JERRY E. CLARK and R. DONALD LANGMO

Oyster Seed Hatcheries on theU.S. West Coast: An Overview

Introduction

Oyster production in the UnitedStates has been diminishing for nearly80 years. Natural disasters (includingdisease and predation), pollution, silta­tion, and land reclamation projectshave all contributed to the decline.Present U.S. production is not evenequal to what once came from theChesapeake Bay alone. 1 Meanwhile,oyster imports have been increasing(Table I).

Table 1.-UnKed States oyater supplies, 196G-77,ln mil­lions of pounds.

Oyster supplies

Year U.S.' Imports' Total West coast'

1960 60.0 6.6 66.6 11.01961 62.3 7.3 69.6 10.21962 56.0 7.4 63.4 10.81963 58.4 8.9 67.3 9.81964 60.5 8.2 68.7 10.01965 54.7 9.0 63.7 9.21966 51.2 12.0 63.2 7.81967 60.0 17.7 77.7 7.71968 61.9 15.6 77.5 7.81969 52.2 16.6 68.8 7.01970 53.6 15.5 69.1 8.01971 57.9 9.7 67.6 8.11972 52.5 22.3 74.8 7.31973 48.6 18.5 67.1 6.41974 44.9 16.0 60.9 511975 53.2 12.4 65.6 5.91976 54.4 18.0 72.4 N.A'1977 46.0 22.8 68.8 N.A.'

'For 1960-1973, U.S. Department of Commerce (1974); for1974-77, U.S. Department of Commerce (1976).'PUblished and unpublished data from Department of Fishand Game, California; Department of Fisheries, Washington;Department of Fish and Wildlife, Oregon.'Not available.

I At the tum of the century, nearly 80 millionpounds of oysters were harvested from theChesapeake Bay (Matthiessen, 1971). In 1975the total U .S.landings of oysters were reported as53.2 million pounds (U .S. Department of Com­merce, 1976).

10

Though U. S. oyster industry prob­lems have been substantial, interest inidentifying and solving the problemshas accelerated. One measure of thisresearch effort lies in a partial 22-year(1948-72) bibliography (Joyce, 1972)devoted almost entirely to oysters. Itcites 4,117 references that appear at anaccelerated rate.

A limited, but important, portion ofthe total research effort outlined byJoyce (1972), concerns hatchery prop­agation of "oyster seed," a looselydefined term referring to juvenile oys­ters of various ages which oyster grow­ers place in suitable habitat. Oysterseed production, which includes thespawning of adults and a relativelyshort free-swimming larval period, hasbeen an undependable link in thenatural reproductive cycle of oysters.

Formal research was begun over 100years ago to attempt to spawn oystersunder controlled conditions and to im­prove on the chances of survival of thelarvae and juvenile oysters (Brooks,1879). A result of this has been theestablishment of a small number ofcommercial oyster hatcheries. Thispaper discusses the role of commercialoyster hatcheries on the U.S. westcoast.

Oyster Seed

Oyster seed may be placed by thegrower into oyster beds in place of, orin addition to, those spawned and oc­curring naturally. Initially, oystergrowers did not need to seed their beds.During the summer, resident adult oys­ters would spawn and the eggs wouldhatch in the warm waters surroundingthe beds. Then, after a fairly short free-

swimming larval period, the oysterswould set on shells in the beds. Manygrowers facilitated the natural settingprocess by spreading cleaned shells ofpreviously harvested adults in the beds.

Reliance on natural spawning hasdeclined over the years due to somecombination of the physical destructionof suitable available growing areas,such as pollution of the oyster waters,which kills the delicate oyster larvae,and the practice of growing trans­planted oysters in water too cold to in­duce spawning but warm enough toraise oysters. The inhibiting effect ofcold water on spawning is especiallyprevalent on the U.S. west coast wherethe Pacific oyster, Crassostrea gigas, iscultured (Steele, 1964). The west coastindustry was built and, to a large de­gree, is still dependent upon growersbeing able to purchase Pacific oysterseed to restock growing beds.

Seed is purchased in either the"cultch" or "cultchless" form. Seedon cultch consists of cleaned adult oys­ter shell (cultch material) to which sev­eral young oysters (spat), have becomepermanently attached. Cultchless seedare single young oysters, availablefrom some hatcheries, which haveeither been removed from the surface ofinitial attachment, such as plasticsheets, or were originally set individu­ally on small pieces of shell or othercalcium carbonate material.

