingthe standingstock of affectedtzura (A.3.2), we assumeSONGS affectsdensities equally in the cross-shelf(A- through E-Blocks). l The relative percent changesshown in Table A.1 were for A- through D-Blocks. t We do not know if SONGS' effect extendsto E-Block, sinceE-Block sampleswere not t analyzedfor the operationalperiod. We discussthe implicationsof this in A.5.5. As a check on an equal SONGS' effect in the cross-shelf,we computed l standingstock estimatesof affected taxa by using the mean density over all cross- I shelf transects,except Impact for the operationalperiod. From A.3.2, ABCDE' = ABCDE"'. Here, we effectivelyeliminate the needto adjustoperational surveys I taken at the Impact site by not consideringthem. Estimated entrapment rates I computedin thesetwo waysare similar (within plus or minus 1,5Vo). T A.5.4 Means Over Time I In computingintake loss and standingstock, we estimatemean densitiesover time (A2 and A.3). That is, we compute a ratio of means [(mean entrapped) / I (mean standingstock)] rather than mean of ratios by survey[mean (entrapped/ I A- 13 I I t standingstock)]. This ratio of meansstatistically weights by abundance,surveys with greater abundancecount more in estimatingentrapment rate and adult-equivalent I loss. Since SONGS kills more larvae during times of high abundance (and consequentlyhas its greatesteffect on adult equivalents),we feel this assumptionis I appropriate.Sampling dates are shownin MRC (1988a). I A.5.5 No Standing Stock Beyond E-Block T In estimating standingstock (A.3), we assumethat planktonic stagesdo not t extend beyond E-Block (approximately 7 km offshore). For some ta: For taxathat do occurin non-trivialnumbers beyond E-Block our estimateof t stock size is too low and we overestimateentrapment rate and adult-equivalentloss. I Our analysesdemonstrate that taxawhose planktonic stagesextend beyond E-Block have low estimatesof adult-equivalentloss, even when we (wrongly and knowingly) I A-14 t I I I assumezero densitybeyond E-Block. In RESULTS we discuss,for each taxon, the I effect of the assumptionof zero densitybeyond E-Block by ta: T A-5.6 LossIs ProportionateAcross All DepthStrata I In estimatingintake loss,we assumethat SONGS' samplesvertically zoned I organisms(those with relatively high densitiesin the neustonand epibenthos)in the I sameproportions as the watersthey live in. ECOsystems(1985) concludes that Units 2 and 3 intakeswill excludethin I layersnear the surfaceand seabedonly on rare occasions. I Sometaxa stratify vertically, especiallyin the flexion and post-flexionstages. I The meansby which theselater stagesaccomplish natural stratification may depend on buoyancyand swimming speed,as well as other factors for maintaining vertical positionin the water column. Thesefactors, plus responsetime, may determinea propagule'sability to remain in the top and bottom 1,/4-to lf2- meter of the water column,and thus avoid being entrappedby SONGS. The highest densities of flexion and post-flexion stagesof some taxa are found near the surfaceand bottom. For instance,Jahn and Lavenberg(1986) found mostpost-flexion queenfish larvae within 0.5m of the bottom. Using MRC data,we find the sameresult, that approximately80Vo of post-flexionqueenfish occur within the epibenthos. If individuals living in the (relatively thin) top and bottom layers are not entrapped by SONGS, we will overestimateintake loss (and ultimately adult-equivalentloss). Hence,our estimatespresent a worstcase scenario. A- 15 we discussthe effect of swimmingspeed on entrapmentin Appendix D. 4.5.7 Equal Effect AcrossAll Stages Estimatedpercent changescaused by SONGSshown in Table A.1 are for all larval stagescombined. We apply this percent changefor eachstage separately, and therefore assumethat the percent relative changefor each stageequals that for all stagescombined. Becauseof high variance in density estimates(due in part to frequent zero occurrences),percent relative changeis difficult to test and estimate separatelyby stage. From examining survey-by-surveydata, we conclude that percent change cannot be estimatedwith sufficient precisionby stagefor the pulpose of estimating intake lossfor affectedtaxa. A.5.8 PrecisionofAdult-Equivalent Loss Estimating the precisionof entrapmentrate and ultimately adult-equivalent loss is not feasible becausemany of the estimateson which entrapment rate is estimatedare based on a single observation,natural history, andfor judgment. Precisionis very likely low. A- 16 I T REFERENCES l Barnett, A. M. 1987. MEC Biological Project San Onofre Nuclear Generating t Station Monitoring Studies on Ichthyoplankton and Zooplankton. Final I Report.MRC DocumentNo. D87-085. ECOsystemsManagement Associates, Inc. 1985. SONGSPhysical and Chemical I Oceanography:Intake Selectivity;1984-85 Final Report to the MRC. Vol II. I Jahn, A. E. and R. J. L,avenberg. 1986. Fine scale distribution of nearshore, I suprabenthicfish larvae. Mar. Ecol. Prog.Ser. 3i.: 223-23t. t Lavenberg,J. L., G. E. McGowen,A. E. Jahn,J. H. Petersen,and T. C. Sciarrotta. t 1986.CaICOFI Rep., Vol XXVII:53-64. t MRC. 1988a. Interim Technical Report 5. Fish larvae and eggs. Report to the t California CoastalCommission: MRC. 1988b. Annotated Interim Report of the Marine Review Committee to the l California Coastal Commission. MRC Document No. 88-05,4' Report I submittedto the California CoastalCommission. T I I l A- 17 I I t Picquelle,S., and G. Stauffer. 1985. Parameterestimation for an egg production method of northern anchovybiomass assessment.In: An eggproduction T methodfor estimatingspawntng biomass of pelagicfah: applicationsto northem anchovy,Engraulis mordax. U.S. Dept. Commerce, NOAA Tech. Rept. l NMFS 36. R.I-asker,ed. pp. 7-15. I Smith, P. E. 1985. Year-classstrength and survival of O-group clupeoids. Can J. I Fish-Aquat. Sci. 42: 69 &82. T I I I A- 18 I T TABLE A.1. BACIP test results for the relative change between Impact and Control sites from I preoperational to operational periods, and estimated percent relative change for taxa with type I error \ 0.05 (from the Interim Technical Report 5. Fish larve and I eggs,MRC 1988). I I I P>T 7o CnencB Arrow goby 0.006 -4OVo I Calif. grunion 0.001 +L70Vo Northern anchovyl <0.050 -TlVo t White croaker 0.049 +67Vo I 1 Northern anchovy was tested separately for surveys of high and low abundance. I Percent change listed is for all surveyscombined. I I A- 19 TABLE A.2. Estimated standing ,s"tock of planktonic stages of northern anchovy based on a mean daily egg production of 15x1.0^o eggs/day, and instantaneous daily mortality rates of 025,0.16, and 0.05 for ages 0-7, 8-19, and greater than 20 days, respectively. Daily egg production is the mean from 1980 to 1984 (Picquelle and Stauffer 1985). Mortality rates are from Smith (1985). Durations of stages given in Table 82. DAY DaY STAGE BEGIN}uNG ENDING STANDING STocx yslpreflexion 2.5 ?6.6 3.88+1:! flexion 26.6 43.3 2.8E+t2 post-flexion 43.3 1.10.0 2.48+t2 A-20 I I TABLE A.3. Estimated entrapment rate (number entrapped per day divided by standing stock) by stage. Yolksac and preflexion stages have been combined (ys/pretlexion). We I equate entrapment rates ofeggs to those ofys/preflexion. I TAXA WHOSEJTIVENILES ARE ENTRAPPED ENTRAPMENTfTATE I Black croaker eggs 6.02E-05 ys/preflexion 6.02E-05 flexion 4.3LE-04 t post-flexion 1.06E-03 Calif. corbina eggs L.L7E-04 I ys/preflexion L.L7E-04 flexion 2.02E-M post-flexion 1.05E-03 I Calif. grunionl ys/preflexion 8.75E-04 flexion 6.958-04 I post-flexion 1.58E-03 Jacksmelt ys/prefledon 4.318-04 flexion 6.15E-04 I post-flexion 5.16E-04 Kelp & barred eggs 1.90E-05 sandbass ys/preflexion 1.908-05 I flexion 2.ILE.M post-flexion 3.4tlE-05 N. anchovyl eggs 2.458-07 I ys/preflexion 2.458-W flexion 3.42E-07 t post-flexion 5.82E-07 Queenfish eggs L.328-M ys/preflexion r.328-04 I flexion 8.238-04 post-flexion 1.018-03 Salema eggs 4.758-05 I ys/preflexion 4.758-05 flexion 8.448-06 I post-flexion 8.1.3E-05 White croakerr eggs L.768-M ys/preflexion r.76E-04 flexion 6.tzE-0/ I post-flexion 5.22E-04 l A-21 I I Table A.3. (Continued) t TAXAWHOSE JT.]VENILESARE NOT ENTRAPPED ENTTRAPMET{RATE I Arrow gobyl ys/preflexion 3.6TE-04 flexion 6.22E-04 I post-flexion 5.80E-04 Blenny(unid.) ys/preflexion 6.758-05 t flexion 1..588-05 post-flexion 1..06E-05 Calif. clingfish ys/preflexion 5.748-M t flexion 8.00E-04 post-flexion 2.678-04 I Calif. halibut eggs 4.85E-05 ys/preflexion 4.85E-05 flexion 9.508-06 post-flexion 5.388-05 T Cheekspotgoby ys/preflexion 6.83E-04 fledon 9.278-04 I post-flexion 7.878-04 Pacific mackerel eggs 9.928-05 ys/preflexion 9.92E-05 flexion 3.ITE-06 post-flexion 1.068-06 Dia-ond turbot eggs 3.428-M ys/preflexion 3.42E-04 flexion 2.89E-04 post-flexion 6.85E-04 Giant kelpfish ys/preflexion 7.ME-04 flexion 5.758-M post-flexion 9.838-04 Hornyhead eggs 1.90E-05 turbot ys/preflexion 1.90E-05 flexion 1.06E-06 post-flexion 1".06E-05 Kelpfish(unid.) ys/preflexion 7.50E-04 flexion 7.16F-0/. post-flexion 7.028-M Reef finspot ys/preflexion 7.5TE-04 flexion 7.%E-M post-llexion 5.I28-M A- 22 TableA.3. (Continued) TAXAWHOSE JWENILES ARE NOT ENTRAPPED ENTRAPMET{ITATE Shadow goby ys/preflexion 9.03E-04 flexion 1.038-03 post-flexion 8.98E-04 1 Adjusted for SONGS' effect on density (see Table A.1): arrow goby (4AV), California grunion (+l70Vo), northern anchovy(n%), andwhite croaker(+67Vo). A-23 t I I This pageintentionally left blank. t I APPENDIX B I ESTTMATINGADULT STOCK SIZE T We cannot estimatedaily entrapmentrates for juveniles becausewe do not I have data on density of juveniles. Consequently,we estimate anaveragejuvenile entrapmentrate accordingto an exponentialrate of decreasefrom the entrapment t rate of post-flexionlarvae to the entrapmentrate of early adults (Appendix D). We I estimatethe entrapmentrate of early adults by dividing the estimateddaily inplant loss of early adults by the estimatedbight-wide standing stock of early adults. In this I appendix,we estimatethe standingstock of adults. In Appendix C, we 1) partition standing stock and daily inplant loss into their early adult componentsand 2) t estimatedaily entrapmentrates of early adultsby taking the quotient of thesetwo. I Adult stock sizes estimated in this appendix are also used to estimate I potentiallosses in numbersand biomass (section 3.3). I B.1 Introduction t We obtain estimatesof the sizes of adult stocks for three ta,xa,queenfish, I white croaker and northern anchory. We use a modification of the "EggProduction Method"(EPM) (Parker 1980,1985; Picquelle and Stauffer1985) to estimatebight- I wide abundanceof queenfishand white croaker. Publishedestimates of stock size, T mostlybased on the EPM, are usedfor the northern anchovy. t I B-1 T Estimatesof adult abundancehave two importantuses: (1) the fraction of total adults that fall into the young adult categoryis necessaryas the denominator (S) used in calculatingthe entrapmentratio (E) of young adults (Appendix C). (2) Adult stock size is necessaryto convert relative losses(1 - R.) to numbersof adult equivalentslost. The EPM provides estimatesof the size of adult populationsbased on measuresof the production of spawnedeggs and the fecundity of adult female fish. Egg production is calculated from standing stock abundanceof eggsin plankton samples. Female fecundity is characterizedin terms of seasonalegg output per averagefemale (i.e., this is batch fecundity times the number of spawningsper seasonfor taxa that spawnmore than once a year). Using EPM we estimate stock size by taking the ratio of daily eggproduction to the expectednumber of eggsper individual in the stock. To calculatethis expectednumber we need to estimatethe fraction of the stock that are females,the fraction of thesefemales which will spawn per day, and the average batch fecundity of these spawning females. These calculationscan be expressedas follows: A = P/F*f*R (Parker 1980), EOU (1) where A = adult standing stock abundance P = daily egg production ofthe stock, F = ?Verrge batch fecundity, f = female spawning fraction (daily), and R = adult female fraction of stock (females/ adults) on a weight basis. B-2 t I To estimatethe biomassof the adult stock (B), F is expressedas mean l weight-specificfecundity (number of eggs/g)(Picquelle and Stauffer 1985),and R is the fraction that adult femalescontribute to total adult biomass. For a numerical I stock estimate (N), F is expressedas the number of eggsper batch produced by a I female of averagebody weight, and R is the fraction that adult femalescontribute to the total numbersof t spawningfish of both sexes. t 8.2 Queenfish and White Croaker: t Egg Abundance and Production t B.2.1 Egg Abundance Sincequeenfish and white croaker eggscannot be identified, we estimateegg I abundanceindirectly using the numbersof unidentified, small pelagic eggspresent I in samples. This is different than the regressionmethod used when eggs of the target taxa are identifiabls, e.8., the approach used by NMFS personnel for the I northern anchovy (I-o 1985). (Only the anchovy,among local taxa, has readily identifiable eggs.) We estimate the standing stock of queenfish eggs as follows: t Total unidentified (i.e., non-anchovy)eggs present on MEC cruisesmade off San I Onofre during the queenfish spawningseason are multiplied by the fraction that queenfishyolksac and preflexion larvae contributedto total (including unidentified) I yolksac and preflexion larvae present on these cruises. That is, assumingequal I survivorshipof egg,yolksac and preflexion larvaefor all ta,ra, t QFSHEGGS = TOTEGGS * QFSHFRAC, EOU (2) t B-3 t where QFSHFRAC = (queenfish yolksacs + preflexions) divided by (total yolksacs + preflexions). The queenfish spawningseason extends from February or March through July or August, depending on year (DeMartini and Fountain 1981; DeMartini, unpubl. data). MEC's data are available for the period 1978-1986;during L981, however,only one cruisewas made during the queenfishspawning season). Because of the large variability in abundanceestimates among surveyswithin years, we calculatea weightedmean over all cruisesand years,weightings are the number of days from the mid-point of adjacent cruises. Estimates of the abundance of queenfish eggs are listed in Table B1a. Calculations analogous to those for queenfishare made to estimatethe abundanceof white croaker eggsbased on the fraction of white croaker in all yolksacand preflexion larvae. The croaker spawning seasonis defined as October through May for the period 1978-86. Estimatesare listed in Table B.1b for each of the eight croaker spawningseasons spanning 1978- 86. 8.2.2 Daily Egg Production In turn, we estimate daily egg production from mean egg abundancebased on the following relation: p=Z*N/(l-e-z), EOU (3) where P = daily egg production, N = mean egg standing stock, Z = instantaneous mortality rate of eggs (daily basis), B-4 I t = I and t duration ofegg stage (in days). We set the length of the egg stageat 2.5 days;this value is representativeof t small pelagic fish eggsat averagewater temperature(16.) in the Bight (W. Watson, I pers.comm.). In lieu of accurateempirical estimatesof queenfishand croaker egg mortality rates (see below), a constantegg mortality rate of.Z = 0.25 (-22%o per t day) is selectedbased on publisheddata for the northern anchovy(Smith 1985). Sinceanchovy, queenfish and croaker all have small pelagic eggs,the mortality for I eggsis probably similar for these taxa. Mortality rates which typicatly range from 10-60Voper day are typical for pelagicmarine fish eggs(reviewed by Dahlberg L979, t Table l.: meansurvivorship, S = 62Vo,SD= Z6Vo,n= 10 taxa). We standardizea t daily egg production per 1-m wide cross-shelfstrip to daily production within the Bight by multiplying the number/m by 5 x lff, where 500 km is the longshoreextent t of the Bight (AppendixA). We list estimatesof daily eggproduction in Table B.1. I 83 Queenfish and Croaker: Batch Fecundity I We estimate "batch fecundity" (the number of eggsreleased per individual I spawning)for queenfishby the methoddescribed by DeMartini and Fountain(1931) from samplescollected by the UCSB Fish Projectduring 1979,1980,1984,1985,and 1,986near SONGS. Fecundity-to-bodylength and fecundity-to-gonad-freebody weight regressionsare calculated,and meanbatch fecundityis estimatedfor females of averagebody weight in each year. For white croaker, an analogousestimate is madefor the pooled 1978-81spawning seasons using the data of Love et al. (1984) and M. l-oveQters. comm.). Table B.2 liststhe weight-specificfecundities (numbers B-5 I T of eggs/g), mean female body weights, and mean batch fecundities for queenfish and white croakerby relevantspawning season. t B.4 Queenfish and Croaker: Spavming Fraction t t "Spawningfraction" (the fraction of total mature females spawningduring a given time interval) is estimatedfor queenfishon a daily basis. During !979, female I queenfish in the San Onofre region spawned on average about once a week (Demartini and Fountain 1981). Spawningfraction is re-estimatedfor each of four ] additional years. The spawningfraction seemsto have varied little among recent years for queenfish (Table B.3; DeMartini, unpubl, data). I-ove et al. (L9sa) I estimatesthat female white croaker spawnedonce every 5.3 days during 1978-81, equivalentto a spawningfraction of 0.19(Table B.3). t 8.5 Queenfish and Croaker: Female Fraction I We estimate the "female fraction" (numbersor biomass)of adult queenfish using the sex ratio of adults caughtby lampara seine during the spawningseason. I Numbersare convertedto biomassby applyingthe generallength-weight regression, t W = 8.7x1O6SL3'11(DeMartini and Fountain198L, DeMartini et aL.1987,Appendix F) to the mid-points of 5-mm length classes,multiplying the mean weight of fish in that classby the frequencyof male and female fish, and then summingthe weights of all sample fish by sex over all length classes. Sex ratios are estimatedfor each year in which sufficient data are available. Ratios did not vary substantiallyamong years(Table B.a). B-6 t ,l For white croaker,we calculateweighted means of the sex ratios of croaker I caughtin otter trawls (day samples;6, 12, and 18 m depths)during 1978-85(SCE 1982,1983, 1984,1985, and 1986). These estimatesare used to determine the I fractionof females. t 8.6 Northern Anchow Stock Estimation T Table 8.5 summarizesavailable data on stock (numbersand biomass)of the t central subpopulationof the northern anchovyfor the period 1978-1986.Anchovy comprisethree stocksin the easternPacific; the central subpopulationinhabits the t region betweenSan Francisco and northern Baja (Vrooman et al. 198t). Literature t sourcesfor stockestimates are listedin TableB.5. t 8.7 Estimatesof Adult Stock Size I 8.7.1 NorthernAnchow I During 1978-86,estimated stock sizeof ancholy central subpopulationvaried t from a low of about 20 billion fish weighing300,000 MT (in 1984)to a high of about 50 billion fish weighing870,000 MT (in 1980)(Table B.5). The standingstock was t approximately58 billion fish but fish were small and total biomasswas only 652,000 MT. Average stock size during 1978-86was 37 billion anchory weighing about I 534,000MT (TableB.5). I t x B-7 t I 8.7.2 Queenfish t I Estimated stock sizes varies 60-fold, from a low of 12 million queenfish weighing400 MT in 1982to a high of 690 million fish weighingabout 21,000MT in I 1985(Table 8.6). For the entire nine-yearperiod from L978-L986,the average queenfishstock was an estimated140 million fish weighingabout 4,300MT (Table I B.6). T 8.7.3 White Croaker t Estimated stock sizes varies 50-fold, from a low of about 2.5 million fish t weighing235 MT in 1984to a high of L20million fish weighingabout 1L,500MT in 1981(Table B.7). During the eight spawningseasons from L978-1985,stock size of T white croaker averaged55 million fish weighingnearly 5,300MT (Table 8.7). t B.8 Potential Inaccuracies: Factors Affecting Stock Estimates T Three major factors contribute to stock size estimatesbased on the Egg t ProductionMethod. Theseare estimatesof: (1) eggproductionby the stock based on egg surveys,(2) eggproduction by the averagefemale individual, and (3) adult I female contribution to adult stock (Parker 1980, 1985). Egg production for I queenfishand croaker stockscannot be estimateddirectly becausetheir eggscannot be readily identified in plankton samples. I Of all potential sources of error, our method of estimating stock egg t production based on stock egg abundanceand an assumedegg mortality rate may t B-8 T t T t have introduced the most serious inaccuracies. As with the published anchovy I estimates,estimates of egg abundancein MEC's plankton samples have large variances. In addition, our procedure includes the added step of estimating egg t abundanceof a taxon basedon total unidentified egg abundance. The adjustment T factor we used is the fraction that yolksac and preflexion larvae of the taxon contribute to all yolksacand preflexion larvae (SectionB.2). This assumesthat egg T mortality of all taxa is proportionate to the mortality rates of yolksacand preflexion larvae of all ta,ra. This is probably a valid assumptionbecause the eggsof almost all t taxa are small (.9 1.1 mm diameter)and sharethe samewater-column habitat at t the sametime. n Another assumptionis that the mean egg abundancein the San Onofre- Oceansideregion is representativeof mean abundancethroughout the Bight. This t assumptionis probably weaker than our assumptionof proportionate egg mortality rates,because the abundanceof spawningfish probablyvaries regionally. However, I no data exist to evaluateit rigorously (see analogousargument legarding regional t variation in larval abundance,Appendix A). t A more likely source of error is our use of the averagemortality rate of anchovyeggs, instead of empirical estimatesfor queenfishand white croaker eggs. I The range in magnitude of estimates of egg production using bracketed egg mortality values illustratesthe potential effect that this assumptionhas on our T estimatesof stock size. Using the anchovymortality rate of 22Voper day (Z = .25) T over a 2.5 day egg stage duration, egg production is 54Vo of. egg standing stock (Table 8.1). If insteadwe had usedan eggmortality rate of llVo per day (Z =.ll) t over this interval, egg production would have been 46Voof egg stock. On the other t B-9 I t il hand, a mortality rate of 50Voper day(Z = .70) yields an eggproduction of 85%oof egg stock. Therefore, dependingon the true value of egg mortality rate, we may T have underestimatedqueenfish and croaker eggproduction (henceunderestimated adult stocks)by as much as 36Vo,or we might have overestimatedegg production I and stocksby as much as 17Vo. '[ For both queenfishand croaker, estimation of egg production per female is I basedon two parameters,batch fecundity and spawningfraction. This is because the females of these two taxa, like anchovy,spawn multiple times per spawning I season. For queenfish, our estimation of these parameters is based on a comprehensive,five-year series of data, and the precision of the estimatesduring t each of the five years is reasonable(Tables 8.2, 8.3). (Of course, the implicit l assumptionhere is that the batch fecundityand spawningfrequency of queenfishin the San Onofre-Oceansideregion is representativeof the bight-wide stock. Again, T we have no data to evaluate this assumptiondirectly, but our data have never suggestedany pattern to variation at sampling locations within the San Onofre- t Oceansideregion.) For white croaker, I-ove et al.'s (1984) estimates of batch t fecundity and spawning fraction are used. Without multiple-year data for comparison,we do not know how representativethese point estimatesof white T croaker are. I-ove et al. (I98\ do not provide measuresof the precision of their estimates. We can only concludethat becauseof fewer data on the eggproduction I of individuals, our estimatesof white croaker stock may be less accuratethan our estimatesof queenfishstock, but we cannotquanti$/ the relative levelsof accuracy. I I EPM-basedstock determinationsare also influencedby estimatesof female contribution to adult stock. For queenfish,characterization of sex ratios are based t B-10 ; I I T on samplestaken over eight to nine years off San Onofre. (Again, we have made ,t the reasonableassumption that sexratios in the region are representativeof bight- wide stock.) For white croaker,numerical sex ratios are basedon a long-timeseries t of data (1978-85)off San Onofre. The sex ratio in terms of biomassfor croaker, t however,has to be based on a qualitative adjustmentof the numerical ratio data. Thus, we have less confidence in the biomass spawning fraction estimates for t croaker than in our analogousestimates for queenfish. Poorer accuracyin estimating the spawning fraction for croaker contributes to our overall lower t confidencein the stock estimatesfor this taxa. However,even the most extremesex ratio values that are reasonable(say, 4-0.6) would have relatively little effect on t stockestimates compared to probableinaccuracies in estimatingegg production of J the averagefemale croaker and (especially)inaccuracies in estimating bight-wide eggproduction of the white croakerstock. I li t t I t I I t B-11 I I REFERENCES T T Bindman, A.G. 1986. The 1985 spawning biomass of the northern anchoyy. CaICOFI Rep. XXVII: 1,6-24. I Dahlberg, M.D. L979. A review of survivalrates of fish eggsand larvae in relation T to impact assessments.Mar. Fish.Rev. 4l: 1,-12. t DeMartini, E.E. and R.K. Fountain. 