CLAM-OYSTBR-ABALONECLAN-OYSTER-ABALONE LARVAL REARING

ANNUAL REPORT July 1,l~ 1970 to June 30,30, 19711971

Gerald T. LukasLukas Gary G. Gibson Fish Commission of Oregon

U.S. Department of Commerce National Oceanic and Atmospheric Administration National Marine Fisheries Service Commercial Fisheries Research and Development Act Subproject l-60-R-1l-60-R-l Contract No. 14-17-0001-2329

July 19711971 TABLE OF CONTENTS

Page No.No.

INTRODUCTION.INTRODUCTION 1

CLAM STUDIES.STUDIES . 1

Methods • • • • • • • • 1 Spawning and Larval Rearing ofof ClamsClams .• 1 Field Studies Studies • . • ...... • . • . . 2 Manila littlenecklittleneck clamsclams ...... • . . . . . • . . 2 Native littleneck clams •...... 2 Gaperclams...... Gaper clams • . . 2 Butter clams clams •....•...... 2

ResulResultsts ...... , . . , ...... 2 Spawning and and Larval Larval Rearina Rearing of Clams of Clams••...... 2 FieFieldId Studies ...... • . • • • . . 3 Manila Ii ttlenecklittleneck clams clams• ...... 3 Native littlenecklittleneck clamsclams ...... • . 3 Gaperclams...... Gaper clams . • . . • . . . S5 ButterButterClams Clams •.••...... 5 Discussion andand Conclusions 6 Spawning and and Larval Larval Rearing Rearing of Clams. of Clams ...... 6 FieldFieldStudies Studies • • • •...... • • •• • • 6 Manila littleneck littleneck clams clams...... 6 Native littleneck littleneck clams clams• ...... 6 Gaperclams...... Gaper clams • . 7 Butterclams...... Butter clams. . 7

OYSTEROYSTERSTUDIES STUDIES. • • • •...... 7

MethodsMe thod.s . • ...... 7 Spawning and and Larval Larval Rearina Rearing of Clams. of Clams ...... 7 FjejdStudjesField Studies • . • ...... • . • • • 7 Imported vs. vs. Laboratory-Reared Laboratory-Reared Spat Spat...... 7 Tray CultureCulture at atDifferent Different Depths. Depths ...... 8 String vs. vs. Tray Tray Culture Culture ...... 8 Winter Spat Spat Survival Survival •••..••• ...... 8 ResulResults...... ts ...... 9 Field Studies Studies . . • ...... • . • . • . • 9 Imported vs. vs. Laboratory-Reared Laboratory-Reared Spat Spat...... 9 Tray CultureCulture at atDifferent Different Depths Depths ...... 10 String vs. vs. Tray Tray Culture Culture ...... 10 Winter Spat Spat Survival Survival .••••.•...... 11 Discussion and andConclusions Conclusions .•.••..••.••...... 12 FieFieldStudies Id Studies . • • • ...... • • • • . . • . . • . • . • • 12 Imported vs. vs. Laboratory-Reared Laboratory-Reared Spat Spat...•...... 12 Tray CultureCulture at atDifferent Different Depths Depths ...... 13 String vs. vs. Tray Tray Culture Culture ...... 13 Winter Spat Spat Survival. Survival ...... 14

ABALONESTUDIESABALONE STUDIES . • ...... 14

Methods ...... 14 ResultsResults...... •. 15 Discussion.Discussion ...... 15 PROGRESS TOWARD OBJECTIVES.OBJECTIVES...... 15 LITERATURE CITED. CITED• . • ...... 16 LIST OF TABLES

Table No.No. Page No.

1 Mean Shell LengthLength andand PercentagePercentage SurvivalSurvival ofof Ilanila HanUa Clams PlantedPlanted in in an an Experimental Experimental Clam Clam Bed. Bed...... • • . 4

2 Growth and Percentage Survival of NativeNativ.e LittleneckLittleneck Clams 7 7Months Months After After Planting. Planting • ...... • • • • • 4

3 Growth and Percentage Survival of ButterButter ClamsClams atat 15 andand 24 24 {\ionths Months After After Plan tingPlanting • ...... • • . 5

4 Length and Width (mm)(mm) and Volume of Imported and Hatchery-Reared Pacific Pacific Oysters Oysters •....•••• ...... 9

5 Length and Width (mm)(mm) of ImportedImported andand Hatchery-Hatchery­ Reared Kumamoto Kumamoto Oysters Oysters ....•...... 10

6 Shell Growth (Length(Length Width mm)II1II) ofof PacificPacific OystersOysters Reared in Suspended Trays, in a Stationary Intertidal TrayTray...... , ...... 10

7 Shell Growth (mm)(mm) of Pacific Oysters Cultured on Strings (Rack(Rack andand BoomBoom Log)Log) andand inin aa SuspendedSuspended Tray.Tray. 11

8 Winter Survival of Laboratory-Reared Pacific Oyster Spat Planted at Different Ages and Times in Yaquina Bay (Sampled(Sampled April April 1971) 1971). • . • ...... • • • • • • • . • • 11

LIST OF FIGURES

FisureFigure 11o.No. Page No.