Prior to 1971 the west coast oysterindustry was heavily dependent onshipments of oyster seed on cultch fromJapan. Oyster seed is collected in Japanon oyster shell which is punched andstrung on wire. Each wire is about 6 feetlong and contains 100 or more pieces ofshell. Ten such wires, known individu­ally as ren, equal a case, containingbetween 13,000 and 20,000 spat.

Jerry E. Clark is a Research Assistant and R.Donald Langmo is an Associate Professor withthe Department of Agricultural and ResourceEconomics, Oregon State University, Corvallis,OR 97331. This work was carried out under aresearch grant sponsored by the Oregon StateUniversity Sea Grant College Program, sup­ported by NOAA, Office of Sea Grant, Depart­ment of Commerce, under contract #04-7-158­44085.

Marine Fisheries Review

The rens are used to collect spat bybeing suspended in waters rich in oysterlarvae during the spawning season.Then, carrying their load of set oysters,the wires are removed from the water,graded for spat count, packed inwooden crates, and shipped by boat tothe United States. During transit thecrates of cultch are periodically sprayedwith seawater.

Since about 1971, substantial andmore or less consistent additions to thesupply of oyster seed have becomeavailable. This seed is caught bymethods similar to the Japanese, but inwest coast waters. Before 1971, naturalspawning was quite irregular for thethree natural spawning areas on thewest coast: Dabob and Willapa Bays inWashington, and Pendrell Sound inBritish Columbia.

In 1971, after more than 20 years ofvery undependable west coast seedproduction, 33,000 cases of seed werecollected from a natural spawn inDabob Bay. In the previous year, forcomparison, the total volume of seedplanted in the entire State of Washing­ton was only 27,000 cases, of which22,000 were imported from Japan(Westley, 1976). Since 1971, therehave been 4 years when more than30,000 cases of seed have been col­lected in Dabob Bay: 1972, 1973,1974, and 1977. There was a completeset failure at Dabob Bay in 1975 and1976.

Hatchery Technique Developments

The current emphasis on hatcherytechniques to produce oyster seed ismotivated by the lack of a constant westcoast source of seed and a threefoldincrease in the cost of Japanese seedbetween 1960 and 1975. Developingcommercial hatchery methods to re­place total reliance on natural sets hasbeen at least a 100-year endeavor. Thefirst report of successful artificialspawning of oysters was in 1879(Brooks, 1879). Brooks was able to de­velop free-swimming oyster larvaefrom eggs and sperm stripped fromadult female and male oysters duringthe normal spawning season.

All the steps in the hatchery process

December 1979

were not completed by Brooks becausehe was unable to rear the larvae he hadhatched. Larval rearing remained thecentral hatchery problem for decadesdue to inadequate information on oysterdiets. Two years after Brooks' workand in spite of a deficiency in nutritionalinformation, M. Bouchen-Brandeley inFrance was able to spawn oysters, raisethe larvae in large outdoor ponds, andfinally set the larvae on collectors (Kel­logg, 1910). Apparently, natural nutri­ents in the large ponds were sufficientfor the larvae.

Following Brandeley, and during theearly part of the 20th century, mostresearch was directed toward improv­ing the techniques of spawning and lar­val rearing. Experimentation with set­ting materials and techniques, is morerecent.

Some of the most important researchinto the spawning characteristics ofoysters was done by Victor L. Loosa­noff (1937). Loosanoff's work wasbuilt, at least in part, on clam researchdone earlier by David Belding (1910)and Irving Field (1924). Belding andField are most responsible for identify­ing and experimenting with the vari­ables such as water temperature, salin­ity, and chemicals which affect time ofspawning and degree of success. Loos­anoff (1945) was the first to report suc­cessful experiments to induce spawningof oysters out of season. Loosanoffdoes acknowledge, however, thatothers, most notably D. L. McKernanand Vance Tarter, were simultaneouslyachieving the same results at the Stateof Washington oyster laboratory at GigHarbor.

Some of the most important researchleading to successful commercial de­velopment of oyster hatcheries relatesto larval rearing. Not until 60 yearsafter Brooks' work was definitive re­search done on the diet of oyster larvae.In England, Bruce et aI. (1940) pub­lished the first results on oyster larvaegrowth rates associated with variousalgal diets. Their work was based onearlier studies in England during the1930's by H. A. Cole (1937) on theEuropean oyster, Ostrea edulis. It wasnot until 1953 that a similar study onlarval diets was completed by Davis

(1953) in the United States for the Vir­ginia oyster, Crassostrea virginica. Asstated, most research into the tech­niques and materials needed to set oys­ter larvae occurred rather recently.