1981. Ovarian cyclingfrequency and batch t fecundityin the queenfish,Seiphus polirus: attibutes representativeof serial spawningfishes. U.S.Fish. Bull.79: 547-560. t DeMartini, E.E. and UCSB Staff. 1987. The Effects of Operations of the San T Onofre Nuclear Generating Station on Fish. Final Report, Volume 2 T (AppendicesA-U). Report submittedto the Marine Review Committee,Inc. December31. 1987. t Hewitt, R.P. 1985. The 1984spawning biomass of the northern anchory. CaICOFI I Rep. XXVI:17-25. T l-ove, M.S., G.E. McGowen,W. Westphal,R.J. I-avenberg,and L. Martin. 1984. T Aspects of the life history and fishery of the white croaker, Genyonemus lineatus(Sciaenidae), off California. U.S.Fish. Bull. 82: 179-198. T Lo, N.C.H. 1985. Egg production of the central stock of northern anchovy, I Engraulismordax, 1951,-82. U.S. Fish. Bull.83: 137-150. t B-12 T T I I Methot, R.D. and N.C.H. L,o. 1987. Spawningbiomass of the northernanchovy in I 1987.NMFS Admin. Rep. IJ-87-I4. (OctoberL987 revision). I Parker, K.R. 1980. A direct method for estimating northern anchovy,Engraulis I mordm, spawningbiomass. U.S.Fish. Bull.78: 541,-544. I Parker, K. R. 1985. Biomassmodel for the Egg Production Method. ln: An egg production methodfor estimatingspawning biomass of pelagicfsh: Application I to the northem anchovy,Engraulis mordm. u.s. Dept. commerce, NOAA I Tech.Rept. NMFS 36. R. Lasker,ed. pp.5-6. t Picquelle,S.J. and R.P. Hewitt. 1983. The northern anchovyspawning biomass for t the 1982-83california fishingseason. calcoFl Rep. XXIV: 76-28. Picquelle,S.J. and R.P. Hewitt. 1984. The 1983spawning biomass of the northern I anchovy. CaICOFI Rep. XXV: 16-27. I Picquelle,S.J. and G. Stauffer. 1985. Parameterestimation for an eggproduction I method of northern anchory biomassassessment. In: An eggproduction method for estimating spawning biomass of pelagic fish: Application to the I northem anchorry,Engraulis mordm. U.S. Dept. Commerce,NOAA Tech. I Rept.NMFS 36. R. Lasker,ed. pp.7-15. I Smith, P.E. 1985. Year-classstrength and survival of 0-group clupeoids. Can. J. Fish.Aquat. Sci.42: 69-82. B-13 I I Smith, P.E. and R.W. Eppley. L982. Primary production and the anchovy population in the Southern California Bight comparison of time series. I Limnol. Oceanogr.27: 1,-17. I Stauffer, G.D. 1980. Estimatd of the spawningbiomass of the northern anchovy I central subpopulationfor the 1979-80fishing season. CaICOFI Rep. XXI: 17-22. I Stauffer, G. D. and K. Parker. 1980. Estimate of the spawningbiomass of the I northern anchovy central subpopulation for the 1978-79fishing season. CaICOFI Rep. XXI: 12-t6. I I Stauffer,G. D. and S. J. Picquelle. 1981. Estimateof the spawningbiomass of the northern anchory central subpopulation for the 1980-81fishing season. t CaICOFIRep. XXII: 8-i.3. I Vrooman, A. M., P. A. Paloma, and J. R. Zweifel. 1981. Electrophoretic, I morphometric, and meristic studies of the subpopulations of northern anchovy,Engraulis mordm. Calif. FishGame 67: 39-51,. I I t I B-14 T TABLE 8.1. I Estimates of egg abundance and egg production for (a) queenlish and (b) white croaker. Estimates are on a spawning serasonbasis, with cruise estimates weighted by interral between cruises within spavming season. Also presented are estimates of the abundance of total unidentified petagic eggs, plus the I fractional contribution of the yolksac and preflexion larvae of queenfish (QFSHFRAC) and white croaker (WCRKFRAC) to all yolksac and prrcflexion larvae. These yolksac and preflexion estimates are used to subdivide total unidentified eggSinto queenfish and white croaker eggs. We estimated egg t production assuming that egg mortality, Z = 025 (Section B2). (a) I oueoNrrsn Utuo QUEENFISH QUEENFISH Srawr.uNc No. EGG EGG EGG 'QFSHFRAC- I SEASoN Cnursns ABUNDANCE ABUNDANCE PRODUCTION (#/M; x1d) (#/u;xrcs) (*/u;xIcs) I t978r2 9.1. L.7 0.89 0.182 r9796 5.5 1.0 0.511. 0.t76 198023 7.9 1.7 0.91 0.2r8 I 19811 L0.4 0.9 0.50 0.089 L9823 8.2 0.2 0.09 0.026 I 19833 0.4 0.20 0.078 19844 9.8 6.0 3.21. 0.685 19855 22.5 6.7 3.60 0.299 I L9864 6.9 0.8 0.43 0.078 9 yr Wtd. I MEAN 9.1, 2.1. 1.13 0.216 I (b) wHrrg cRoAKER Uuo WHrrECnoaren WHITECROAKER SPAWMNG No. EGG EGG EGG I 'WCRKFRAC' SeasoN Cnursss ABUNDANCE ABUNDANCE PRODUCTION I (#/M; x1d) (#/rr,r;xrd) (#/M;XLF) r978-79 9 5.6 2.7 L.45 0.489 L979-80 10 5.3 3.0 1.60 0.565 I 1980-81 2 1) 0.3 0.16 0.138 L98r-82 z 7.7 4.8 2.58 0.624 1982-83 2 4.0 3.0 t.62 0.752 I 1983-84 4 7.0 0.4 0.2L 0.056 198+85 5 5.6 1.0 0.05 0.018 t 1985-86 4 4.5 3.2 L.74 0.7t3 8 yr Wtd. I MEAN 5.4 )) t.2L 0.4n I B-15 I TABLE B.2. Estimates of batch fecundity and related parameters for (a) queenlish and (b) white croaker. I Estimated means, standard errors of means, and sample sizes are listed for each spavming serasonin which data are available. I I BATCH I FECUNDITY FEMALE NO. EGGS 1xrdy BoDYWr. (c) PER G I SPAwMNG NUMBER Seeson MEAN MnaNFeMALEsMo. MBaN SEM N I (a) oueexrtsH L979 15.2 45 872 6 339 21. 4 I L980 13.6 q 995 6 w tz r?6 1.984 9.4 35 295 5 268 L6 7L t 1985 L2.4 38 6?5 6 325 15 77 1986 13.1. rm 95r. 6 3n 15 75 I 5-yr mean 12.7 q 3r9 4-yr mean (excl.'84)a 1:}.6 4L 337 I I (b) wHrTE CROAKER I 1978-81 10.9 LOzb 1.0 4 I a 198+was an El Nino year. bLength frequencydata for adults (>16.5 cm TL) capturedat 18-109m depths(I-ove et at.1984,Pig. I 2) convertedto weight frequenciesusing the approximatelength-weight regression, W=0.011TL3'02 (Loveet al. L984,Figs. 3,4). c Length-specilicfecundity data providedby M. Love,VRG, OccidentalCollege. Convertedto weight- I specificfecundity using the length-weightrelation, W=0.011TL3.m et at.1984). lLove I t B-16 I I TABLE 8.3. I Estimated nsparvning (see fractionn Section B.4) for (a) queenfish and (b) white croaker. I Estimates are listed for each spawning season in which data are available. t I SPAWNING FRACTION SpawurNc No. I Snason MEAN SEM SAMPLES I (a) ourrurrsH r979 0.1.1 0.02 25 I L980 0.L5 0.04 19 Lg8r'' 0.16 0.06 11 I 1985 0.06 0.01 38 1986 0.08 0.02 35 t 5-yr mean 0.11" I (b) wHrTE CROAKER 1978-81 -_a _a I 0.19 a I No data on variance of estimate and sample sizes available (Love et al. L9B4). I I I I B. L7 I TABLE 8.4. Estimated nfemale fractionn (females/adults) for (a) queenlish and (b) white croaker. Mean I is averaged by month over the number of months (Mo). Estimates are listed for each spawning season in which data are available. I I FEMALE FRACTION I NUMBERS BIOMASS I SpawNttIc NUMBER FtsMALE NUMBER SEASoN FtsMALEs Mo. wT. (Kc) Mo. SAMPLES I (a) ouspNFrsH L979 0.47 872 6 0.58 39.4 6 I L980 0.32 995 6 0.46 39.8 6 1981 0.34 32L0 6 0.44 LLz.O 6 1982 0.n t523 6 0.32 45.7 6 I 1984 0.43 295 5 0.€ 10.4 ) 1985 0.35 625 6 0.44 23.5 6 I 1986 0.4r 951 6 0.47 38.5 6 7-yr mean 0.36 0.4 I 5-yr mean 0.39 0./A I (b) WHITE CROAKER 1978-81 0.524 0.55b I a Basedon numeric sex ratio for total white croakertrawled at 6-L8 m depthsoff San Onofre during I 1.978-1985(SCE 1982,1,983, L984, 1985, and 1986). b Numeric sex ratio (0.52) is adjustedfor faster growth rate and greater longevityof adult females I (l-ove et al. L984). I t B-18 I I TABLE 8.5. Estimated stock (in numbers and biomass) and mean body weight per individual adult for the central subpopulation of northern anchory, Engraulis mordax, during each of nine years I from 1978 to 1986. I MEAN StaNonc Srocr BODYWT. I Nuvnens BToMASS(MT) (e) SOURCES I r978 2.9r1910(a) 300,00ff rf Smith & Eppley 1982 L979 2.67"19t0(a) 400,00ff 15f Smith & Eppley L982; I Stauffer L980 I 1980 4.995,19t0(u) g7o,oo0d L7.4 Stauffer& Parker 1.980 1981" 4.75*1910(b) 635,000d t3.4 Stauffer& Picquelle, t 1981 I L98Z 2.26*1610(o) 415,000d 18.8 Picquelle& Hewitt, 1983 t 1983 5.82x1010(b) 652.000d lI.2 Picquelle& Hewitt, I r9u I Igp4 2.5716r0(u) 309,oood L2.0 Hewitt 1985 Bindman1986 t 1985 3.6919t0(b) 522,Md t4.5 1986 4.67"1910(a) 700,000e 15f Methot&I.o1987 I 9-yr mean 3.7x1010 534,000 15 I a Stock numbers based on estimate of stock biomass and an assumedaverage body weight of 15 g. b Stock numbers based on estimate of stock biomass and empirical data on mean adult body weight. c Stock biomass based on "Larva Census Method." I d Stock biomass based on "Egg Production Method." e Stock biomass based on "Stock SvnthesisMethod." I f Meao body weight estimated at i5 g, based on long-term average of known average body weights. I B-19 I TABLE 8.6. I Estimated spawning stock (in biomass and numbers) for queenfish. Estimates are provided for each ofthe years 1978-1986;differences among years in input data are noted. I I QUEENFISH ADULTSPAWNING STOCK I SPAWMNGSEASoN BIoMAss(MT) NUMBERs(xld) I r97ga 2,759 88 LgTgb 1,,L90 33 I 1980b L,949 70 I L9g1a L,616 52 t9824 391. L2 I 19834 6y 20 1984b 7,810 249 I 1985b ?n,96 69L 1986b t,757 50 I I 9-yr mean 4,yL LN I a No data availableon reproductiveparameters for individualfemales; stock estimate calculated using five-yearaverage (L979-80, 84-86) data on female fecundity,spawning fraction, and adult sex ratio, appliedto year-specificestimates of eggabundance and production. I b Stockestimated using year-specific data on femalefecundity, spawning fraction, and adult sexratio. I I I I B-20 I I I TABLE B.7. Estimated spawning stock (in biomass and numbers) for white croaker. Estimates are I provided for the years 1978-1986;differences among years in input data are noted. t I WHITE CROAKER ADULT SPAWNING STOCK I SPAWMNGSBasoN BIoMASS (MT) NuiaseRs(x106) I L978-79a 6,501, 67 1979-80a 7,r50 74 I 1980-81a 722 7 1981-82b fi,522 L20 I L982-83b 7,243 75 I 1983-84b 940 10 1984-85b 234 2 I 1985-86b 7,792 81 I 8-yr mean 5,?63 55 a Stock estimated using Love et al.'s (1984) data on female fecundity and spawningfraction, applied to I spawningseason-specific estimates of eggabundance and production. bNo dut" availableon reproductiveparamslsrs for individualfemales; stock estimate calculated using 1978-81data of [-ave et al. (1984),applied to spawningseason-specific estimates of egg abundance I and production. I I I I t B -21 This pageintentionally left blank. B -22 T I APPENDIX C I ESTIMATING THE ENTRAPMENT RATE OF YOUNG ADULTS I t C.l Introduction We cannot estimatedaily entrapmentrates for juveniles becausewe do not I have data on density of juveniles. Consequently,we estimate an averagejuvenile T entrapment rate according to an exponential rate of decrease from the daily