1 Mean Shell Size (Length(Length Times Width) vs.VS. Meat Volume (Shucked(Shucked Count Per Quart) of FourFour Groups ofofPacificOysters Pacific Oysters ...... • . • . . . • • • . • 12

2 Mean Shell Size (Length(Length Times Width) vs. Meat Volume (Shucked(Shucked CountCount PerPer Pint)Pint) ofof ThreeThree GroupsGroups of KumomotoKumomoto Oysters Oysters ..•...... •....• ...... 13 CLAM-OYSTER-ABALONECLAI.1-OYSTER-ABALONE LARVALLARVAL REARINGREARING

INTRODUcrION

Clam studies in the laboratory during the 1970-71 project year con­con-

tinued with the spawning andand larvallarval rearingrearing ofof severalseveral species.species. FieFieldld

studies were initiated utilizing laboratory-rearedlaboratory-reared juvenilejuvenile clams.clams. These

clams werewere plantedplanted inin experimentalexperimental plotsplots andand monitoredmonitored forfor growthgrowth andand

survival. Monitoring continued on experimental clam plot studies initiated

during the previous report period.

Field studies comparing growth and survival of laboratory-reared and

imported Pacific and Kumamoto oysters were completed.completed. We continuedcontinued studies

comparing various methods of oyster cultureculture inin YaquinaYaquina Bay.Bay. Winter sur-sur­

vival of laboratory-rearedlaboratory-reared oysteroyster spatspat waswas determined.determined.

AdultAdul t redred abaloneabalone were obtainedobtained forfor spawningspawning purposes.purposes.

During the projectproject year~year, Duane Phibbs, the projectproject biologist,biologist, resigned

to go into private business. This resulted in some delay in project

activities.

CLAM STUDIES

Methods

Spawningpawning and Larval Rearing of Clams

Several clam species were spawned in the laboratory to provide juven-juven­ ile clams forfor fieldfield studies.studies. These included gaper (Treeue(TzoeSU8 capax),capaa:) ~ native

littleneck (Protothaca(Pxatothaca staminea),etaminea), and Manila littlenecklittleneck (Tapes 8elfli-semi­ deauseata)decussata) clclams.ants,

Razor clamsclams (SiUqua(Siliqua patula)patuZa) were induced to spawn by using KC1KCl and allowing the water to warm toto 17-1817-18 CC (Phibbs,(Phibbs, 1968).1968). Razor clam larvae were reared through metamorphsis and the resultant set placed in sand.

Untreated seasea water,water. drawndrawn fromfrom thethe bay,bay, waswas circulatedcirculated throughthrough thethe tank.tank. 2.

We attempted attempted to spawnspawn geoduckgeoduck (Panope generosa)generoea) clamsclams butbut thethe adultadult stock had spawned prior prior toto our collectingcollecting them. them.

Field StudiesStudies Manila littlenecklittleneck clams.clams. Juvenile Manila1anila littlenecklittleneck clams clams rearedreared inin the laboratorylaboratory andand plantedplanted in in IIay Hay 19701970 (Phibbs,(Phibbs ~ 1970)1970) werewere sampledsampled four times during thethe project year.year. These clams~clams, with with a~an averageaverage length ofof 3 nun, were were planted planted in in anan 88 byby 2S-foot25-foot plot inin upper upper YaquinaYaquina Bay at at a densidensityty of 2020 per square foot. Native littleneck clams.clams. In SeptemberSeptember 1970 1970 600 600 juvenile juvenile littleneck littleneck clams \~erewere planted planted inin preparedprepared clamclam beds beds containing containing several several typestypes of sub-sub­ strate. These laboratory-reared juvenilesjuveniles were were approximately approximately 11 11 monthsmonths old andand hadhad a meanmean shellshell lengthlength ofof 9.9 9.9 mm. mm. They were were planted planted at at thethe rate of 100100 perper plot inin 66 plotsplots each each measuringmeasuring 44 byby 44 feet. Five ofof the plots contained gravelgravel ofof variousvarious sizessizes mixed into into thethe substrate. One plotplot waswas left undisturbedl.mdisturbed and served asas a control. Gaper clams.clams. Three thousand juvenilejuvenile laboratory-rearedlaboratory-reared gaper gaper clams clams were plantedplanted in anan 88 byby 15-footIS-foot experimental experimental plotplot in in Yaquina Yaquina Bay. Bay. These clams averagedaveraged 13.613.6 mmnun shell shell length.length. They werewere plantedplanted inin Septnieber Septmeber 19701970 in anan areaarea whichwhich contained aa natural populationpopulation ofof adultadult gaper gaper clams. clams. Butter clams.clanlS. Monitoring of of growthgrowth and and survival survival ofof butter clamsclams planted inin preparedprepared plotsplots in in Yaquina Yaquina Bay Bay continued.continued. These laboratory­laboratory- reared juvenilejuvenile clams clams werewere plantedplanted in in December December 19681968 (Phibbs,(Phibbs I 1969).1969).