Most accounts attribute the first de­velopment of "cultchless" oyster set­ting techniques to W. W. Budge in1967, who was working for PacificMariculture2 (Dupuy et aI., 1977), acommercial oyster hatchery in Califor­nia. However, one important develop­ment in setting techniques, occurringnearly a half century earlier is oftenoverlooked. Most of those who havestudied the history ofoyster seed hatch­eries attribute to W. F. Wells, workingin 1920, the first successful spawning,rearing, and setting of oysters inconfined jars and tanks in a laboratory.These three steps are essential to acomplete hatchery. Previous successfullarval rearing took place only in largeoutside ponds.

One important aspect of Wells' workappears to be overlooked. Wells (1920)set oysters on boards covered with alime and sand mixture. As the set juve­nile oysters grew, they crowded eachother and began to turn up on edge andbreak loose from their attachments.Following separation from the boardsthe spat were raised in trays in seawa­ter. The young spat were subsequentlyplaced in growing beds upon attainingsufficient size, as single unattachedoysters. Apparently Wells developedone of the earliest "cultchless" hatch­ery techniques, as well as providing theearliest example of the total hatcheryconcept.

Research effort and success over thepast century are reflected in the prac­tices of current commercial oyster seedhatcheries. The major steps for the sev­eral variations in hatchery practices aresummarized in Figure 1. These stepsapplied in unison with knowledge aboutwater quality and disease control havesubsequently reduced the risks inpropagating juvenile oysters or larvae.

2Reference to trade names or commercial firmsdoes not imply endorsement by the NationalMarine Fisheries Service, NOAA.

11

OYSTER LARVAE

CULTCHLESS SEED

30liphant, M. S., Associate Marine Biologist,Department of Fish and Game, California StateFisheries Laboratory, Long Beach, Calif., pers.commun., 1977.4The seed planted in Oregon and California areestimates computed by dividing annual oysterproduction in each of those states by a conversionfactor of 20 gallons of production per case of seedplanted. The conversion factor is approximatelythe average return in the State of Washingtonbetween 1966 and 1975. If, for example,1,000.000 pounds are harvested, and a gallon ofoysters weighs approximately 8 pounds, then itcan be estimated that 6,250 cases of seed wereplanted [(1,000,000 pounds)/(8 pounds/gallon)/(20 gallons/case)1to achieve that production.

5,832,417 pounds, was produced withsuch techniques (Case 1976, Moos,1975, and Oliphant3).

Since bottom culture, the predomi­nant method, employs oyster seed oncultch, there is a sizable demand forsuch seed. A rough estimate of thequantity of seed on cultch demanded,based on west coast use during the past10 years, runs about 50,000 cases peryear. It is common for the total to bevery much higher or lower during indi­vidual years. The estimate is an aver­age, based primarily on statistics oftotal production and cases of seedplanted, provided by the WashingtonState Department of Fisheries. 4

The immediate future holds littlepromise that the total seed planted oncultch will significantly exceed 50,000cases. In fact, since the 1950's, the totalseed planted in the State of Washingtonhas declined from an average of 53 ,000cases to 39,000 cases per year duringthe first 6 years of the 1970's. How­ever, since an increase in the amount ofseed planted might be beneficial to oys­ter hatcheries, there is some merit inexploring ways such an increase couldcome about.

Several ways to increase total oysterproduction are based on techniques ofproduction different from the tradi­tional bottom culture. Many of the al­ternative culture methods do employseed on cultch, however. A goodsynopsis of alternatives to bottom cul­ture is presented by Bardach et al.(1972). In general, the use of stakes orsuspending rens from rafts allowsgrowers to generate greater production

seed. The following analysis of the dif­ferent cultural techniques which em­ploy both seed on cultch and cultchlessseed indicates the forces affecting thedemand for oyster seed.

Seed on Cultch

The choice of cultural technique forwest coast oyster growers is and hasbeen relatively easy. Here, bottom cul­ture is traditional, beginning with seedon cultch spread evenly on or near inter­tidal lands from barges during hightide. During low tide, the previouslyspread seed is more evenly distributedby hand. Hand-transfer of seed, thoughdeclining, is used to thin overly-densegrowing beds and to transfer oystersfrom seeding beds to fattening beds.