entrapmentrate of post-flexionlarvae to the daily entrapmentrate of young adults I (Appendix D). In this Appendix, we estimate (1) daily inplant loss, (2) bight-wide standingstock and (3) the entrapmentrate of youngadults, by taking the ratio of (1) t to (2). I C.2 Inplant Loss and Bight-Wide Abundance of Young Adults I Technical Report C (basedon DeMartini et al. t987) presentsestimates of I yearly loss for Units 2 and,3 for pooled juvenites-adults(see Technical Report C, Tables 1'l and 12). We convert theseto daily lossesby dividing by 356. Table C.1 t lists theseestimates of daily inplant loss for juveniles-adultsfor each of the ten taxa I at risk asjuveniles-adults at SONGS. We report estimatesof loss at Units 2 and 3 as "ma:rimum" and "adjusted." Maximum losses assume that all individuals I entrapped die; adjusted losses debit diversion subtotals for the percentage survivorshipof fish dischargedby the Fish Return System. Table C.2 lists these percentagesurvivorship estimatesby taxon (from Technical Report C; based on DeMartini et a|.1987\. c- 1 I I Next we estimatethe fraction of young adults entrappedand in the spawning stock. On a taxon-by-taxonbasis, we identify a segment of the adult length I frequencydistribution of smallestbody size that represents25-50Vo of total adults entrapped.For this we use entrapmentdata from Units 2 and3. (Our rationaleis t to choosea fraction large enough to be within a factor of.2-4 of total adults, yet I small enoughto representa reasonablyshort segmentof the adult age distribution. For example,for queenfishyoung adults 10.5-11.4cm SL, equivalent to 1z-L5 t monthsof agerepresent 25Vo ofadults entrapped.) We usean analogousmethod to calculate the fraction that young adults contribute to total adult stocks:the total I length distribution is characterizedfor each taxon for which we had estimatesof adult stock size or for which published harvest data could be substituted for I estimatesof stocksize. I Table C.3 lists the length range representing"young adults" for each of the I ten target taxa and the fractional contribution of young adults to total adults for both SONGS' lossesand natural stocks (Table C.3). We also document data I sourcesin Table C.3. For anchovy,queenfish and white croaker, young adults I representa larger fraction of the numbersof lost adults. This is expected,given the greatersusceptibility of smallerfish to entrapment(Appendix D). t Next we provide estimates (or proxies) of the bight-wide abundance of I adults. Sourcesfor estimatesdiffer with taxa. For northern anchovy,we take estimatesof stock size from published papers and unpublished National Marine I FisheriesService reports; most anchovyestimates used the Egg ProductionMethod (EPM; Appendix B). We use a modification of the EPM to estimate stocks of queenfishand white croaker (seeAppendix B for details of calculation). Stock sizes c-2 I I cannotbe estimatedfor all taxa. In theselatter cases,the annual fishery harvestis I used as a minimum estimate of adult stock size. For commerciallyprotected taxa (California corbina,the basses),National Marine FisheriesService (NMFS) data on T the recreationalfishery are used(U.S. Depaftment of Commerce,1981, L983, 1985, I 1986,1987).For taxa subjectto commercialexploitation (e.g., California halibut), California Department of Fish and Game (CF and G) data on commercialcatches I are addedto the recreationalharvest data. I Table C.4 summarizesavailable data on the average annual harvestsand stock sizesof the adults of ten target taxa. Harvest data are partitioned into the I recreationaland commercialfisheries, if possible. I Table C.5 lists, by taxon for each of the ten taxa, the key input data used to I calculatethe entrapmentrate for young adults. Parameterslisted are daily inplant loss(L) and estimatedstock size (S). Sincethe complementof adult-equivalentloss I (1-R") for the old juvenile stage is equal to its entrapment rate multiplied by its duration, the duration of the old juvenile stageis to assistsetting up the data for T calculation. I I I I I c-3 I I C.3 Taxa Account: Discussionof Problem Data and Assumption Violations I C.3.1 Northern Anchow I I We believe we underestimateentrapment rate for young adult anchovies (E = -?-x10t0,Table C.5). However,we believethat E for anchoviesis actually I very low at SONGSfor the following reasons: Entrapmentrate for the old juveniles of this taxa includes our best, long-term data on stock numbers (S) and the I percentagethat young adults contribute to adult stock for any taxon on our list. Estimatedinplant loss of youngadult anchovies(9.5-9.9 cm SL, Table C.3) is known I to be low at Unit 1 (DeMartini et a\.1987). We estimate,however, that anchovies t longer than 9.0 cm SL are retained on the 3/8 inch mesh of the Units 2 and 3 screens,so entrapmentof youngadult anchovyat the new units shouldbe accurately I estimated;more thanglVo of total entrapmentoccurs in Units 2 and3. I C.3.2 Queenfish t We have confidencein our estimateof E for queenfish(7 x 10{; Table C.5) I for the following reasons: First, the estimate of inplant loss of old juvenile queenfishis amongthe bestfor anytaxa on our list; youngadults (10.5 -11.4 cm SL) I are retained on the screensof Unit 1, as well as Units 2 and 3, and our SONGS' entrapmentestimates are precise (numbers:CY=8-13Vo; DeMartint et al. L987, I Appendix G, Table 1). Averagestock size of queenfishwas estimatedbased on the I Egg ProductionMethod, using five yearsof extensivedata (AppendixB). c-4 I I C.3.3 White Croaker I We think that our estimateof E for white croaker (3x10+;is reasonablebut I our confidencein this estimate is less than that for queenfish. Estimated inplant lossesof old juvenile croaker are basedon a large amount of precisedata (numbers: I CY=25'32Vo;DeMartintet al. 7987,Appendix G, Table 2). White croakerare fully retained. Therefore,entrapment data are accuratefor young adultsthat are 13.5- I 13.9cm SL. I Croakerloss estimates from 1,983to 1986are undoubtedlylower than the I long-term averagebecause of the offshore emigration of adults and recruitment failure during the El Nino years,both of which contributed to low abundanceof I adults nearshoreduring 1983-86(DeMartini et at. 1987). Stock size estimatesfor I white croaker are basedon fewer data, and thus are probably not as representative as our queenfish estimates. We estimate stock sizes of white croaker with I confidencefor the period 1978-1981only; during this period, abundancewas higher than during the El Nino years which are used to characterizeinplant loss. If the I 1979and 1981stock abundance and 1983- 1986inplant lossesare usedto determine entrapment rate, the rate will be an underestimate. However, even if the adult t stock size is lowered by an order of magnitude,the estimatedentrapment rate will I be reducedby only L/3 (-2xI0{). A similar result is found if averagedaily lossesat Unit 1 during 1978-1980are used to estimate combined Unit 1 and Units 2 and 3 I lossesfor this period, had the new units been operational. Using a factor of 100 times greater entrapmentof white croaker (total in numbers)at both new units t versusUnit 1 (DeMartini et al. 1987, Chapter 2, Table 14), lossesat Unit L (an I estimateof 50 pooled juveniles-adultsper day) plus the new units (adjustedfor I c-5 I I I FRS-dischargesurvivorship), might have totaled -4000 total white croaker per day. Generouslyassuming that one-fourth of thesefish are adults,and that one-fourth of I theseadults are young adults,daily lossesof young adult croaker might have been -250 per day. Compared to averagebight-wide abundancesof 55 million adults I (and 4 million young adults), the estimateof E still would have been only about 6 x I 10-s,i.e., still more than two orders of magnitudelower than the entrapmentrate of post-flexionlarval croaker. Thus, any reasonablecombination of valuesindicates a I relatively low entrapmentrate for the youngadult stageof white croaker at SONGS. I C.3.4 Taxawith Inplant LossesEstimable for Old Juveniles T Young adult lossesare estimable for three additional taxa (black croaker, I kelp and sandbasses -- Table C.1). Although we are not able to estimatestock size for thesetaxa using the eggproduction method, we are able to estimatestock sizeof I the bassesfrom long-term fisheriesharvest data (Table C.4). The magnitudeof the bassharvest data (-4 million fish per year) is probably an order of magnitudeless I than stocksize, so estimatedentrapment rate basedon harvestdata (E = 2x 10-8)is I overestimated. An entrapment rate as low, or lower than, L0-8is negligible. However, the magnitude of the daily entrapment rate of juveniles is not the only I factor that influencesoverall adult-equivalentloss. Duration of the juvenile stage and magnitude of the post-flexion entrapment rate are also important (Appendix I A). For these reasonswe hesitate to provide a numerical estimate of E for the basses,however we believethem to be very small. I I In lieu of harvest data, using conservativeestimates of stock numbersof black croaker (1ff) would result in similarly trivial entrapment rates for the old I c-6 I I juvenile stagesof these two taxa (10-sand 107, respectively). Again, because the T magnitude of the rate for old juveniles is not the only important factor, we hesitate t to provide a precise value. I C.3.5 Taxawith Inplant InssesInestimable for Juveniles I There are no length data for California corbina, grunion, jacksmelt, and salemaentrapped at SONGS. For each of these taxa, the total number of fish I entrappedis used to estimateinplant loss of older juvenilesand therefore,older juvenile loss is underestimated. For all exceptsalema, however, fisheries' harvest I data are available as minimum estimatesof stock size. For salema,a low estimate I of stocksize (106 fish) is usedto providean underestimateof S (Table C.5). The net result of a likely overestimateddaily lossand a likely underestimatedstock size in I all casesshould have producedan overestimateof E. The calculatedvalues range from 10s to L0{, but we do not give them undeservedimportance by including them t in results. I C.3.6 GeneralPatterns for AII Taxa I Each of the ten taxa at risk to entrapmentas juveniles-adults at SONGS has a low entrapment rate as an old juvenile. This is the case for taxa with high entrapment rates as post-flexion larvae (queenfish,white croaker), as well as taxa with very small post-flexionrates (e.g., the basses).We attribute the generallylow E's primarily to the rapid increasein swimmingspeed (ability to avoid entrapment) at old juvenile-youngadult body sizes,and secondarilyto changein microhabitat as fish move offshore from the region of the SONGS' intakes as they age and grow. c-7 I-ossesduring the juvenile stagecan be relatively large even when E is small. This can occur if the duration of the juvenile stage is long or if our estimate of entrapmentrate is high. c-8 I I REFERENCES I Clark, F.N. 1925. The life history of Leuresthestenuis, an atherine fish with tide- I controlled spawninghabits. calif. Div. Fish Game,Fish Bull. 10: 1-51. I Clark, F.N. 1929. The life history of the California jacksmelt, Atheinopsis t califomiensis.Calif. Div. FishGame, FishBull. 1,6:3-22. I DeMartini, E.E. and UCSB Staff. 7987. The effects of operationsof the San onofre Nuclear Generating Station on Fish. Final Report, Volume 1 I (Chapters 1-4) and Volume 2 (AppendicesA-U). Report submitted to the t Marine ReviewCommittee, Inc. December31,lgg7. I Joseph,D.C. 1962. Growth characteristicsof two southernCalifornia surf-fishes, the California corbina and spotfin croaker,family Sciaenidae.CaW Dept. l Fish Game,Fish Bull. 1,19:t-54. I Love, M.s., G.E. McGowen, w. westphal, R.J. I-avenberg,and L. Martin. 1984. Aspects of the life history and fishery of the white croaker, Genyonemus l linearus(Sciaenidae), off California. U.S.Fish. Bull. 82: L79-198. I Marine Review Committee, Inc. 1989. Final Technical Report C. Entrapment of I juvenile and adult fish at SONGS. Report to the California Coastal I Commission. I I c-9 I I t United StatesDepartment of Commerce. 