ResultsResults Spawning and and LarvalLarval Rearing ofof ClamsClams Manila andand native native littleneck clams clams werewere successfullysuccessfully spawned sp81med and the resultant juvenilesjuveniles areare currentlycurrently beingbeing heldheld inin laboratorylaboratory tanks.tanks. The 3.

Manila juveniles will be planted in several bays which offer suitable habitat and will be monitored periodically to evaluate survival and grOt/thgrowth

in these selectedselected areas.areas.

The juvenilesjuveniles from the gaper clam spawning suffered high mortmortalitiesalities while being held in the laboratorylaboratory duedue toto lacklack ofof food.food.

The juvenile razor clams also experienced high mortalities while being held in the laboratory. Approximately 5 months after spawning only seven

juveniles survivedsurvived andand averagedaveraged 5.25.2 nun mm in length.length. The high mortalitiesmortalities experienced by the juveniles probablyprobably resulted from extremely low salinities

(2-4 0/00)o/oo) whichwhich occurred periodically during thethe 5-month5-month winterwinter period.period.

Before further attempts are made to rear razor clams, laboratory equipment will be designed which will monitor the salinity of the incoming water and automatically shut off the water when salinitysalinity decreasesdecreases toto criticalcritical levels.levels.

Field Studies

i'ianilaManila littleneck clams. The survival of the Manila littleneck clams in the experimental plots varied accordingaccording toto thethe typetype ofof substratesubstrate (Table(Table 1).1).

During the 12-monthl2-month period a river gravel substrate produced the best sur­sur- vival while gravel-mud substrate waswas poor.poor. A mudrod substrate resulted in total mortality afterafter onlyonly 33 months.months. The clams grew well through October

1970 butbut during the winter and spring period growthgrowth waswas curtailed.curtailed. However, the total growthgrowth ofof 18.418.4 umiDIll duringduring thethe yearyear the clams were in thethe plot isis believed to be aboveabove average.average.

Native littlenecklittleneck clams.clams. The juvenile littleneck clams planted in an artificial bedbed containing various types of substratesubstrate werewere sampledsampled for growth and survival 7 months after planting. The average length of all clams when sampled was 12.812.8 mm,mm, anan increaseincrease ofof 2.92.9 nunun in 7 months. There 4.

Table 1.1. Mean Shell Length and Percentage Survival of ManilaManila Clams Planted in an ExpArimentalExperimental Clam Bed

Mean Shell PercentasePercentage Survival Date SurpSampled led Length (mm)(mm) RiverRiver GravelGravel River Gravel-Mud Mud

8-18-70 12.012,0 12.5 10.0 0 10-28-70 19.1 12.5 15.0 0 1-7-71 19.6 7.5 2.5 0 5-14-71 21.4 4.6 0.8 0

were some differences in growth of clams between the different plots (Table

2). However, some of the plOtsplots yielded very few clams so average shell lengths of the samples may not reflect thethe actualactual averageaverage growth.growth.

Table 2.2. Growth and Percentage Survival of Native Littleneck Clams 7 ~1onthsMonths After Planting

Plot Substrate Mean Shell Percentage No. Type 111/ Length (mm)(mm) Survival

1 Control 12.5 2.0 (unchanged)

2 CrusheCrushed d Rock 12.6 42.0 3/4"-1 l/2'1/2"

3 River Rock 14.0 4.0 3/4" minus

4 Crushed Rock 13.0 6.0 3/4l3/4" minus

S5 River Rock 12.0 2.0 3/4"..l3/411 -1 1/21!1/2"