It takes from 2.5 to 4 years afterplanting before oysters are harvestedwhen raised on the bottom. Most, how­ever, are harvested after 3 years. Threeharvesting methods are currently in useon the west coast. The first involvesfilling large baskets by hand during lowtide and then at high tide locating thebaskets by an attached marking buoyand loading the then submerged basketsby crane onto the oyster barge. Thesecond method uses two drag linedredges mounted on each side of theoyster barge. Finally, and only recentlyintroduced to the west coast industry,rather large hydraulic suction dredgesare used to harvest and to transfer seedfrom bed to bed. Nearly the entire westcoast production of oysters in 1975,

'--__---'.J -I seillorvoe 1

SEED on CULTCH

1algae rearing 1-----------------.Iadults conditioning I-I adult spawning I-I larvae rearing 1­

'--------,------'1c"ltch handling I-----------------l

Oyster Hatcheries: Problemsand Potentials

Figure I.-Primary oyster hatchery operations for hatcheries producing larvae,cultchless seed, and seed on cultch.

The future of west coast oyster seedhatcheries depends on the interactionsof several variables which, together,determine the market for oyster seed.The market for seed involves such ele­ments as changing consumer demandfor oyster products to water tempera­tures in the natural seed-propagatingareas of Dabob Bay. This discussionidentifies and considers the effects ofchanges in the major variables. Theprobable immediate future of westcoast oyster hatcheries is briefly dis­cussed.

The method used to identify marketcomplexities faced by oyster hatcheriesis based on the decision-making pro­cess of the oyster growing rather thanthe hatchery operator. The oystergrower makes two decisions which af­fect the oyster seed market: 1) Whichmode of culture to use, and 2) where toget the desired type and quantity ofseed. The process followed here cap­tures only the major issues in the grow­er's decision-making process. As inother businesses, each member of theindustry faces different circumstances,which makes each decision-makingprocess unique.

Since the different oyster culturetechniques involve the use of differentforms and sizes of seed, the total size ofany particular segment of the industrydetermines the demand for each form of

12 Marine Fisheries Review

by using the water column instead ofthe bottom alone.

So far, very little west coast oysterproduction is done with alternativetechniques employing oyster seed oncultch. Two factors are mainly respon­sible for restricting movement into thealternative cultural techniques. Theprimary limiting factor is the belief ofmany growers that the cost of produc­ing oysters by methods using stakes,racks, or rafts is greater than the in­crease in returns from increased pro­duction. The word "belief" is usedbecause there are a few growers on thewest coast successfully employing cul­tural techniques other than bottom cul­ture.

The second limiting factor is bothsocial and political. Intensive culturalmethods involve placing structuressuch as stakes and racks on intertidalflats, or rafts or longlines in deep water.Stakes and racks employed in the inter­tidal areas are exposed during low tide,and can literally cover the bottom overlarge areas where oysters are cultivatedin this fonn. The stakes and racks, inthe eyes of many, are a fonn of visualpollution and may be vigorously op­posed. Rafts and longlines used indeeper water, also have negative visualaspects and, depending on location,may be impediments to navigation. Inview of these restraints, the movementinto intensive cultural techniques, evenif economically feasible, will developslowly, if at all.

Cultchless Seed

Use of cultchless seed on the westcoast is both limited and experimental.One Oregon grower rears cultchlessseed in stacks of trays until it is largeenough to be transferred to one of sev­eral layers in a wire cage where it re­mains with only periodic cleaning andthinning until harvest. This grower isonly one of a handful on the west coastwho has oyster ground which is notintertidal, and was successful in obtain­ing permits to place oyster-growingfacilities in navigable waters. Expan­sion of this method of production islimited primarily by the same restraintsas those experienced by nonbottom

December 1979

growers employing seed on cultch, dis­cussed previously.

Cultchless seed is also being experi­mentally placed in intertidal oysterground instead of the traditional seed oncultch. At present the practice looksuneconomic due to high mortality and,hence, low yield if small, less expen­sive seed is used, and too costly whenlarger, more expensive seed is used.The practice is not being ruled out,however, as only preliminary resultsare available.

5

Finally, the relatively small size ofcultchless seed (2-mm seed is sold)opens markets for cultchless seedwhich do not exist for the extremelybulky cultch type seed. Where 1millionspat would equal about 67 cases (167bushels) of seed on cultch, the sameamount of cultchless seed is equal toonly about I liter (slightly more than 1quart). Many millions of cultchlessseed oysters can, and are, being sentthroughout the world by hatcheries onthe west coast. The market for cultch­less oyster seed, while very small on thewest coast, may prove significantworldwide. Also, if some of the exper­iments mentioned earlier are success­ful, a modest expansion of the presentmarket for cultchless seed on the westcoast could occur.

