Ottawa, 1969 PACIFIC OYSTER CULTURE in BRITISH COLUMBIA Spawning of Pacific Oysters in Pendrell Sound

it DFO - Library / MPO - Bibliothèque In 1 1111 I III 11111 12039410 PACIFIC OYSTER CULTURE in British ele Columbia by D. B. Quayle Fisheries Research Board of Canada, Ottawa, 1969 PACIFIC OYSTER CULTURE IN BRITISH COLUMBIA Spawning of Pacific oysters in Pendrell Sound. I , BULLETIN 169 Pacific oyster culture in British Columbia By D. B. Quayle Fisheries Research. Board of Canada Biological Station, Nanaimo, B.C. FISHERIES RESEARCH BOARD OF CANADA Ottawa 1969 S'1 il ' c 2- (3 Crown Copyrights reserved Available by mail from the Queen's Printer, Ottawa, and at the following Canadian Government bookshops: HALIFAX 1735 Barrington Street MONTREAL Aeterna-Vie Building, 1182 St. Catherine Street West OTTAWA Daly Building, Corner Mackenzie and Rideau TORONTO 221 Yonge Street VANCOUVER 657 Granville Street WINNIPEG Mall Center Building, 499 Portage Avenue or through your bookseller Price $5.00. Catalogue No. Fs 94-169 Price subject to change without notice The Queen's Printer Ottawa, Canada 1969 Bulletins of the Fisheries Research Board of Canada are designed to assess and interpret current knowledge in scientific fields pertinent to Canadian fisheries. Recent numbers in this series are listed at the back of this Bulletin. Editor: J. C. STEVENSON, PH.D. Associate Editor: L. W. BILLINGSLEY, PH.D. Assistant Editor: R. H. WIGMORE, M.SC. Production: R. L. MacIntyre Fisheries Research Board of Canada Office of the Editor 116 Lisgar Street Ottawa 4, Ontario, Canada The Board also publishes the Journal of the Fisheries Research Board of Canada in annual volumes of monthly issues, an Annual Report, and a biennial Review of investigations. Fisheries Research Board of Canada publications are for sale by the Queen's Printer, Ottawa. Remittances must be in advance, payable in Canadian funds to the order of the Receiver General of Canada. Publications may be consulted at Board establishments located at Ottawa; Nanaimo and Vancouver, B.C.; Winnipeg, Man.; Ste. Anne de Bellevue and Grande-Rivière, Que.; St. Andrews, N.B.; Halifax and Dartmouth. N.S.; Ellerslie, P.E.I.; and St. John's, Nfld. Contents ABSTRACT, Xi INTRODUCTION, 1 HISTORY, 1 TAXONOMY, 3 Native oyster, 4 Eastern oyster, 6 Pacific oyster, 6 Hybrids, 8 ANATOMY, 8 Shell, 8 Pearls, 11 Body, 11 Mantle, 13 Gills, 15 Adductor muscle, 18 Digestive system, 18 Circulatory system, 2 1 Nervous system, 22 Reproductive system, 23 REPRODUCTION, 23 Sexuality, 23 Gonad development, 25 Spawning, 28 Time of spawning, 29 Larval development, 30 Growth of the larvae, 31 Setting, 31 GROWTH, 34 Growth in general, 34 Growth of the spat, 37 Growth variability, 38 Seasonal shell growth, 40 OYSTER FEEDING, 43 Food, 43 Fatness cycle, 46 Factors influencing feeding, 48 BREEDING, 48 Breeding history, 48 Stimulated spawning, 48 Temperature, 50 Larval movements, 52 Larval mortality, 54 OYSTER CULTCH, 57 Shell cultch, 57 Cemented circles, 59 Contents -- Continued Methods of exposing cultch, 60 Ideal cultch, 64 SPATFALL FORECASTING, 65 Necessity for forecasts, 65 Technique, 65 PENDRELL SOUND SEED, 69 Description, 70 Temperature, 70 Salinity, 73 Currents, 76 Spatting, 77 Vertical distribution of spatfall, 77 JAPANESE SEED, 82 Packing, 83 Inspection, 84 Pests, 87 OYSTER CULTURE, 88 Flow diagram of cultural operations, 89 Handling seed, 89 Spreading, 90 Planting density, 90 Seed ground, 91 Separating clusters, 92 Oyster ground, 96 Water quality, 96 Type of bottom, 96 Tide level, 96 Bottom consistency, 97 Wave action, 97 Eelgrass, 98 Ice, 98 Efficient use of ground, 98 Improving ground, 99 HARVESTING, 100 Hand picking, 100 Tonging, 101 Drag dredging, 102 Hydrau'.ic dredging, 102 Transportation, 103 Gear, 104 PROCESSING, 104 Hand shucking, 104 Mechanical shucking, 106 Shell disposal, 106 Washing, 107 Packaging, 108 Viii Contents — Continued STORAGE, 109 Shell stock, 109 Wet storage, 109 Dry storage, 110 Storage of shucked oysters, 110 Sanitary regulations, 110 Refrigeration, Ill PRODUCTIVITY, 112 Mortality, 113 Natural mortality, 113 Competition for space, 113 Silting mortality, 114 Cluster separation, 115 Condition, 115 Meat yield, 120 OYSTER PRODUCTION, 122 Production factors, 127 Economics of oyster production, 128 RAFT CULTURE, 129 Rack culture, 133 Stick culture, 134 NUTRITIVE VALUE AND CHEMICAL COMPOSITION, 135 Food value, 137 MARKETING, 138 PROCESSED OYSTER PRODUCTS, 138 Canned smoked oysters, 138 Canned oysters, 139 Oyster stew, 139 Frozen oysters, 139 Half shell, 139 POLLUTION, 140 Industrial pollution, 140 Kraft pulp mill pollution, 142 Experimental design, 142 Results, 143 Growth, 144 Log booming, 144 Heavy metal pollution, 145 Sewage pollution, 146 Pollution in growing waters, 146 Purification of shellfish, 147 Shellfish purification procedures, 148 Chlorination system, 148 British ultraviolet system, 149 Purdy ultraviolet system, 150 Processing and pollution, 151 ix Contents - Continued PARALYTIC SHELLFISH POISON, 151 PREDATORS AND PESTS, 154 Protozoa, 154 Boring sponge, 154 Boring sea worm, 155 Burrowing shrimps, 156 Parasitic copepod, 157 Crabs, 