1981. Marine recreationalfisheries statisticssuryey, Pacific coast, L979-I980.Current Fishery StatisticsNumber I 832I. Washington,D.C. I United States Department of Commerce. 1983. Marine recreational fisheries T statisticssurvey, Pacific coast, 1981,-1982.Current Fishery StatisticsNumber 8323.Washington, D.C. I United StatesDepartment of Commerce. 1985. Marine recreationalfisheries I statisticssurvey, Pacific coast,1983-1984. Current Fishery StatisticsNumber 8325.Washington, D.C. I l United States Department of Commerce. 1986. Marine recreational fisheries statisticssurvey, Pacific coast,1985. Current Fishery StatisticsNumber 8328. I Washington,D.C. I United States Department of Commerce. L987. Marine recreational fisheries I statisticssurvey, Pacific coast,1986. Current Fishery StatisticsNumber 8393. Washington,D.C. t T t I I c-10 I I I I TABLE C.1. Estimated daily entrapment loss for each of ten select taxa considered at risk to I entrapment as juveniles-adults at soNGS. Loss estimates for pooled juveniles- adults are subdivided into juveniles and adults, and the latter presented as TOTAL ADULTS anil YOIJNG ADuLTs. Loss estimates arc for the 39-month period from May l9fft-August 1986, and include all operations at SONGS' Units 2 and 3. Loss I estimates at the new (MAD units include a "maximum" (assuming that all nadjustedn entrapped fish die) and an (ADJ) (ie" with the diversion component adjusted for survivorship of FRS-discharged fishes). The nadjustedn value is the I better estimate. I I ----- ESTIMATED DAILY LOSS (TNNUMBERS)--- PooLED I Taxon JUvs.ADs TOTALADULTS YOUNGADULTS Max ADr MaY Anr Marr ADr I Black croaker 1. 0.35 0.08 0.03 0.03 California corbinaa 4 0.9 no dataa no dataa I Grtrniona 1 0.85 no dataa no dataa JacksmelF 80 M no dataa no dataa 't.13 I Kelp & sandbasses 8 2.5 3.91. 1.25 0.36 I Northern anchovy 11450 r4L6 457 56 21i ?5 Queenfsh 3080 Iffi4 816 424 2L2 110 I Salemaa 39 t2 no dataa no dataa White croaker w ?50 0.98 0.75 I a No lengthfrequency data exist for SONGS'inplant5amples. I I I I c- 11 t I TABLE C.2. I Estimated percent mortality of FRS-diverted individuals,of select speciesat SONGS' Units 2 and 3. SeeTechnical Report C., Table 16. Estimates are based on results of I noffshore occidental college's survivorship Testsrn or, if survivorship data are lacking for the particular species, are based on the survivorship of lishes in the appropriate size group (nsmallrn nMedium,n or olargen). I T I RELEVANI Esr.VoDw. SIZE GROUP SURvlvoRSHIP I Black croaker M 77Voa California corbina L LNVoa I Grunion S 68Voa Jacksmelt M 77Voa T Kelp & sandbasses L IffiVoa I Northern anchovy S 97Vo Queenfish S 68Vo I Salema M lNVo White croaker S 48Vo I a Diversion survivorship based on body size. I T I I I c-12 I I t I TABLE C.3. nyoung Delinition of the adult" stage (inclusive length range) for each of ten select I taxa at risk to entrapment as juveniles-adults at SONGS. Also noted for each taxon is the fractional contribution (in numbers) of young adults to total adults for t SONGS'Units 2 and 3 intake lossesand the natural stock I YOUNG ADULT I FRACTIoNAL LENGTH RANGE Co}rrnreuloN To ADULT I TaxoN (sL,cM) INPI-A,NTLoSS NATURALSToCK Black croaker 22.0-22.9 0.17 inest.b I California corbinaa no dataa no dataa inest.b Gruniona no dataa no dataa inest.b I Jacksmelta no dataa no dataa inest.b I Kelp & sand basses 2r.o-2r.9 0.29 inest.b Northern anchovy 9.5-9.9 0.6 0.15c I Queenfish 10.5-L1.4 0.?5 0.13d Salemaano dataa no dataa inest.b t White croaker L3.5-13.9 0.28 0.07e I a No length frequencydata exist for SONGS'inplant samples. Standardlengths in cm from the literature are as follows: California corbina 27.8 (Joseph 1%2); grunion 11.9 (Clark 1925); jacksmelt18.5 (Clark 1929);salema 11.5 (DeMartini unpubl.) I b No comprehensivedata exist on sizecomposition of stock. c Estimate based on length frequencydata for the southernCalilornia segmentof the central subpopulation(CF&G SeaSurvey data for the years1979 - 1985). d Queenfishfrom lamparaseines near SONGS (night; 5-16 m depths;Mar-Aug 1984,1985, and I 1986). e White croaker from San Pedro-areaotter trawls (see Love et al. L984,Figure 2: 18-109m I depths;Sept 1972-Feb 1980). I c- 13 I TABLE C.4. I Estimated average SONGS' entrapment loss (numbers, daily) and annual fishing harvests (in numbers) of TOTAL ADULTS for each of ten taxa at risk as juveniles- t adults at SONGS. Inplant loss estimated from mean SONGS' Units 2 and 3 data for the 39-month period May 1983-August 1986. Loss expressed as nmaximum" (assuming 1007oloss of diverted lish at new units) and nadjustedn (corrected for survivorship of diverted fish). Average presented t annual fishing harvests are as minimum estimates for population sizes. Harvest summaries include commercial (8 years: 1978-1985) and (or) recreational catches (7.5 years: mid-1979 through 1986; U.S. Dept of Commerce L981, 1983, 1985-87),as appropriate for each species. I -.- TOTALADULTS T INPTAI\rI Loss AVERAGE (DATLY) ANNUALCATCH STocKSIZE TAxoN ADJ SPoRT CoMM (#s) I Black croaker 0.08 no data no data no data California corbinaa no data 66x103 trivial no data t Gruniona no data 19k103 trivial no data t JacksmelF no data 36ox1o33ox1o3(u) no data Kelp & sandbasses 39L L.25 4L82LLG trivial no data Northern anchovy 457 56 <3ox1d 2x10e(b) 3.11910(c) Queenfish 816 424 554x1d 4ox1o3(b) 1.4x108(d) Salemaa no data no data trivial no data White croaker ?3?5xr03r80x103(b) 5.5xto7(") a Assumesharvest comprises adults only. b Biomass(lbs.) convertedto numbersusing the following estimatesof mean body weight for harvestedadults: (anchovy:15g/fish; jacksmelt: 100g/fish; queenfish: 5Og/fish; white croaker: 100g/fish). I c Value is the 9-yr averagefor the period 1978-l-986. d Value is the 9-yr averagefor 1978-86. e Value is the 8 spawning-seasonaverage for 1979-86. I I c-14 t I TABLE C.5. Estimated SONGS' Units'2 & 3 entrapment losses (numbers, daily) and respective I bight-wide abundance (in numbers) for young adults for representative stages of each of ten taxa at risk as juveniles-adults at SONGS. Duration of the old juvenile stage is noted (see Appendix D). nMaximumn (MAX) losses are provided (assuming I that all fish entrapped at the new units die), in addition to nadjustedn (ADJ) Iosses (where total entrapment at Units 2 & 3 is corrected for the estimated percent t sunival of FRS-diverted fishes). Adjusted values are our better estimates of loss. I INPI-A,rvrLoss (L) DURATIoN (Darlv) Esnnraneo (INDAYS) TAxoN SrocK(S) I Max ADJ L/s JUVSTAGE I Black croaker 0.03 0.01 106(a) inest.f California corbinae 0.64 OOxTOF(u) inest.f na t Grunione 0.85 19k103(b) inest.f Jacksmelf 80 44 396y163(u) inest.f I Kelp & sand basses 1.13 10-1 41165(u) inest.f Northern anchovy 2L2 ?5 5.5x10e(c) 4.33x10-e 255 t Queenfish 2r2 1.L0 1.8x107(o) 6.11x10{ 288.5 Salemae 39 L2 166(a) inest.f na White croaker 0.98 0.75 3.8x106(d) L.97xL0-7 n5.5 a Natural stockinestimable and no harvestdata exist; a conservativevalue is usedto allow computation. b Natural stockinestimable; value used is the annualharvest (of assumedadults) as proxy for stocksize of youngadults. c Value is the averageof recentadult stockestimates (Table C.4), correctedfor the fraction that youngadults contribute to the stock(Table C.3). d Value is the averageof EPM-basedestimates of stocksize (see Appendix B andTable C.4), correctedfor youngadults (Table C.3). e Inplant lossestimates for total juveniles-adultsused as basis for conservativeestimate of inplant lossof adults. This grosscalculation was necessary for the 4/10 selecttaxa for which data on sizecomposition of entrappedfish are lacking. f Entrapmentrate deemedinestimable because of insufficientdata with which to approximate abundance(S) in determinationof ratio. c-15 This page intentionally left blank. I I APPENDIX D I ESTIMATING JTIVENILE ENTRAPMENT RATE t I D.1. Outline of Methods As discussedin Section2.2, if the entrapmentrate for immatures of age t is I e(t), then the averagerate is I ei = I e(t)dt/d; I the integral being from t = t;, the beginningof the stage,to t = t; * d1,the end. In this Appendix, we will describethe entrapmentrate as a function of body length, T e(b), rather than of time. Sincebody length is assumedto grow linearly with time I (i.e., the fish addsa constantamount of body length per day),the averagerate is I ei = I e(b)db/t the integral being from b = b1,the body length at the beginningof the stage,to b = I b; * q, the length at the end; q is the rangeof body lengthsfor the stage. l A fish will be entrappedby SONGSduring a given time interval if (a) it is in the packageof water withdrawn in that interval and (b) it is unable to escapefrom the water before it is withdrawn. We define the availability of fish of a given body length as the entrapment rate that would obtain if these fish drifted passivelywith the water. Thus, in the terminologyof Section2.3."J., D-1 t A(b) = Wps/WsDs. I t We define the vulnerability of a fish of a given body length as the probability of it failing to escapefrom a packageof water that is withdrawn. The entrapment I rate is then the product of availability and vulnerability,i.e., e(b) = A(b)v(b). It seemsreasonable to assumethat, in wlnerability and availability, early juveniles are like late larvae, and late juveniles are like young adults. Thus estimates of entrapment rate may be obtainable for species for which the vulnerability and availability of late larvae and early adults can be determined. Since plankton are assumed to move passively with the water, the vulnerability of postflexionlarvae is L. Consequentlythe availabitityof late larvae is their entrapmentrate. Young adult wlnerability and availability are not so easyto estimate. Three numbers are needed: the numbers entrained per unit time, the relative density in the neighborhood of SONGS (as compared to other depths), and the Bight-wide population. Of these,the first is obtainableby inplant sampling(Technical Report C), and an approximationto the secondis given by the results of lampara sampling in the 5-L0m depthzone (Interim TechnicalReport 3). However, estimatesof the Bight-wide population (or equivalently, of the average density in Blocks A-E) are lacking for all but two of the populations D-2 I I sufferingjuvenile entrainment(Table C.5). Egg production methodsare neededfor I these estimates. The lampara catchesare suitable for estimatingrelative densities but not for estimatingtotal population size: fish actively avoid being caught,so the I estimateddensities need to be multiplied by an unknowncatchability coefficient. I Fortunately, these two exceptionsare queenfishand white croaker. These I are the most important cases,since they (togetherwith northern anchovy)make up the great majority of entrainedlarvae and juveniles,and (unlike anchoqy)suffer the I highestproportionate losses. The remainderof this Appendixconcerns these cases. , Even for these cases,some assumptionsabout the data are needed. The t queenfish estimate given in Table C.5 is the product of the total adult stock, as estimated by the egg production method, and the fraction of that stock which is I young, estimated by the fraction of young adults in lampara catches. This may overestimatethe numbers of young adults, since the lampara catchesare made in t the shallower part of the range, where the ratio of young adults is greater. The I estimateof the fraction of youngwhite croaker adultsappears more reliable, sinceit is basedon otter trawls,which are takenfurther offshore. I D.2 Minimum and Maximum lengths, Availability and Vulnerabitity for Queenfrsh I and White Croaker. I For queenfish,the minimum length of juveniles is about bmin= 2 cm (Table E.l.A) and the maximum length is the minimum length of young adults, about b,',u* T = L0.5cm (Table