Two conclusions regarding the de­mand for oyster seed are apparent fromthe previous discussion. A significantdemand exists for oyster seed and asignificant increase in that demand ispossible but not imminent. The likeli­hood of large increases in seed plantedon the west coast each year is not great.As mentioned, significant change inlocal seed demanded is possible, butonly if new production technologies,such as those which make use of theentire water column, are adopted.

There appear to be some goodreasons why this development will beslow. First, most of the alternativetechnologies will be practical only ifproduction costs can be reduced, a pro­cess that usually occurs rather slowly.

5Breese, w. P., Associate Professor of Fisheries,Oregon State University, Corvallis, Oreg., pers.commun., 1977.

However, the primary reason for ex­pecting only modest growth is related tothe sociopolitical issues. The use of thenation's estuaries is increasingly scru­tinized. As various user groups com­pete, the process of altering the presentuses becomes increasingly difficult.

Competing Seed Sources

The second major decision for agrower is where to buy seed. The ques­tion of a seed source (or sources) hasbecome complicated, especially since1971. At present, the west coast growercan choose among three potential seedsources: 1) Imported Japanese seed, 2)domestic and Canadian wild seed, and3) hatchery seed.

Ideally, the grower would like to ac­quire seed solely on the basis of thegreatest return per dollar spent. If thegrower were able to make a decision,based simply on the cost per case ofseed from each of the three sources, thetask would be relatively simple. Such acalculation, however, is not easily ac­complished. The fact that two cases ofseed have the same spat count does notmean they will produce a similaramount of oysters, even when grownunder the same conditions. Several fac­tors contribute to variations in produc­tivity.

One such consideration, for exam­ple, is the relative thickness of the un­derlying cultch material. Both wildseed and hatchery seed on the westcoast are caught on local oyster shell,which are relatively thick and not easilybroken. In contrast, Japanese seed iscaught on a thinner shell, which canincrease the amount of final productionper case. The Japanese seed can be bro­ken by hand, and sometimes even bycrowding of the growing oysters on it.In either case, the breakable thin shellseems to lead to decreased mortalityand, in turn, increased productivity.

Such differences in seed quality, re­gardless of the cause, complicates thegrower's objective of maximum returnper dollar spent on seed. Even if a deci­sion can be made about which seed ispreferred on the basis of quality, thereis a further problem: availability of seedfrom each of the three sources may varysignificantly.

/3

t

In 1971 nearly 30,000 cases of seedwere collected in Dabob Bay, Wash.The following year, orders for Japaneseseed in the State of Washingtondropped from 25,486 cases to 7,321cases. The same pattern existed for thenext 5 years. In 1976, after 2 years withno wild seed, growers in Washingtonordered large quantities of seed fromJapan. Then in 1977 large quantities ofwild seed were again collected inDabob Bay. A near failure in Japan tocollect seed in 1977, coupled with thelarge set in Dabob Bay, meant that in1978 little or no seed was imported.Wide variation in the supply of wildseed has provided a difficult marketingenvironment for the planning and de­velopment of west coast hatcheries.

The first oyster seed hatchery wasbuilt on the west coast in 1967 with thehopes of being able to compete withJapanese seed which was rapidly in­creasing in price (between 1960 and1975 the price tripled). Some seed wassold, but the hatchery eventually faileddue to biological problems. (Since thenthe hatchery has reopened, success­fully.)

During the 1970's other hatcherieswere opened, but the total seed sold orproduced by all hatcheries and used bygrowers on the west coast has neverbeen very large. Early in the 1970's theconsistent natural sets in Dabob Baymeant that hatchery seed had to com­pete with the relatively inexpensivewild seed as well as the more expensiveJapanese seed. The hatcheries werebasically unable to compete.

Finally, in 1975 and 1976 when therewas, for practical purposes, no wildseed collected on the west coast, thegrowers, especially in Washington,turned to the hatcheries and requestedthey produce the tens of thousands ofcases of seed the growers needed. Theoutcome was not unpredictable. After 4years of being unable to sell seed due tothe large natural sets, the remaininghatcheries simply were not in a positionto produce so much in such a short time.Thus, orders were sent to Japan in 1976for seed to be delivered in 1977.