6 Crushed Rock 13.7 8.0 1 l/2"-3"1/2H-3"

Y1/ SubstrateSubstrate describeddesoribed byby PhibbePnibbs (1969).(1969) •

Only one type of substrate, 3/4-1 1/2 inch crushed gravel, had a significantly high survival rate.rate. One problem duringduring thethe 7-month7-month inter-inter­ val the clams were in the plots was the deposition of silt. The results are therefore probably not conclusiveconclusive asas clamsclams inin thethe variousvarious gravelgravel plotsplots 5. might have have shawn shcn better better survivalsurvival ifif thethe plotsplots werewere inin anan areaarea wherewhere sil­sil- tation hadhad notnot occurred.occurred. Gaper clams. The juvenile gapergaper clamsclams plantedplanted in in September September 1970 1970 werewere sampled 11 monthmonth later. later. No clamsclams couldcould be found.fomd. This planting waswas a second attemptattempt toto plantplant laboratory-rearedlaboratory-reared juvenilejuvenile gapergaper clams.clams. The pre­pre- vious attempt, made in in 19691969 (Phibbs, (Phibbs, 1969), 1969), also also resulted resulted inin a total mor- mor­ tality. The probable cause was prolongedprolonged exposureexposure duringduring low tidestides andand predators. The second plantingplanting was made in in anan area which containedcontained a natural populationpopulation ofof adult gapergaper clamsclams andand was was at at aa lowerlower tide tide level. The totaltotal mortalitymortality waswas believed toto havehave resultedresulted fromfrom predationpredation by crabs.crabs. Butter clams.clams. Juvenile butter clamsclams inin thethe experimental experimental plotsplots werewere sampled in DecemberDecember 1970.1970. They grewgrew an an average average of of 14.714.7 mmnun in in shell shell length in aa 9-month9-month periodperiod (Table(Table 3).

Table 3. Growth and and Percentage Percentage Survival Survival ofof Butter ClamsClams at 15 and 24 Months After After PlantingPlanting

March 25,!25, 19701970 December 9,9, 19701970 Plot Gravel TypeType t4eanMean ShellShell Percentage Mean ShellShell Percentage No. and Size Length (mm)(mm) Survival Length (mm)(nunl SurvivalSurviva1 1I Control 26.326,3 0.2 Y2/ 0.2 (unchanged)(mchanged) 2 Crushed 24.2 2.020 38.6 0.707 3/4"-1 1/2"l/2' 3 River 23.8 0.5 41.0 0.4 3/4U3/411 minusminus 4 Crushed 23.8 4.5 38.6 3.3 3/4"3/4'1 minusminus S5 River 23.3 0.9 35.6 0.707 3/4"-13/410 -1 1/2"1/2" 6 Crushed 22.2 2.4 38.2382 2.5 1.1 1/2"-3"1/2"-3' ------Total Plot Average 23.5 1.8 38.2 1.2

2/y SampleScvnpie broken~br'ken,, unmeasurabte.unmeasurable. 6.

Survival in plot number four waswas the highest of all plotsplots butbut mortal­mortal-

ity between March and DecemberDeceDber 19701970 inin plotplot fourfour waswas greatergreater thanthan thethe

average. Plot number six withwith the nextnext highesthighest survival rate did notnot

experience any mortality during the March toto DecemberDecember period.period. The increase

in survival in December was the result ofof samplesample variation.variation.

Discussion and ConclusionsConclusions

Spawning and Larval Rearing ofof ClamsClams

The continued success in laboratory rearing of native littleneckIittleneck and

Manila littleneck clams has been encouraging.encouraging. An adequate supply ofof thesethese

juveniles is needed for field studies to determine the bestbest sizesize and time

of year of planting for maximum survival.survival. Although stripping the sex

products from gaper clams has been successful, there is a greater chance

of obtaining malformed andand immatureimmature eggs.eggs. More work needs to be done on

the technique of inducing the adult gapers to spawn naturally. TheThe poorpoor

survival of juvenile razor clams was assumedassumed to have resulted from low

salinities which occurred duringduring winter.winter. Further attempts will be mademade

to rear razor clams and to mommonitortor the incoming waterwater and preventprevent exposureexposure

of the juveniles toto lowlow salinities.salinities.

Field Studies

iai1a~';~1~.~~_!!~t1eneck littleneck clanis. clams. The juvenile Manila clams have ShO\,ffishown good

growth during the year theythey were inin thethe experimentalexperimental plotplot inin upperupper YaquinaYaquina Bay.Bay.

The survival of 4.6% in the gravel substrate may be typical butbut no data are available for comparison.comparison. Additional fieldfield studiesstudies areare planned.planned.

Native littlenecklittleneck clams.clams. Juvenile littlenecklittleneck clamsclams shcMedshowed exceptional survival in the substrate consisting of 3/4-1 1/2 inch crushed rock probably because water current in this area kept the plot freefree of silt. Growth of 7.

2.9 nmJl1ll in 7 months is probably about averageaverage forfor aa winter period.period. Sur-Sur­ vival in the other plots might have beenbeen higher if silt deposition hadhad not occurred.

Gaper clams.clams. The planting of juvenilejuvenile gaper clams will be attempted again. Screen will be used toto covercover thethe clamclam plotplot toto keepkeep predatorpredator crabscrabs out.

Butter clams.clams. Juvenile butter clams continued to have the best sur­sur- vival in a plot containing l/4-inch3/4-inch minus crushed gravel whichwhich closely approximates natural habitat.habitat. Clams in crushed 1 1/2-3 inch gravel experi-experi­ enced good survival. These plots areare part of the same habitat study as the littleneckIittleneck clamclam study.study. Butter clam survival may have been affected by siltation, a factor that willwill bebe considered in futurefUture experimental clam plots.