C.3). The wlnerability of enteringjuveniles is taken to be I Vq(2) = 1, I D-3 I t I as for postflexion larvae, so the availability is the entrapment rate of postflexion larvae (Table A.3), I Ao(2) = 0.00101. I I To estimatethe availability of young adults,we use A = RwRo, where Rw is the fraction of water in the Bight that is withdrawn by SONGS each day, and Rp is I the ratio of the density of young adults near SONGS to the density in the Bight. (Thus RwRo = WsDs/WsDs, but we now use the sameunits for Ws as for Ws, and I the samefor Ds asfor De.) I The amount of water withdrawn per day isn on average,about 6.8E+06 l (AppendixA" SectionA2). I The amount of water in the Bight is the volume in a l-meter strip (from the shoreto the outer edgeof Block E) multiplied by 500,000,the length of the Bight in meters. The volumesof l-meter stripsof blocksAo B, C, D and E are 4,9,30, 55 and 110thousands of m3respectively (Interim Technical Report 5. Fish larvae and eggs,Appendix B). Thusthe volumeof waterin the Bight is about 1011m3. Accordingly,we take Rw = 6.8x10s. A rough estimateof the ratio of the densityof young adults near SONGS to their densityin the Bight generallycan be obtainedfrom Table 2 of.DeMartint et al. (1987,Vol 1). We subtractthe densitiesof adult malesand adult femalesfrom the densitygiven for older juveniles and adults. We do this for the operational period D-4 t I only, and for the Impact stationsonly, sincethere may be a behavioralreaction that I hasled queenfishto avoid the SONGSintake area. The differencesare 6 (NI) and 0 (FI) for the 5 - 10m depth zone,and2 and2 for the 11 - 16 m zone. We tal I About 2L2 yotng adults are entrappedper day, not adjustingfor those saved T by the Fish Return System,which doesnot savejuveniles. The total standingstock of young adults is estimatedby the Egg ProductionMethod to be 1.8*L07(Table I C.5). Thusthe entrapmentrate for youngadults is the ratio, 11.8x10{. I Combining availability and entrapmentrate, we estimatethe wlnerability of youngadults to be Vo(10.5)= 11.8x10-6/0.00051= 0.023. D-5 I I For white croaker, we obtain bmin = 1.9 cm and b-"* = 13.5 cm. (Tables E.1.A and c.3). The wlnerability of postflexion larvae is again taken to be I Vws(1'!) = l' I so the availability is the entrapmentrate (Table A.3), I Awc(1.9)= 0.000522. I There are no separatefigures for adult and immature white croaker, so we use the totals,which shouldreflect mostlyyoung adults. (Older white croaker adults tend to be further offshore.) Averagedensity per lamparahaul is29/2 for the 5-10 I m depth zone (taken as giving the densityin A-B Block) at the Impact stationsin the l operationalperiod and 1 for the 11-15m zone (C Block) (DeMartini et al. 1987, Table 2). Assumingthere are no immaturesbeyond C Block, calculationssimilar to those for queenfishgive the ratio of A-B densityto A-E density to be Ro = 16.7. Thus the availability of late juvenilesis Awc(13.5)= 16.7x6.8x1}s= 0.001135. Approximately 0.98 young adults are entrapped per day, from a standing stock of about 3.8x1ff (Table C.5, again using the maximum entrapment figure). DMding this by the availabilitygives a wlnerability of Vwc(13.5)= [0.98/(3.8x106)]/0.001135= 0.00023. D-6 t I D.3 The Shapeof Availability and VulnerabilityFunctions I We assumethat the availability and wlnerability functions at the beginning I and end of the juvenile stageare as given in the previoussection. However,we do not know how soon the late juvenile valuesare reached. The soonerthis occurs,the I lower will be the averageentrapment rate. The estimatesof entrapment in this Appendix are based on different guessesat the rapidity with which adult levels of t availability and especiallywlnerability are reached. I Availability. The evidence from mid-water lampara samplesof queenfish I suggeststhat juveniles of 6 -'7 cm,roughly midwaybetween 2 cmlawae and 1,0.5cm young adults,are distributed more like adults than like larvae. We have used three I models,one assumingslow linear change,so that the young adult distribution is reached only at adult length, another assumingfast linear change,with the young I adult distribution reached midway between postflexion and young adult, and the I averageof the two. Changesin availability functionshave only a small effect on the estimatesof losses,because availabilities of post-flexion larvae and young adults I differ only by a factor of trvo. Vulnerabilit)'. The decline in vulnerabilitywith length probably depends mainly on swimmingspeed. Small fish are more likely to be entrappedthan large fish becausesmall fish are lessable to outswimintake currents(Hanson et at.1977; DeMartini et al. 1985;Schuler and Larson 1975;Larson 1979\. We expect a sharp reduction in vulnerability when the fish's maximum swimmingspeed is equal to 50 cm/sec,the averagevelocity of water at eachof the D-7 SONGSintakes (Units 2 and3) (SCE 1987,Tables 1-5). (The averagevelocity at the Unit L intake is about 70 cm/sec,but this report concernslosses due to the new Units alone.) This maximum speed, which can be maintained for only a few seconds,is known as "burst" or "critical" speed, and is a measure of the brief anaerobicperformance required when attemptingto outswima predatoryfish (or an I intake). T Present theory and empirical data indicate that several factors control swimmingspeed. Most importantis bodylength (Blaxter 1969;Webb 1975;Wardle 1975, L977) and then frequency of the tail beat (Hunter and Zweifel 1977). Amplitude of the tail beat is a constantproportion of body length, averagingabout 0.2 x Total Irngth for the upper range of swimmingspeeds we are concernedwith (Bainbridge 1958; Van Olst and Hunter 1970; Hunter and Zweifel 1971). Of course,mode of locomotionis alsoimportant (e.g., does the fish swim like an eel or like a bass),but all of the taxa at risk to entrapment as juveniles at SONGS are carangiformswimmers which swim by flexing their posterior body andfor caudalfin (Lindsey 1978). For our purposes,estimates of burst swimmingspeed based on body length alone must suffice,because we lack specificdata on tail beat frequency. The latter data exist for only a few local taxa (ack mackerel,Pacific mackerel:Van Olst and Hunter 1970;Hunter andZweifel1971), and the juveniles-adultsof neither taxa are at major risk to entrapmentat SONGS. Our estimatesare based on the generalizationthat carangiform swimmers are capableof burst swimmingspeeds that increasewith total body length raised to D-8 I I a minimum of the 0.5 power (for salmonids)to a maximum of less than the 1.0 I power (for herring-likefishes) (Blaxter and Dickson 1959;Bainbridge 1960;Brett 1965;Fry and Cox 1970). Swimming speed may approach a linear relation with I body length,but in generalthe increaseappears to be less than linear (reviewedby I Webb 1975). For example, burst speed increasesas a decelerating function of increasedbody length in small clupeoidJike, gadid-like, and salmoniform fishes t (Webb 1975; Wardle 1975, 1977; Hartwell and Otto L978; Turnpenny 1983; t Turnpennyand Bamber 1983). Burst swimmingspeeds can rangefrom about 25 body lengths/secin 5-10cm T fish to much less than 10 body lengths/secin fish greater than 20-30 cm long t (Wardle 1975,1977). Fish that are 10-20cm long are capableof speedsof about 10 body lengths/sec. The observationsof Dorn et al. (1979) support the "10 body t lengths/sec"rule. The burst speedsof five taxa of local (sub)carangiformswimmers (including white croaker,one of the taxa on our list) averaged8.5 body lengths/sec I and ranged from 6-11 body lengths/secfor specimens10-20 cm long (Dorn et al. I 1979,Table 1). I Thus, in terms of published data for typical nearshoreCalifornia fishes and for small herring-like,perchJike, and bass-likefishes elsewhere, a body length of T about 5 cm seemssufficient to achievea burst speedof 0.5 m/sec, the velocity of I water enteringthe intakesat Units 2 and3. t This appears more likely to overestimatethe true critical length than to underestimateit. The "norm" of 10 body lengths/secapplies usually to largerfish, I which are usuallycapable of fewer body lengthsper secondthan smallerfish. For I D-9 I t t example,if swimmingspeed is proportional to body length raised to the 0.75power (midwaybetween the rough minimum of 0.5 and a generousmaximum of 1), and a I L0 cm fish is capableof 10 body lengthsper second,then a fish of only 2.8 cm is capable of a burst speed of 50 cm/sec. At the other extreme, if speed is I proportional to body length and a 10 cm fish is capableof only 8.5 body lengths/sec, I as for larger white croaker, then a fish needs to be 5.9 cm to be capable of 50 cm/sec. I Our estimatesof the vulnerabilitvfunction all havethe form t ",'l;J::;l:I:;:, I where b"'it is the critical body length at which the fish is able to escapefrom water l being drawn in to Unit 2 or Unit 3. I Thus we assumethat vulnerability drops from the postflexion rate to the I adult rate as soon as the fish is able to swim fast enoughto escapea parcel of water that is at the entrance to the intake. The adult rate is not zero: some adults I continue to be entrained, presumablydue to surge,poor visibility, and confusion about escapedirection. I t One objection to this function is that wlnerability is likely to change continuously,rather than in a single step. However,since the proportional change I in availability is far less than that in wlnerability, the estimated entrapment rate dependsalmost entirely on the average of the vulnerability function. Thus any t function havingthe symmetryproperU V(b.,ir - x) + V(bu, * x) = constantwill lead I D- 10 I l I I to essentially the same entrapment rate. (Large values of x, for which either bcrit- X t or b.r1s+ x is outside the range of juveniie lengths, will have V(b"n, - x) = V(b''6) or V(b.rt * x) = V(b**), whichever is appropriate.) We have merely picked the I simplest of these. I We usethree estimatesof b"11,roughly bracketing the range(2.8 to 5.9)given t above:3,4,5and 6. I We arguedabove that the speedis likely to be lessthan 5. However,burst t speedis not the only factor in escape. The fish must realize it is in danger,try to escape,and swim in the right direction to do so. If the fish tries to escapebefore it t hasreached the intake entrance,the water velocity will be less (it decreasesroughly in proportion to r-3l2,where r is the distancefrom the entrance),so a lower burst I speedwill suffice: smaller fisheswill be able to escape. If the fish tries to escape after entry, turbulence,confusion and the need to maintain burst speedfor a longer I period will make the task harder: larger fisheswill be unable to escape. We found I only a few studies that assesswlnerability based on swimming speed of fishes at power plants (Schulerand Larson 19751'Dorn et al. 1979,Harnvell and Otto L978, t Turnpenny 1983,and Turnpenny and Bamber 1983). These did not addressthese t questionsfor the specieswe are concernedwith here. I I D-11 I D.4 Summary I t The basic equation used to determine the fraction of juveniles escaping entrapmentis t E = e*pt -d I A(b)V(b) db) l where d is the time spentin the juvenile stage,b is body length,A is availability,V is wlnerability, and the integral is from bminto b."*, the ma,ximumand minimum I juvenile body lengthsof the taxon. t Three functions (high, middle and low) are assumedfor availability and four I for wlnerability, yielding t2 estimatesof entrapmentaltogether. Our guessis that the correct value is between those given by critical lengths of 4 and 5, with the l averagevulnerability function. I The three availability functionsare: t Ar(b) = tl -F(b)lA(b.i,) + F(b)A(b."")forb < b-io = A(b'"*) for b > bria T where F(b) = (b - b-i")/(bmro- b*6) and bmio= (b,* + b,"i^)/z; &(b) = tl -c(b)lA(b.in) + G(b)A(b.