Hatcheries have continued to exist onthe west coast despite the problems(five are in commercial operation), but

14

only one small hatchery of the five isstrictly independent of other incomesources, and sells seed to west coastoyster growers. Two hatcheries primar­ily produce cultchless seed, and dependin large part on sales of seed in Europe.The other two commercial hatcheriesare associated with organizations whichalso grow oysters.

1m et al. (1976) provided some in­sights into west coast oyster seed hatch­ery problems and their economic viabil­ity. The study indicated that hatcheriesappear to be economically feasible, butthere is some question about "whethermore than one or two plants could sur­vive .... " The original promise ofhatcheries - to guarantee seed of a con­sistent quality when, where, and in theform needed-although potentiallyfeasible, has not been sufficient toguarantee the survival of a large num­ber of hatcheries.

Hidu (1969) pointed out three obsta­cles to the successful development ofhatcheries: 1) The cost of alternativeseed sources; 2) the lack of develop­ment in demand for cultchless seed; and3) the failure to develop geneticallysuperior strains of oysters. The situa­tion has not changed appreciably.

Success in any of the three areaswould encourage the development of ahatchery industry. If costs of hatcheryseed can be reduced to compete withnatural sets, then growers will be morelikely to tum to hatcheries. If growersadopt techniques employing cultchlessseed, hatcheries already exist to supplythat seed. Finally, if geneticallysuperior strains of fast-growing or dis­ease-resistant oysters can be de­veloped, only hatcheries could producecommercial quantities of the new purestrains.

Although the past success for oysterseed hatcheries has been limited, thefuture holds several encouraging pros­pects with respect to the obstacles out­lined by Hidu (1969). One new idea toreduce the cost of hatchery seed is beingtested commercially in Oregon withthe sale to growers of setting size larvaeby a local hatchery. Setting the larvaeon cultch or as cultchless seed will be anactivity of the grower, not of the hatch­ery as in the past.

At this time, very little is knownabout the overall economics of such anoperation. One advantage of a hatcherywhich sells larvae is that many growersshuck their own oysters and, therefore,have cultch available, thus avoiding thecosts of hauling shell to and fromhatcheries or natural setting areas.

The traditional independent hatcheryproducing seed on cultch must acquireshell from growers, set the larvae, andthen transport the shell with attachedspat back to growers. Handling costsare likewise incurred by growers whotake shell to Dabob Bay to catch wildseed. A significant portion of the cost ofboth is the transportation of the bulkycultch. The farther the grower and thehatchery are from each other and fromDabob Bay, the more likely it is that thelarvae technique will be advantageous.It is no surprise, then, that the first oys­ter larva hatchery on the west coast wasbuilt in Oregon, which is a distancefrom the wild seed source in DabobBay, but close to producing areas whereoyster shell is abundant. Time will tellif the savings in transportation costs ofshell, and the existence of an assuredseed source, will be sufficient to makethe oyster larva technique competitivewith wild seed collection in DabobBay.6

The second concern expressed byHidu (1969), the full development ofcultural techniques employing cultch­less seed, is also receiving considerableattention on the west coast. The exis­tence of an expanding market for half­shell and baking oysters holds consid­erable potential. In both cases theproduct sold is a single adult oyster inthe shell, and the price is greater thanthat which the grower receives forequivalent amounts of shucked singleoysters broken from clumps of oystersraised on cultch. Since it is usually true

6 Analysis in this research is based on an assump­tion that large quantities of wild seed will beavailable from Dabob Bay on a regular basis.Three or four years of seed failure in Dabob Bay(not likely, but possible), and a continuation ofthe increase in the price of Japanese seed (verylikely), would lead to an immediate and sig­nificant improvement in both the acceptability ofhatchery seed to growers and economic stabilityof hatcheries.

Marine Fisheries Review

that well-formed oysters of a consistentsize and shape draw a better price in thehalf-shell market, the development oftechniques employing cultchless seed isindicated.

As discussed, the potential for pro­duction of cultchless oysters in trays orcages is probably limited by sociopolit­ical considerations. Hence, there willbe further impetus for developing alter­native techniques for growing cultch­less oysters.

At least two are presently beingexplored. The best known technique isthe placement of large singles on inter­tidal lands. The second includes severalideas, collectively known as "out­bay" culture. Out-bay culture is a pro­cess of growing oysters in trays andcages in large tanks, raceways, ortroughs. The holding areas are con­structed near a source of seawater, andpond-raised algae is used as a foodsource for the growing oysters.