OYSTER STUDIES

Methods

Spawning andand LarvalLarval Rearin.gRearing

Oyster spawning and larval rearing activitiesacdvities have been phased out of this program andand areare nnow being done on aa routine basis by Oregon State

UniversityUniversity personnel inin theirtheir pilotpilot oysteroyster hatcheryhatchery atat Newport.Newport.

Field Studies

I!'P0rtedImported vs. Laboratory-Reared Spat. The study comparing growth and survival of imported andand laboratory-rearedlaboratory-reared PacificPacific andand KumainotoKumamoto oysteroyster spat in Yaquina BayBay was completed.completed. In .MayMay 1969 spat of Pacific oysters spawned in June-August 19681968 andand spatspat fromfrom KumainotoKumamoto oysters spawnedspawned inin

September-December 1968 were placed in trays suspended from an oyster rearing raftraft inin YaquinaYaquina Bay.Bay. Imported Japanese seed was planted atat thethe 8. same$ mne time,time, place,p lace, andand inin thethe samesame manner. Random measurements (length(length and width of 40 oysters fromfrom each tray)tray) werewere takentaken atat plantingplanting andand peri-peri­ odically until DecentherDecember 19701970 whenwhen samplessamples ofof oysters were shucked toto determine oyster count per unitunit volume.volume. This was done to test whetherwhether shell length-width measurements accurately indicate oyster sizesize (meat volume). Survival was determineddetermined by grossgross examinationexamination ofof thethe cuitch.cultch.

Tray Culture at Different Depths.Depths. LabLaboratory-reared oratory-reared oystersoysters cultured off bottanbottom in a stationary intertidal tray, and in suspended trays at various depths (3, 6, 9, and l2-feet12-feet belowbelow the waterwater surface)surface) werewere monitoredmonitored for growth and survival. Random samples of oysters (length(length and widthwidth of

40 oysters fromfrom each tray)tray) were measuredmeasured everyevery 33 months.months. At 2121 months of age (June(June 1971) samples of oysters will be shuckedshucked toto determinedetermine meatmeat volume.volume.

String vs. Tray Culture. Growth and survival experiments with Pacific oyster spat (cultth(cultch separatedseparated byby 6-inch6-inch plastic pipepipe spacers)spacers) onon wirewire strings was continuedcontinued inin YaquinaYaquina Bay.Bay. Some of these 8-foot strings were suspended from a boom log; others were draped over a wooden rack. Additional spat of the same brood were suspendedsuspended fromfrom thethe oysteroyster raftraft inin aa tray.tray.

Quarterly samples were taken to compare growth and survival of those animals exposed by tidal fluctuations (rack(rack strings) and oysters continuously sub-sub­ merged (log(log boom strings andand trays).trays).

Winter Spat Survival. A study to determine winter survival of laboratory-reared oyster spat was completedcompleted inin YaquinaYaquina Bay.Bay. Four broods of oysteroyster spat,spat, setset inin August-OctoberAugust-October 1970 and in JanuaryJanuary 1971, werewere plantedplanted in a suspended tray at various ages from SeptemberSeptenber 1970 through February

1971 and counted in April 1971 toto determine survival.survival. 9.

Results Field StudiesStudies Imported vs.vs. Laboratory-RearedLaboratory-Reared Spat. MortMortalityality inin all groupsgroups of Pacific oystersoysters was was negligiblenegligible except except among among thosethose animals animals from from thethe August August spawning. August spat spat werewere collected collected on on scallop scallop shellsshells on whichwhich silt silt settled and and smothered smothered aboutabout 50%50% ofof the youngyoung oysters. After 1919 monthsmonths ofof growth,growth, hatchery andand imported Pacific Pacific oysters averaged thethe same both both in in shellshell sizesize and and in in meat meat volume volume (Table(Table 4).4). Hatchery oystelS oystefrxi from June's June's spawning spawning were thethe smallestsmallest inin shell sizesize andand meat volumevolume of of all all groupsgroups (highest(highest count perper quart). July's spawning spawning waswas .thethe largest.

TableTab Ie 4. Length and WidthWidth (mm)(mm) andand Volume of of Imported andand Hatchery-Reared PacificPacific OystersOysters Imported Month Hatchery SpawningS~awnini DateDate Spawnings§awnin~ DateDate Sampled 6-5-68 7-29-68 8-13-68 Summerummer 1968

May 1969 8-7 7-5 5-4 7-5 June 18-15 19-17 12-12 18-14 September 46-33 53-39 44-40 543454-34 December 61-52 66-48 61-44 67-48 March 19701970 65-45 71-48 62-54 73-51 ~1ayMay 72-54 81-57 75-66 85-60 SeptemberSepteJdJer 92-65 108-71 97-76 110-73 December 95-65 114-77 99-78 (Mean(Mean 113-72 103-73)103- 73) Shucked OysterOyster Count Per QuartQuart 40 26 30 (Mean(Mean 32)32) 32

After 2020 monthsmonths of growth,growth, importedimported KuniainotoKumamoto oysters oysters averagedaveraged slightly slightly smaller inin shellshell length length (4.5 (4.5 mm) nun) andand width width (5.5 (5.5 mm) mm) thanthan laboratorylaboratory progeny progeny but producedproduced a 9% greatergreater meatmeat volume (lowest (lowest countcount perper pint) (Table 5). MortMortalityality was negligiblenegligible in bothboth groups.groups. 10.