*) I where G(b) = (b - b.i")/(b.""u - b*in)i and the averageof these. Ar is the low n estimateif A(b-i") < A(b'"*) as for queenfish;otherwise Az is the low estimate,as for white croaker. The averageis alwaysthe middle estimate. I For vulnerability,the functionsare: I V(U; = V(b'i") = L forb S bcrit = V(b,n*) forb > b.,it D-12 I I where bcrit= 3,4,5 and 6. T Forqueenfish,d = 288.5,bmin = 2,b^u* = 10.5,A(2) = 0.00101,4(10.5) = I 0.00051,and V(10.5) = 0.023.For white croaker,d = 275.5,bmin = 1.9,b,,,* = 13.5, I A(1.9) = 0.000522,4'(13.5) = 0.001135,and V(13.5) = 0.00023. t The entrapment rates, probabilities of avoiding entrapment, and adult equivalentlosses that follow from these functions are given in Table L. Again, our I guessis that the correct value is betweenthose given by critical lengthsof 4 and 5, I for the averageavailability function. T No estimate is possible for the remaining species whose juveniles are entrapped,because we do not haveestimates of the entrapmentrates of their adults. I The juveniles of these species,relative to their larvae, are less susceptibleto entrainment than are queenfish, becausethey live further from the intake and I nearerto the bottom. I I I I I I I D- 13 I I REFERENCES t t Bainbridge,R. 1958. The speedof swimmingof fish as related to the size and to the frequencyand amplitude of the tail beat. J. Exp.Biol. 35: 109-133. I Bainbridge,R. 1960. speed and staminain three fish. "r.Exp. BioI. 37: 129-1.53. I Bla: Brett, J.R. 1965. The relation of size to rate of orygen consumptionand sustained t swimmingspeed of sockeyesalmon (Oncorhynchusnerka). J. Fish. Res.Bd. Canada22: 1491,-1501. I I DeMartini, E. and UCSB Staff. 1985. Annual Report of the UCSB Fish Project for the period: June 1984through May 1985. Report submittedto the Marine T ReviewCommittee.Inc. I DeMartini, E. and UCSB Staff. L987. The effectsof operationsof the San Onofre I Nuclear Generating Station on Fish. Volume I. Report to the Marine Review Committee.Inc. I Dorn, P., L.Johnson and C. Darby. 1979. The swimmingperformance of nine ta:ra I of commonCalifornia inshorefishes. Trans.Am. Fish.Soc. 108: 366-372. I D- 14 T I I I Fry, F.E.J. and E.T. Cox. 1970. A relation of size to swimmingin rainbow trout. ,r. I Fish. ResBd. Canada2T: 976-978. I Hanson, c.H., J.R. white and H.w. Li. 1977. Entrapment and impingement of t fishes by power plant cooling-waterintakes: an overview. Mar. Fish. Rev. 39(10):7-17. t Hartwell, I.A. and R.G. Otto. 1978. Swimmingperformance of juvenile menhaden I (Brevooniatyrannus). Trans.Am. Fish. Soc. 107: 793-798. I Hunter, J.R. and J.R.Zweifel. 1971..Swimming speed, tail beat frequency,tail beat t amplitude and size in jackmackrel,Trachurus symmetricus, and other fishes. U.S. Fish.Bull. 69: 253-266. I I-arson, L.E. 1979. Flow into offshore intake structures. Southern California I EdisonRes. Dev. Report 79-RD-65. Jrily L979. I Lindsay, c.c. 1978. Form, function and locomotory habits in fish. In: Fkh I Physiologt, Volume WI, Locomotion. W.S. Hoar and D.J. Randall, eds. T AcademicPress. New York. MRC. 1988a. Interim Technical Report 3. Midwater and benthic fish. Report I submittedto the California CoastalCommission. I MRC. 1988b. Interim TechnicalReport 5. Fish larvae and eggs. Report submitted t to the California CoastalCommission. I D-15 I l I MRC. 1989. Final TechnicalReport C. Entrapment of Juvenile and Adult Fish at SONGS. Report to the CaliforniaCoastal Commission. t Schuler,V.J. and L.E. Larson. L975. Improved fish protection at intake systems.,L I Environ Engin.Div., ASCE 101: 897-910. I Turnpenny, A.W.H. 1983. Swimming performance of juvenile sprat, Sprattus T sprattusL., and herring, Clupeaharengus L., at different salinities. J. Fish. Biol.Z3: 32L-325. I Turnpenny,A.W.H. and R.N. Bamber. 1983. The critical swimmingspeed of the t sand smelt (Atheina presbyterCuvier) in relation to capture at a power l stationcooling water intake. J. Fish.Biol.Z3: 65-73. I Van Olst, J.C. and J.R. Hunter. 1970. Some aspectsof the organizationof fish schools.J. Fisll Res.Board Canada2l: 1225-1238. Wardle, C.S. 1975. Limit of fish swimmingspeed. Nature, London 255: 725-727. t I Wardle, C.S. 1977. Effects of size on the swimmingspeeds of fish. In: ScaleEffects inAnimal Locomotion T.J. Pedley,ed. AcademicPress,I-ondon. I Webb, P.W. t975. Hydrodynamicsand energeticsof fish propulsion. Bull. Fish. I Res.Board Canada 190: 1-158. t I D- 16 T I I I TABLE D.1. Entrapment Rates, Probabilities of Avoiding Entrapment, and Adult Equivalent Losses. I ---- QUEENFISH I CRMcALLENGTH AVAII.A,BILTTY FUNCTIONS AVERAGE JUVEMLE ENTRAPMENT RATE HIGH AVERAGE Low I 3 0.0001302 0.0001271 0.0001239 4 0.0002361 0.ffi02n9 0.0002L97 5 0.0003353 0.0003187 0.0003020 t 6 o.N04n8 0.0003993 0.m03708 FRACTION AVOIDING ENTRAPMENT (ALL STAGES) HIGH AVERAGE Low I 3 0.9098 0.9106 0.9Lr4 4 0.8824 0.8845 0.8866 5 0.857s 0.8616 0.8658 I 6 0.8349 0.8418 0.8487 PERCENT ADULT EQUIVALENT LOSS HIGH AVERAGE Low I 3 9.02 8.94 8.86 4 TI.76 11.55 tL.y 5 14.25 L3.U 13.42 I 6 16.51 t5.82 15.13 I WHITE CROAKER CRmcALLENGTH AVAII.ABILITY FUNCTIONS t AVERAGE JUVEMLE ENTRAPMENT RATE HIGH AVERAGE Low 3 0.0000552 0.0000538 0.0000524 I 4 0.000L148 0.0001098 0.0001047 5 0.0001835 0.0001725 0.0001615 I 6 0.0002612 0.0002421. 0.0M2229 FRACTION AVOIDING ENTRAPMENT (ALL STAGES) HIGH AVERAGE Low 3 0.947L 0.9475 0.9478 I 4 0.9317 0.9330 0.9y3 5 0.9L42 0.9L70 0.9198 t 6 0.89,4 0.8996 0.9M3 PERCENTADULT EQUIVALENT LOSS HIGH AVERAGE Low 3 5.29 5.25 5.22 T 4 6.83 6.70 6.57 5 8.58 8.30 8.02 I 6 r0.52 10.04 9.57 l D-17 t I I I I t I t This pageintentionally left blank. I I I t I I I l I l D- 18 I I APPENDIX E I ESTIMATING DURATION AT RISK FOR PLANKTONIC STAGES l We estimate the length of time (duration) a larval stage is at risk to T entrapment by dividing the range in body length of larvae in a stage by the daily I growth rate. t E.l Estimating Range in Body Length of a Stage I Ideally we would estimate range in body length of a stage by subtracting estimatesof initial mean length at the beginningof a stagefrom mean length at end I of a stage. Here, the final length for a stage;would be the initial length of stage111. Unfortunately, it was difficult to estimate initial and final lengths of each stage I becausethe distribution of lengthsoverlap for adjacentstages. l We choseto usemodal lengths to estimatethe lengthof a stage:we estimate I the range in length of stage;by subtractingthe modal length of stage;from the modal length of the subsequentstager+r. In the case of the yolksac stage,we I subtractlength at first hatchingfrom the modal length of the preflexion stage. For I the post-flexionstage, we subtractthe modal lengthof post-flexionfrom the length at metamorphosis. Estimatesof lengthsat hatching and metamorphosisare taken, I or derived,from the literature (Table E.lA). I t I E- 1 I T I Sincemodal lengthsprobably overestimateinitial length,the tendencywould have been to overestimatethe range in length at stage for preflexion stage and t underestimatethe samefor post-flexionstage. I Since the length distribution for stagesoverlap, we encounter an additional t problem in that the modal length for a stageis sometimesvery close (or the same) to the modal length of an adjacentstage. While this tendsto decreasethe estimate t of length at stage for the subsequentstage, the overall range in length, from hatching to metamorphosis,is unaffected. In general, similar modal lengths t occurredfor earlier stages,which had shorter rangesthan later stages. The overall effect of closenessof modal lengths for adjacent stageson estimates of adult- i equivalentloss is slight and is discussedby taxon in RESULTS. If there are multiple I modesper stage,we choosethe modefor the shortestlength. I E.2 GrowthRate I For most taxa,we obtain estimatesof growth rate from the literature, Table I E.18. For ta,xawithout documentedestimates of growth rate, we choose0.25 mm/day, a mean rate (based on data in Table E.1A) characteristic of t microcarnivorousfish larvae. I E.3 Duration in Time at Stage I We estimateduration of eachstage by dividing the rangein length at stageby I daily growth rate (Table E.2). Here, we assumethat growth rate is linear for larval stages. This was demonstratedby MEC's data on queenfish and white croaker t E-2 l I I I (Barnettet al.1980) and publisheddata on northernanchovy (Methot and Kramer I 1979) and sardines (I-asker L964). For eggswe use a duration of 2.5 days, the averageembryonic period of small, pelagic fish eggs at t6 Cp (W. Watson,pers. l comm.). I I I t I I I I I I t t I l E-3 l REFERENCES l I Ahlstrom,E.H., K. Amaoka,D. A. Hensley,H. G. Moser and B. Y. sumida. 1984. Pleuronectiformes:development. In: Ontogenyand Systematicsof Fishes. t Allen Press,Inc., I-awrence, KS. H.G. Moser,ed. pp. 640-670. t Allen, L. G. 1979. I-awal developmentof Gobiesoxrhessodon (Gobiesocidae) with noteson the lawa of.Rimicola muscarum. t u.s. Fish.Bull. 77(7): 300-304. t Allen, L. G. Pers.comm., August 1985. I Barnett,A., E.E. DeMartini, D. Goodman,R. Larson,P. D. Seticand w. watson. 1980. Predicted larval fish losses to SONGS Units 1,, 2, and 3 and t preliminary estimatesof the lossesin terms of equivalentforage fish. Report I submittedto the Marine Review Committee,April 22, 1980. 34 pp. In: Report of the Marine Review Committee to the California Coastal I Commission: Predictionsof the effects of San Onofre Nuclear Generating Station and recommendations.Part I: Recommendations,predictions, and t rationale. MRC Document 80-04(1), Appendix 4 of TechnicalAppendices - Fish. J I Bolin, R. L. 1936. Embryonic and early larval stagesof the California anchovy, Engraulismordax Girard. Calif. FishGame22: 314-321,. I Brothers, E. B. 7975. The comparativeecologt and behavior of three sympatic I Califumiagobies. Ph.D. dissertation,Univ. Calif., SanDiego. E-4 I I Budd, P. L. 1940. Development of the eggsand larvae of six California fishes. I Calif. Dept. Fish Game,Fislt. Bull. 56: 1-50. l Butler, J. L., G. S. Hageman, H. G. Moser and L. E. Nordgren. 1982. t Developmental stages of three California sea basses(Paralabrax, Pisces, Serranidae). t CaICOFI Rept. 23: 252-268. Ehrlich. K. F. and D. A. Farris. 1.971..Some influencesof temperatureon the ,| development of the grunion Leuresthestenuis (Ayres). CaW Fish Game I 57(1): s8-68. t Ehrlich, K. F. and D. A. Farris. 1972. Some influencesof temperatureon the rearing of the grunion Leurestlrcstenuis, an atherine fish. Mar. Biol.12: 267- t 27t. I Farris, D. A. 1959. A changein the early growth rates of four larval marine fishes. I Limnol. Oceanogr"4: 29-36. I Fry, D. H., Jr. 1936. A descriptionof the eggsand larvae of the Pacific mackerel I (Pneumatophorusdiego). Calif. FishGame 22: 27-29. Hubbs, C. L965. Developmentaltemperature tolerance and rates of four southern t California fishes,Fundulus parvipinnis, Atheinops affinis, Leuresthestenuis, ,t and Hypsoblenniussp. Calif. Fish Game 51.: 113-122. I Hunter, J. R. SouthwestFisheries Center, NMFS. Pers.comm., August 1985. T E-5 I t t, Hunter, J. R. 1976. Culture and growth of northern anchovy,Engraulis mordax, larvae. U.S.Fish. Bull.74: 81-88. T Hunter, J. R. and C. A. Kimbrell. 1980. Early life history of Pacific mackerel, 1 Scomberjaponicus. U.S. Fislt.Bull. 78: 89-101. t Kramer, D. 1960. Development of eggs and larvae of Pacific mackerel and T distribution and abundanceof larvae 1952-56.U.S. Fish.Bull. 60(L74): 393- 438. t I-asker, R. 1964. An experimental study of the effect of temperature on the I incubation time, development,and growth of Pacific sardine embryos in I larvae. CopeiaZ: 399-405. T Lasker, R. and P. E. Smith. L977. Estimation of the effects of environmental variations on the eggsand larvae of the northern anchovy. CaICOFI Rept. t 19:128-137. t Methot, R. D., Jr. 1983. Seasonalvariation in survivalof larval northern anchovy, T Engraulismordatc, estimated from the distribution of juveniles. U.S. Fish. Bull.81.: 741-750. I Methot, R. D., Jr. and D. Kramer. 1979. Growth of northern anchovy,Engraulis I mordm,larvaein the sea. U.S.Fish Bull.77: 413-423. I E-6 T t I I Moffat, N. M. and D. A. Thomson. 