Out-bay culture offers the advantageof increasing control of the environ­ment to the point where storms, silt,predators, and currents are not the prob­lems they are when oysters are raisedintertidally. Also, although out-bayculture operations will not be free ofsociopolitical constraints, they shouldbe relatively more free than operationswhich need to construct permanent orsemipermanent structures in bays andestuaries. However, a real impedimentdoes exist to the rapid development ofout-bay operations. Construction andpumping costs can be very high. Atpresent the technique is experimentaland no definitive answer is available onthe economic feasibility of out-bay cul­ture methods.

As in so many other areas of theoyster industry, further research isneeded in the area of out-bay culture.The real issue, however, is not whetherthe half-shell or baking oysters are pro­duced intertidally, out-bay, or anotherway, but the fact that cultchless seedwill be needed and hatcheries likelywill be the seed source. Therefore, asthe market for adult single oysters in­creases naturally or is induced throughmarketing promotions, the future ofoyster seed hatcheries is enhanced.

Finally, the third area referred to by

December 1979

Hidu (1969), genetics, while now ofrelatively minor importance, could pro­foundly affect the oyster industry. Forinstance, few Pacific oysters are sold inthe summer months on the west coastdue to the fact that the marketability ofoysters declines as the water tempera­ture increases and they approach theonset of spawning.

Another Asian species, Crassostrearivularis, might provide a partial solu­tion. There is speculation, though noconclusive documentation, that it maymake an ideal "summer oyster," sinceit apparently remains firm in west coastwaters throughout the summer. A firmoyster available during the summer ispotentially very important to the westcoast oyster industry. The many coastalsummer tourists of Washington, Ore­gon, and California could provide alarge market for such oysters.

A third Asian oyster, and a subspe­cies of Crassostrea gigas, theKumomoto, may also be produced byhatcheries. The Kumomoto is prizedfor its small size and as such, com­mands a price in the market from four tofive times that of the Pacific oyster.

The Kumomoto, like C. rivularis,also has desirable qualities through thesummer. Kumomoto seed used to beimported from Japan, but is no longeravailable. In the future, hatcheries willbe the only source for seed.

An additional issue related to genet­ics, which can have a positive influenceon hatcheries, is the potential develop­mentofan "improved" oyster. That is,at some point in the future there isreason to believe a more rapid growing,or a disease-resistant oyster, will be de­veloped. Again, only hatcheries couldprovide pure strains of such an oyster incommercial quantities. Genetic issuesmay, in the long run, be of the mostimportance to the future of hatcheries.When pure strains of oysters areneeded, whether they be C. rivularis,Kumomoto, or some as-yet unde­veloped "improved" oyster, hatch­eries likely will be the only source ofsupply.

Summary

Oyster hatcheries have been in exis­tence on the west coast since 1967 and,

despite early promise, have experi­enced only limited success. Problemsinclude the existence of unpredictablenatural sets of oysters in the State ofWashington, and the lack of develop­ment in cultural techniques employingcultchless seed.

There is, however, reason for op­timism. The hatcheries' ability to com­pete with natural sets is judged to beimproving, and there is evidence of agrowing demand for types of oysterseed which can not be met with naturalseed. More growers are likely to beeither switching to or starting up with atleast some of their production beingcultchless seed.

There is also reason to believe thathatcheries will continue to reduce costs;some by further advancement of tech­niques and equipment, and some bysuch radical moves as the sale of larvarather than seed to growers. Finally,and with a somewhat longer view inmind, both the development of geneti­cally superior oyster strains and theadoption of out-bay culture techniquesmight, some day, make the oyster in­dustry totally dependent on hatchery­produced oyster seed.

West coast oyster hatchery problemsneed not be viewed negatively. Thewest coast oyster industry is in a periodof transition. What was once an indus­try of numerous small, family-type op­erations is now, with respect to produc­tion at least, heavily dominated by largefamily and corporate enterprises. Theindustry is modernizing and experi­menting. Hatchery oyster seed produc­tion is just 11 years old on the westcoast. As with many innovative move­ments, there are some failures and somesuccesses. As this period of transitionmoves toward a close, it is believedhatcheries will find a more secure placein the oyster industry.

Literature CitedBardach, J. E., J. H. Ryther, and W. O. McLar­

ney. 1972. Aquaculture. The fanning and hus­bandry of freshwater and marine organisms.Wiley-Interscience, N.Y., 868 p.

Belding, D. L. 1910. Report upon the scallopfisheries of Massachusetts. Commonwealth ofMassachusetts, State Printers, Boston, p. I-51.