Table 5.5. Length and Width (mm)(mm) ofof ImportedImported andand Hatchery-Hatchery­ Reared Kumamoto Oysters

Imported Month Hatchery SpawningSEawnin& DateDate SEawnin&Spawning Date Sam:eSampled1ed 9-23-68 12-17-68 SummerStunner 19681968

April 1968 3-3 8-7 5-4 July 30-26 30-26 22-19 October 45-37 48-38 41-33 January 19701970 46-38 47-39 40-32 May 48-41 53-41 43-34 September 55-43 59-45 53-40 December 56-44 59-45 53-39

Shucked Oyster COWltCount Per Pint 91 90 82

Tray Culture atat DifferentDifferent Depths.De:eths. Shell growthgrowth ofof PacificPacific oystersoysters

19 monthsmonths after planting in Yaquina BayBay was better inin suspendedsuspended traystrays than in the stationary intertidal traytray (Table(Tab Ie 6).6). Growth in suspended trays waswas nearlynearly the same at all depths tested,tested. l-JortaliMortalityty in all of thethe trays was negligible.

Table 6.6. Shell GrowthGrowth (Lenth-Width(Length-Width nzii) nm) of Pacific Oysters Reared in Suspended Trays,Trays# in a Stationary IntertidalIntertidal Tray

Stationary SuspendedSusEended TrarTrayss (Depth)(De:ethl Intertidal Date 3 Feet 6 FeetFeet 9 Feet 12 Feet TrayTr!l

September 1969 2 2 2 2 2 October 9-7 10-9 9-8 9-8 6-5 December 15-13 18-16 16-14 17-15 -- January 1970 15-13 19-15 16-14 17-15 10-8 Marchr.1arch 19-16 23-19 23-20 27-22 15-13 JWleJune 42-34 42-32 44-35 48-37 27-23 September 69-52 67-50 73-51 73-47 57-47 December 80-56 77-57 81-53 83-58 60-43 April 1971 85-59 88-64 85-63 89-65 62-47

String vs. TrayTrar Culture. Shell growth, 1313 months afterafter planting,planting, was slightly better inin the suspendedsuspended traytray thanthan onon stringsstrings (Table(Table 7).7). Oysters on the rack string werewere the smallest of the three groups'tested.groups tested. 11.

Table 7.7. Shell Growth (mm)(mm) of Pacific Oysters Cultured on Strings (Rack(Rack. and Boom Log) and in a Suspended Tray

Date Rack.Rack Strings Boom Log1g StringsStrings Tray

3-70 3.5 3.5 3.5 7-70 18.2 27.3 29.3 11-70 45,145.1 61.1 60.3 1-71 51.3 60.9 53.6 4-71 58.1-44.5 65.4-44.2 67.1-51.6

Winter SpatSpat Survival.Survival. Mean overalloverall survivalsurvival ofof spatspat waswas 45%.45%. Sur­Sur- vival of tho August brood was 44%; SeptemerSeptember brood 31%; October brood

59%; January brood 60%.60%. Oyster spat survived better when planted during the months under study thanthan September,Septemer, December,December, andand JanuaryJanuary (Table(TabIe 8).8).

Table 8.8. Winter Survival of Laboratory-RearedLaboratory-Reared Pacific Oyster Spat Planted at Different Ages and Times in Yaquina Bay (Sampled April 1971)1971)

Age of Seed Survival Date Planted (Days) (%)(t)

9-30-70 12 19.0 54 13.0

11-4-70 29 55.3 47 59.0 89 70.7

12-4-70 59 50.0 77 2.5 119 37.2

1-5-70 91 46.5 109 17.9 151 32.5

2-11-71 35 60.1 128 85.0 146 57.1 188 65.8 12.

Discussion andand ConclusionsConclusions

Field Studies

Imported vs. Laboratory-RearedLaboratOry-Reared Spat. Because it isis more practical

to measure shell size than meat volume,volume, andand sincesince shuckingshucking ofof oystersoysters

precludes further measurement, wewe wantedwanted to determine if shellshell length

and width measurements accurately reflectreflect oysteroyster size.size. Mean shellshell

length times widthwidth gave a fairly accurate indicationindication ofof PacificPacific oysteroyster

size in meat volume (Figure 1); however,however, this relationship waswas notnot

apparent with KumainotoKumamoto oystersoysters (Figure 2). Length-width measurements

did not indicate meat volume for thisthis species.species. ICumnamotoKumamoto oysters oysters are