7978. Tidal influence on the evolution of egg I sizein grunions(Leuresthes, Atherinidae). Environ.Biol. Fish.3(3):267-273. I Moser,H. G. SouthwestFisheries Center, NMFS. Pers.comm., August 1985. I Ninos, M. 1984. Settlementand metamorphosisin HypsoblenniusPisces, Blenniidae). t Ph.D.dissertation, IJniversity of SouthernCalifornia. ll Smith, P. E. 1985. Year-classstrength and survival of 0-group clupeoids. Can I. t Fish.Aquat. Sci.42: 69-82. $ Smith, P. E. and R. [,asker. 1978. Position of larval fish in an ecosystem.Rapp. P. -v. t Cons.Int. Explor.Mer 173: 77-84. Stephens,J. S. Jr., R. K. Johnson,G. S. Key and J. E. McCosker. 07A. The I comparativeecology of three sympatricspecies of California blennies of the I genusHypsoblennius Gill (Teleostei,Blenniidae). Ecol. Monogr. 40: 213-233. t Stepien,C. A. 1986. Life history and larval developmentof the giant kelpfish, I HeterostichusrostratusGirard. 1854. U.S.Fish. Bull.84: 809-826. T Stepien,C. A. Pers.comm., April 1986. I T E-7 I I t Stevens,E. G. and H. G. Moser. 1982. Observationson the earlylife historyof the mussel blenny, Hypsoblenniusjenkinsi, and the bay blenny, Hypsoblennius t gentilis,from specimensreared in the laboratory. CaICOFI Rept. 23: 269- 275. t I Sumida,B. Y., E. H. Ahlstromand H. G. Moser. 1978.Early developmentof seven flatfishesof the easternNorth Pacificwith heavilypigmented larvae (Pisces, t Pleuronectiformes).U.S. Fkh Bull. 77(1): 105-145. t Walker, H. J. Marine Ecological Consultantsof SouthernCalifornia, Inc. Unpubl. ms.(1980). I t Watson, W. 1982. Development of eggs and larvae of the white croaker, Genyonemuslineatus Ayres (Pisces:Sciaenidae), off the Southern California T coast. U.S.Fish. Bull.80(3): 403-417. t Watson, W. Marine Ecological Consultantsof Southern California, Inc. Pers. comm.,August 1985. I T White, B. N., R. J. l.avenbergand G. E. McGowen. 1984. Atheriniformes: developmentand relationships. In: Ontogenyand systematicsof fuhes. Allen I Press,Inc.,Lawrence, KS. H.G. Moser,ed. pp. 355-362. I Zweifel,J. R. and R. I-asker. 1976. Prehatchand posthatchgrowth of fishes- a I generalmodel. U.S.Fish. Buil.7aQ): 609-621.. t E-8 T T TABLE E.IA. 1), Data summary for length-at-hatching(in mm), growth rate (mm auy and length and age (in days, posthatching) at metamorphosis taxa of larval fishes at risk to SONGS' intake. References in I Table E.18. t LENGTHAT GRowm ME-[AMoRPHosIS SPECIESoRTAxoN llercntNc RATE AGE LENGTH t Arrow goby 3.0 0.?5c 43f L4.ge --c Black croaker L7a o.25c ))' < 15.5d t Blenny (unid.) 2-5,2.9,3.0 0.29 6 22.r California clingfish 4.0 0.?5c 24f 8-12 t California corbina r.7 0.?5c 49f a I Length-at-hatching estimated as the observed averageminimum length of the species' yolksac larva (or the L average minimum length of its preflexion larva, if the yolksac stage is completed prior to hatching). " Growth rate linearly interpolated, based on length-at-hatching length- at-metamorphosis, and duration of I larval stage. Growth rite characterizedbythe mean rate (0.25 mm day-l) of micro- carnivorous fish larvae u! Length-at-metamorphosis estimated as length of smallest known specimen that is fully scaled (or largest known specimen that is incompletely scaled). t^ Length-at-metamorphosis estimated as length of smallest known benthic recruit. E-9 TABLE E.18. References for data on length-at-hatching, growth rate, and length and age at metamorphosis, summarized in Table E.lA. SPEcIESoRTAxoN LITERATURE AND OTHER SoU RCES Arrow goby Brothers 1975 Black croaker H.G. Moser,pers. comnt.i W. Watson,pers.comm. Blenny(unid.) Hubbs1965; Ninos L984; Stephens et a|.1970;Stevens & Moser1982 California clingfish Allen 1979;L.G. Allen,pers.conun. California corbina H.G. Moser,pers. conrrn., W. Watson,pers.conrnr. California grunion Ehrlich & Farris L97L,L972;Moffat & Thomson1978; W. Watson,pers.cotrrtrr.; White et al.1984 California halibut Ahlstrom et al. L984;J.R. Hunter,pers. comnL Cheekspotgoby Brothers1"975 Pacificmackerel Fry L936;J.R. Hunter,pers. connt.; Hunter & Kimbrell 1980; Kramer 196QZweifel & Lasker1976 Diamondturbot Ahlstromet al.1984;Sumida et al. L978 Giant kelpfish Stepien1986 Hornyheadturbot Ahlstrom et al.1984;Budd 1940;Farris 1959;Sumida et al. L978 Jacksmelt W. Watson,pers.corn,lr.;White et aI.1984 Kelp & barred sandbass Butler et al.1982;H.G. Moser,pers. comm. Kelpfish(unid.) C. Stepien,pers.comnl I Northern anchovy Bolin 1936;Hunter 1976;Lasker & Smith1977; Methot 1983; Methot& Kramer1979; Smith L985; Smith & LaskerL978; t Zweifel & Lasker1976 Queenfish H.J, Walker,unpubl.; W. Watson,pers,conun. Reef finspot J.S.Stephens, pers. corntn. Salema W. Watson,penr.comrn. Shadowgoby Brothers1975 Spotfincroaker H.G. Moser,pers. cotrt,tr.; W. Watson,pers.comm. White croaker H.J.Walker, unpubl.; Watson 1982; Watson,pers. co,rrm. E-10 T I TABLE E.2. nsti-atea duration (in days) of stage, computed by dividing the range in body length in a stage by the daily growth rate. Range in length is computed by subtracting the modal length at stage from modal I length at subsequentstage. t TaxaWrrosEJUVEMLES MoDAL RANGEIN DURATION GRowTH AREETflRAPPED LENGI}I LENGTH T MM/DAY I Black croaker egg 2.5 0.25 yolksac L.7 03 L.2 preflexion 2.0 3.5 14.o I flexion 5.5 1.5 6.0 post-flexion 7.0 8.5 34.0 I metamorphosis 15.5 Calif. corbina egg 2.5 0.25 yolksac 1..7 1.3 5.2 preflexion 3.0 1.0 4.0 I flexion 4.0 2.0 8.0 post-flexion 6.0 ,.: 3r._6 t metamorphosis 13.9 Calif. grunion yolksac 5.6 0.9 3.0 0.30 preflexion 6.5 2.5 8.3 flexion 9.0 3.5 tl_.7 I post-flexion 12.5 '.' 18.3 metamorphosis L8.0 I Jacksmelt yolksac 5.0 2.0 8.0 0.25 preflexion 7.0 3.0 L2.O flexion 10.0 4.5 18.0 post-flexion 14.5 ,: to:o T metamorphosis 17.0 Kelp & barred egg 2.5 0.30 I sandbass yolksac 2-2 0.8 )1 preflexion 3.0 1.5 5.0 flexion 4.5 1.5 5.0 post-flexion 6.0 ,:t tt: metamorphosis 11.5 N. anchovy egg 2.5 0.30 I yolksac 2.8 0.3 0.8 preflexion 3.0 7.0 23.3 flexion 10.0 5.0 L6.7 ,l post-flexion 15.0 ?n.0 ffi.7 metamorphosis 35.0 I I E-11 I t TABLE E.2. (Continued) I TAXA WHosE JUVEMLEs MoDAL RANGEIN DURATIoN GRowTH AREENTRAPPED t LENGTH LENGTI] T MM/DAY Queenfish egg 2.5 0.?5 T yolksac i.t o.t 2.0 preflexion 2.0 4.0 16.0 flexion 6.0 3.0 L2.0 t post-flexion 9.0 tt:o *: metamorphosis 2,0.0 Salema egg 2.5 0.25 T yolksac 2-.0 2.0 8.0 preflexion 4.0 0.5 2.0 flexion 4.5 2.0 8.0 T post-flexion 6.5 n:o 36.0 metamorphosis 15.5 Spotfincroaker egg 2.5 0.25 t yolksac L.7 0.3 t.2 preflexion 2.0 2.5 10.0 flexion 4.5 2.7 10.8 t post-flexion 7.2 u: ,t: metamorphosis 13.5 White croaker egg 2.5 0.20 I yolksac 1.6 0.4 2.0 preflexion 2.0 4.0 20.0 flexion 6.0 2.0 10.0 t post-flexion 8.0 1r..0 55.0 metamorphosis 19.0 t I TAXAWHoSEJWEMLES MoDAL RANGEIN DURATIoN GRowTH ARENoTENTRAPPED LENGTH LENGl'H T MM/DAY Arrow goby preflexion 3.0 ?.0 8.0 0.25 flexion 5.0 2.5 10.0 post-flexion 7.5 ,: 2e:6 t metamorphosis t4.9 Blenny(unid.) preflexion )< 2.5 8.6 0.29 t flexion 5.0 8.5 29.3 post-flexion 13.5 8.6 29.7 metamorphosis 22.r I E-12 I I T I TABLE E.2. (Continued) I TAXAWHosnJuveNLEs MoDAL TTANGEIN DURATToN GRowrH t ARENOTENIRAPPED LnNcrH LENGTH T MM/DAY Calif. clingfish yolksac 4.0 0.0 0.0 4.25 preflexion 4.0 3.0 t2.0 t flexion 7.0 2.0 8.0 post-flexion 9.0 t:o o-o metamorphosis 10.0 t Calif. halibut egg 2.5 0.24 yolksac 2.0 0.5 2.1. preflexion ')< 3.0 12.5 I flexion 5.5 2.0 8.3 post-flexion 7.5 t:o o: metamorphosis 8.5 I Cheekspotgoby preflexion 3.5 2.0 8.0 0.25 flexion 5.5 1.0 4.0 post-flexion 6.5 u: n.6 metamorphosis L3.4 Pacific mackerel egg 2.5 0.57 yolksac )', 0.3 0.5 I preflexion 2.5 2.5 4.4 flexion 5.0 2.5 4.4 post-fledon 7.5 ,t: t metamorphosis t9.6 ": Diamondturbot egg 2.5 0.25 yolksac L.7 0.3 L.2 t preflexion 2.0 2.0 8.0 flexion 4.0 r..5 6.0 post-flexion 5.5 t:t t metamorphosis 11.0 ": Giant kelpfish preflexion 5.5 1.5 4.L 0.37 t flexion 7.0 2.4 5.4 post-flexion 9.0 ,o: *: metamorphosis 33.5 T Hornyhead egg 2.5 0.10 turbot yolksac L.5 1.0 10.0 preflexion 2.5 2.5 25.0 I flexion 5.0 2.5 25.0 post-flexion 7.5 4.5 45.0 t metamorphosis 12.0 E-13 t TABLE E.2. (Continued) T TAXA WHoSEJUVEMLES MODAL RANGE IN DURATIoN GRowTTt ARENOTENTRAPPED LENGTH T rrlu/oav I Kelpfish(unid.) preflexion 4.5 2.0 8.0 T flexion 6.5 1.5 6.0 post-flexion 8.0 *: tt:o metamorphosis 22.5 I Reef finspot preflexion 4.0 1..5 6.0 0.25 flexion 5.5 1.0 4.0 post-flexion 6.5 to:t or: T metamorphosis L7.0 Shadowgoby preflexion 3.5 2.4 8.0 0.25 I flexion 5.5 0.0 0.0 post-flexion 5.5 4.0 r.6.0 metamorphosis 9.5 I t t I t I I I E-T4 3eO1 Hanson H Fload, Box 4P1O Georgetown, CA S5634 ls16l 333-4OQl 30 May 1989 to: MRC Members fr: KeithParker W sub3:- Ad.dend.umto ltRC 1988d, Tech. Report: Adult-Eguivalent Loss Pleaseattach this to Final Technical Report on Adult Equivalent Loss (MRC 19B8d). The following thought occurred to me as I reviewed the MRC's repoft on adult- equivalent loss to thE CCC: I may have underestimatedadult equivalent toss fbr the juvenile stagesof queenfish and white cr6aker (MRC 19SSd). As explained in our Appendix D, we used an e-xponentiaifunction to model the relationship of entrapment rate ofjuveniles. An attached figure shows an exponential function and a linear functlion for juvenilL queenfish - the figure f_6rwhite croaker would look similar. As I look at this figure, itieems to foiethat the expori'entialfunction gives an unrealistically low estimate of enirapment rate: it's hard to im-aginethat the rate decreasesso quickly fiom the post-flexion stag6. Contrast this is to the linelr function. I suspectthat for early'juveniles- tLe Hnear function gives a more realistic estimate of entrapment rate than th-e exponential function. For- older juveniles, the exponential functioin may be more realistic. i tfrint The true shape of the function probably looks sigmoid, being relatively flat on both ends,with the steep6stchange in entrap'mentrdte takingllace someihere near the center of -percentagJpointjuvenile age. Thd mean oT the expoiential and lineiri functions probably differs only a or two from that of d sigmoidalfunction. For the juvenile stageonly, here are estimatesof entrapment rate and adult-equivalent loss (AEL) for exponentiafand iiirear functions, as well as their mean. Exponential iates are the same as those glven by Parker and DeMartini (MRC 1988d). I computed mean adult- equivalentlosses onmean entrapmentrates. Queenfish: -Exoonential Linear Mean Ent. Rate 2.0Lx10* 5. o8xLo4 3.55;r.IF AEL 5.62 t_3.6? 9.72 White Croaker: Exponentia! Linear Mear} Ent. Rate 5.60xL0-) 2.51xTo? L.64' AEL 1.84 6.92 4.L82 The total adult equivalentlosses for planktonic and juvenile stagescombined are Total AEL Exponential Linear Mean Queenfish L0.9? L8.42 L4.72 White Croaker 5.62 L0.5Z 8. L? In Section3.3 (URC 1988d)we computedlosses in numbersand biomassof the adult standing stock by multiplyrng the percent total adult-equivalent loss times the estimated standingstock. For exponential,line-ar and meanrates thes-e are Biomass(MT) Exoonential Linear Mean Queenfish 47L 799 535 White Croaker 295 553 424 Numbersof Fish -Exoonential Mean Queenfish 1. 5x10/ 2. o;io7 White Croakeir 3.1x106 4.5xL06 Biomassand numbersfor the e4ponentialrate are the sameas in MRC (19S8d). For queenfishand white croakerthe estimatedadult-equivalent losses can arzuablvbe as.h-ighas.L8.4Vo,and 10.5V-o respectively (based on the linearfunction). This wouli puf the {qlt equivalegt loss for_all power planls in the bight at approximately nvice these vi.lues - 37Vo and ZlVo. The . MRC might want to pre-sent ptissimistic (linear) and optimistic (exponential)estimates in its report on adult equivalentst6 the ccc. Reference MRC. 1988d.Technical Reporr: Adult-Equivalent[,oss. TEL l'to. Mag 2,89 7 |45 P.04 f ntropmeni [totes JuvcniieQue*rrfislr Lincor & frponcntiol Funar.iorrs o.o0l I t:.o.001 0,0009 0.0008 9 0.0007- o t o.0(,ttb o :,:.t ,..-a 0.000$ !J 0.0004 [,.OUUJ 0.0uu'.. -\.- ? \-_-__-*-_--r-___+ 'r- 0.001JI \_ slr -:_ --)= -r-..'"t'll-= i FA 160 2e1 O:ry:r in Jr.'cnilc Strrqc Lir's:r r Cxgorrcn',inl