Brooks, W. K. 1879. Abstract of observationsupon artificial fertilization of oyster eggs: An

15

embryology of American oyster. Am. J. Sci.17:425-527.

Bruce,J. R., M. Knight, andM. W.Parke.I940.The rearing of oyster larvae on an algal diet. J.Maricult., Mar. BioI. Assoc. U.K. 24:337­374.

Case, E. 1976. Commercial food fish landings inpounds round weight by State of Oregon ad­ministrative district for calendar year 1975.Oreg. Dep. Fish Wildl., Salem, I p.

Cole,H. A. 1937. Experiments in the breeding ofoysters (Ostrea edulis) in tanks, with specialreference to the food of the larva and spat. Fish.Invest., Minist. Agric., Fish. Food (G.B.),Ser. II, 15(4),25 p.

Davis, H. C. 1953. On food and feeding of larvaeof the American oyster, C. virginica. BioI.Bull. (Woods Hole) 104:334-350.

Dupuy, J. L., N. T. Windsor, and C. E. Sutton.1977. Manual for design and operation of anoyster seed hatchery. Va. Inst. Mar. Sci.,Spec. Rep. 142, 104 p.

Field, I. A. 1924. Biology and economic value ofthe sea mussel Mytilus edulis. Bull. U.S. Bur.Fish. 38:127-259.

Hidu, H. 1969. The feasibility of oyster hatch­eries in the Delaware-Chesapeake Bay region.In K. Sprice, Jr. and D. L. Maurer (editors),Proceedings of the conference on the artificialpropagation of commercially valuableshellfish: oysters, p. 111-129. Univ. Del.,

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Newark.1m, K. H., R. S. Johnston, and R. D. Langmo.

1976. The economics of hatchery productionof Pacific oyster seed: a research progress re­port. Proc. Natl. Shellfish. Assoc. 66:81-94.

Joyce, E. A., Jr. 1972. A partial bibliography ofoysters, with annotations. State of Florida,Dep. Nat. Resour., Spec. Sci. Rep. 34, 846p.

Kellogg, J. L. 1910. Shell-fish industries. H.Holt and Co., N.Y., 361 p.

Loosanoff, V. L. 1937. Observation on propaga­tion of oysters in the James and Corrotomanrivers and seaside of Virginia. Va. Comm.Fish., Newport News, 46 p.

____ . 1945. Precocious gonad develop­ment in oysters induced in midwinter by hightemperature. Science (Wash., D.C.) 102:124-125.

Matthiessen, G. C. 1971. A review of oysterculture and the oyster industry in NorthAmerica. Woods Hole Oceanogr. Inst., WoodsHole, Mass., 52 p.

Moos, D. W. 1975. 1975 fisheries statistical re­port. Dep. Fish., Olympia, Wash., 115 p.

Steele, R. N. 1964. Immigrant oyster (Cras­sostreagigas) now known as the Pacific oyster.Warren Quick Print, Olympia, Wash., 179 p.

U .S. Department of Commerce. 1974. Basiceconomic indicators: oysters, 1947-1973. U.S.Dep. Commer. , NOAA, Natl. Mar. Fish.Serv., Curr. Fish. Stat. 6273, 57 p.

---_. 1976. Fisheries of the UnitedStates, 1975. U.S. Dep. Commer., NOAA,Natl. Mar. Fish. Serv., Curro Fish. Stat. 6900,100 p.

Wells, W. F. 1920. Growing oysters artificially.Conservationist 3: 151.

Westley, R. E. 1976. Oyster growing and culturein Washington State. Wash. Dep. Fish., PointWhitney Shellfish Lab., 12 p.

Selected ReferencesBaughmann, J. L. 1948. An annotated bibliog­

raphy of oysters, with pertinent material onmussels and other shellfish and an appendix onpollution. Texas A&M Research Foundation,College Station, 794 p.

Breese, W. P., andR. E. Malouf. 1975. Hatcherymanual for the Pacific oyster. Oreg. StateUniv. Sea GrantPubl. ORE54-4-75-002, 21 p.

____ , and W. Q. Wick. 1973. Oysterfarming. Oreg. State Univ. Sea Grant Rep. 13,8 p.

1m, K. H., and R. D. Langmo. 1977. Hatcheryproduced Pacific oyster seed. Oreg. StateUniv. Sea Grant Publ. ORESU-T-77-01O,80 p.

Loosanoff, V. L., and H. C. Davis. 1963. Rear­ing of bivalve molluscs. Adv. Mar. BioI. I: 1­136.

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