quite variable in shell depth (thickness),(thickness), dependingdepending onon physicalphysical conditions,conditions,

such as the degree of crowdingcrowding duringduring growth.growth. Less crowded conditions

in the tray containingcontaining importedimported IcumamotoKumamoto oystersoysters probablyprobably resulted inin

deeper oysters, hence thethe greatergreater volumevolume toto length-widthlength-width ratio.ratio. Thickness

is impossible to measuremeasure whilewhile oysters are clustered or attached to cultchcuitch

material.material •

8,

.p 7,000 tlO ~ . ...J 6,500

6,6,000.~____~:-__~~__-.~____~~__-,~__~ 20 Meat Volume

FigureFigere 1.I. Mean Shell Size (Length(Length Times Width) vs. Meat Volume (Shucked(Shucked CountCOlDlt Per Quart) of Four Groups of Pacific Oysters 13.

2,700 ... 2,600'1$' " " "­ • ~ 2,500 ~ " 5:: " -1"1 2,400 I­ " "­ ~ "­ • +J4.) "0 2,300 "­N -1"1 - 3: " ><> 2,200 - " "­ tl ~° 2,1002,100 ~ ""­ Q)4) ...:I • " 2,000 ... " N

1,900 I I I 1 " 1 80 82 84 86 88 90 92 Meat VolwneVolume

Figure 22. Mean Shell Size (Length(Length Times Width) vs. NeatMeat Volume (Shucked(Shucked CountCount PerPer Pint)Pint) ofof ThreeThree GroupsGroups of Kumamoto Oysters Tray Culture at Different Depths.Depths. Poor shell growth in thethe station-station­

ary intertidal tray was largelylargely duedue toto thethe highhigh tidaltidal levellevel ofof thethe tray.tray.

In suspended trays growth waswas equalequal at all depths after 19 months, butbut

growth appears muchmuch betterbetter nearnear the surface on suspended strings (13

months after planting) being usedused inin anotheranother study.study. In yearsyears of very

low winterwinter salinities, growth appearsappears toto be slightlyslightly betterbetter inin deepdeep

water levels where salinitiessalinities areare highest;highest; inin yearsyears ofof lessless severesevere salinities,salinities,

growth is better near thethe water's surfacesurface wherewhere foodfood productionproduction isis greatest.greatest.

String vs. Tray Culture.Cuiture. Oysters on rack stringsstrings areare thethe smallest,smallest,

probably due to their tidal exposure.

Heavy fouling byby mussels on the boom log strings probably retarded

oyster growth.growth. Many oysteroyster clustersclusters werewere completelycomp letely coveredcovered withwith mussels.musse Is.

Growth was also impaired by thethe largelarge numbernumber ofof spatspat perper cultchcultch. shell.shell.

Crowded conditions resulted in selfculling,selfculling, the loose oysters beingbeing 14. held inin placeplace byby bysalbysal threadsthreads ofof niissels. llIlSsels. We recommend that cultch that hashas no more than 20 spatspat perper sheshell11 bebe used for stringstring culture

(preferably(preferably 10-15).10-15). Thinning could be done but this would require con-con­ siderable time, labor, and a placeplace toto putput the culled oystersoysters untiluntil theythey reach a marketable size. We also recommend that spat on strings be planted after the peak of the spring set of DRJSselmussel larvae (about(about April 1 in Yaquina Bay).Bay).

Winter Spat Survival.Survival. The mean survival ofof 45%45% isis excellent;excellent; however,hCMever, some of the spat werewere muchmuch larger whenwhen plantedplanted than is imported seed at planting. Because of the somewhat mysterious mortalitymortality of the September­September- planted spat,spat, more information should be obtained in the future during this time period. Oyster larvaelarvae in the OSU hatcheryhatcheiy have also experienced high mortalities duringduring September.September. Vitality of spat set in September may also bebe low sincesince this broodbrood reflected the lowest survivalsurvival of the four broods used in thisthis study.study.

ABALONE STUDIES

Methods

Adult red abalone (llalioio(Haliotis r'Ufescens)rufeacene) were obtained from the coastal waters of southernsouthem Oregon near BrookingsBrookings andand fromfrom Whale CoveCove aa short dis-dis­ tance north ofof Newport.Newport. These adults were usedused forfor spawningspawning stock.stock.

The adultsadults were stimulated toto spawnspawn byby temperaturetemperature fluctuation.fluctuation.

The water temperature waswas increased from 15 C to 19-20 C in a period of

6 hours. After it reached 19-20 C, it was allowedallowed to cool. This procedure had toto be repeated several times before the abaloneabalone would spawn. After spawning, the fertilized eggs werewere siphoned out of the spawning tray through a filter andand placed inin anan incubationincubation tray.tray. After 24 hours the IS.15.

trochophore stage was reached andand thethe abaloneabalone trochophorestrochophores beganbegan swimming.swimming.