157 Oyster drills, 159 Starfish, 161 Chemical control of predators and pests, 163 DISEASE, 164 Malpeque disease, 164 Shell disease, 165 Disease in Chesapeake Bay, 165 Summer mortalities, 165 Foot disease, 165 Denman disease, 166 ORGANISMS ASSOCIATED WITH OYSTERS, 168 Sponges, 168 Coelenterates, 168 Worms, 169 Crustacea, 169 Molluscs, 171 Echinoderms, 173 Tunicates, 173 Eelgrass, 173 Seaweed,174 LEASES AND LEASING, 1 74 Leasing Crown land, 174 Method of acquiring leases, 175 Lease forms, 176 Cost of leases, 177 Protection of leases, 178 ADMINISTRATION, 178 History, 178 Government departments, 179 Oyster regulations, 180 RESEARCH, 182 THE FUTURE OF THE OYSTER INDUSTRY IN BRITISH COLUMBIA, 182 ACKNOWLEDGMENTS, 184 READING LIST, 184 GLOSSARY, 185 APPENDICES A-E, 189-192 I ABSTRACT Of the three species of oysters (Crassostrea gigas, Crassostrea virginica, Ostrea lurida) that occur in British Columbia, only the imported Japanese oyster (C. gigas) is cultured at the present time. The anatomy of C. gigas is described in some detail. Sexes are separate but may change over winter. Gonads develop in spring and are generally ripe by mid-May with spawning during July and August. The larval period lasts between 15 and 30 days depending on temperature. Growth of the Pacific oyster (C. gigas) is very variable but in the Strait of Georgia few oysters are marketed before 3 years of age. The condition of oysters is also variable but optimum fatness occurs during April. Successful breeding of the species in British Columbia is irregular except at Pendrell Sound. Spawning occurs frequently but the larvae fail to survive. Widespread breeding in all Strait of Georgia growing areas produced extensive "wild" populations in 1942 and 1958. The standard cultch used for collecting seed is the string of punched oyster shell. These are usually suspended from rafts, for cultch placed on the shore is much less efficacious. Various other cultch materials have been used including cement-dipped wood-veneer circles. Spatfall forecasts are made for Pendrell Sound where unique hydrographie and topographic features make the area a consistent seed producer. Japanese seed is also collected on shell cultch and is shippe.d in early spring as deck cargo in wooden cases. Japan, originally the sole source of seed, now exports very little to British Columbia. Oyster ground, whether used for planting seed, growing, or fattening, should be at the correct tide level. This is usually in the lower third of the tidal zone, with the firmest available bottom consistency and protected from exces- sive wave action. The seed is spread on ground which is firm in order to reduce silting mortality. The standard planting density is about 25-50 Japanese seed cases or its equivalent per acre and this represents between a quarter and half a million spat. After a year on the seed ground the clusters are separated either by hand or by dragging the bed with a spring-toothed harrow. The broken clusters may be transplanted to a growing area and even subsequently to fattening ground. The number of transplanting operations is variable depending on the type and amount of ground available. The oysters are harvested either by hand-picking at low tide or by drag or hydraulic dredge at high tide and taken to the shucking house. Shucking is done entirely by hand under strict sanitary regulations which also cover washing, packing, storing, and shipping. Productivity of an oyster bed is influenced by the oyster growth rate, condition, and mortality. The causes of mortality include predation, disease, competition for space on the shell, silting, and cluster separation. Oyster production in British Columbia began as early as 1884 with the native oyster (O. lurida). From a value of $100,000 in 1944, almost entirely from Pacific oysters, production rose in 1963 to a value of $635,000 for 170,375 gallons, equivalent to about 1,400,000 pounds of meat. Since then production has dropped slightly. The half-shell trade in Pacific oysters is extremely small and virtually all are marketed either for table use or as soup and stew. There is a small production of canned smoked oysters. xi Pollution is an increasingly serious problem. The sources of industrial pollution are pulp mills, log booming, and mining operations; bacteriological pollution emanates from improper sewage disposal in built-up areas. Paralytic shellfish poison may also occur in oysters. Predator and pest problems are relatively few. Among the serious predators are sea stars, drills, and crabs. Foreshore is held by the Crown in the right of the Province and is ]eased for oyster culture by the British Columbia Department of Lands. Administration of the oyster industry involves a number of departments of both the Federal and Provincial Governments. The future of the industry depends on how well the problems of pollution and industrial encroachment are solved. Production from the relatively small amount of intertidal ground will be unable to supply the expanding market as the population grows. It will be necessary to utilize marginal ground, subtidal areas, and raft culture techniques.

Load more