The trochophores were siphoned out of the incubation trays and placedplaced in

clean trays with freshfresh seasea water.water.

Results

The spawned eggs of the abalone obtained from southern O):egonOregon were

successfully fertilized andand thethe resultantresultant trochophorestrochophores survivedsurvived aa week.week.

The abalone trochophores became entangled in mucus stringsstrings, l clumped

together, andand couldcould notnot set.set. A second group of adultadult abalone were obtained

from Whale Cove. Only the males couldcould be inducedinduced toto spawn.spawn. More adults

were collectedcollected fromfrom southern Oregon but they dieddied while being transported

to the Newport Laboratory.Laboratory.

DiscusDiscussion si on

Adult red abalone werewere successfully spawned in the laboratorylaboratory but

problems arose when the trochophore larvaelarvae became entangled in mucus.

Before further spawnings are attempted a more extensive literatureliterature survey

will be made concerning spawning techniquestechniques.* Contact will be made with

biologists who have successfUllysuccessfully spawned and reared juvenile abalone.

More consideration will be given to the conditions of shipment of adult

red abalone to prevent mortalities such as have previously occurred.

PROGRESSiJtteIeI1 :41 TOWARD OBJECtIVES

The objectives ofof thethe Clam-Oyster-AbalofleClam-Oyster-AbaloI,e rearing'rearing project atat itsits inception was to develop methods ofof spawning and rearing all native species of clams, native oyster andand thethe exoticexotic PacificPacific oyster.oyster. The longlong range goal of the project was to develop methods of massmass culturing these animals to supplement naturalnatural reproduction and create newnew clam bedsbeds wherewhere adverse waterwater currents prevent setting. 16.16 Oyster cultureculture progressed toto thethe point thatthat wewe phasedphased outout thisthis portion ofof thethe program. program. Working cooperatively cooperatively withwith Oregon State State University, techniques werewere developeddeveloped for for spawningspawning and and rearing rearing oysters oysters inin mass culture.culture. We conducted conducted the the last last of of ourour field testingtesting in in FY FY 1971. 1911. Oregon StateState hashas built aa pilotpilot oyster oyster hatchery hatchery toto demonstrate demonstrate thethe practicality ofof oysteroyster hatcheries to thethe industry.industry. Our studiesstudies on fieldfield culture culture methods methods andand spat survivalsurvival showshow thatthat hatcheryhatchery seedseed isis asas good good asas importedimported seed and off­off- bottom cultureculture willwill increase survivalsurvival andand growthgrowth raterate of oysters.oysters. We have have spawned spawned and and reared reared all all of of thethe nativenative clamsclams toto some some degreedegree The most successful have beenbeen the the butter, butter, gaper,gaper, andand thethe nativenative andand Manila littlenecks. littlenecks. Razor clams andand cocklescackles need considerableconsiderable workwork before we cancan considerconsider our techniques to bebe ofof value value and and more more refinementrefinement isis neededneeded in techniquestechniques for butterbutter and and gapergaper clams.clams. While effort effort toto broadenbroaden the time period overover whichwhich gapergaper clamclam larvaelarvae can bebe obtained continued inin FYPY 1911, 1971, most most study study was was put put on on learning learning how how to to successfully successfully transplanttransplant the young gaper, gaper, butter, butter, andand Ii littleneckttleneck clamsclams to to thethe fiefield.ld. Progress has been encouraging with with native native andand mani manila la Ii littlenecks.ttlenecks . We now now fee feel1 thatthat we cancan mass mass rear rear the the littlenecklittleneck species andand can contribute toto our inverte-inverte­ brate resource.resource. This willwill be field testedtested duringduring fiscalfiscal 1972. 1912. Techniques forfor spawning andand rearingrearing abalone areare beingbeing developed.developed.

LITERATURE CITED Phibbs, F.F. D.D. 1968. Laboratory hatching hatching andand rearing rearing ofof PacificPacific coastcoast clams andand oysters.oysters. Commercial FisheriesFisheries ResearchResearch andand Development Development Act. Progress Report,Report, JulyJuly 1, 1967,1961, toto JuneJune 30,30, 1968.1968. Fish Comm. Comm. of Oregon.Oregon. 12 p. 1969. Laboratory hatching hatching and and rearing rearing ofof PacificPacific coastcoast clams andand oysters.oysters. Commercial Fisheries Fisheries ResearchResearch andand Development Development Act. Progress Report, July 1,1, 1968,1968, toto June June 30,30, 1969. 1969. Fish Comm. Comm. of Oregon.Oregon. 15 p. ______1910.1970. Laboratory hatching hatching and and rearing rearing ofof PacificPacific coastcoast clams andand oysters.oysters. ComercialCommercial FisheriesFisheries ResearchResearch andand Development Development Act. Progress Report, JulyJuly 1,1, 1969,1969, toto June June 30,30, 1970.1910. Fish Comm. Comm. of Oregon.Oregon. 16 p.