Scientific Excellence • Resource Protection & Conservation • Benefits for Canadians Excellence scientifique • Protection et conservation des ressources • Benefices aux Canadiens Intertidal Clam Surveys of British Columbia - 1991 • N. F. Bourne, G. D. Heritage, and G. Cawdell ~} ~~ "" I. Biological Sciences Branch ". ' ' . Department of Fisheries and Oceans Pacific Biological Station Nanaimo, British Columbia V9R 5K6 1994 Canadian Technical Report of Fisheries and Aquatic Sciences 1972 Fisheries Peches 1+1 and Oceans et Oceans Canada Canadian Technical Report of Fisheries and Aquatic Sciences Technical reports contain scientific and technical information that contributes to existing knowledge but which is not normally appropriate for primary literature. Technical reports are directed primarily toward a worldwide audience and have an international distribution. 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Les rapports epuises seront fournis contre retribution par des agents commerciaux. Canadian Technical Report of Fisheries and Aquatic Sciences 1972 1994 INTERTIDAL CLAM SURVEYS OF BRITISH COLUMBIA - 1991 by N. F. Bourne, G. D. Heritage and G. Cawdell1 Biological Sciences Branch Department of Fisheries and Oceans Pacific Biological Station Nanaimo, British Columbia V9R 5K6 1Present address: 205-254 Gorge Road East Victoria, B.C. Canada V9A 6W4 - ii - ~ Minister of Supply and Services Canada 1994 Cat. No. Fs 97-6/1972E ISSN 0706-6457 Correct citation for this publication: Bourne, N. F., G. D. Heritage, and G. Cawdell. 1994. Intertidal clam surveys of British Columbia - 1991. Can. Tech. Rep. Fish. Aquat. Sci. 1972: 155 p. - iii - TABLE OF CONTENTS Page LIST OF FIGURES . v LIST OF TABLES . viii ABSTRACT . ix PART I . 3 CAMPBELL RIVER AREA SURVEY . 3 Von Donop Inlet . 3 Physical Description of Beaches . 3 Clam Populations . 4 Marina Island . 5 Physical Description of the Beach . 5 Clam Populations . 5 Kanish Bay . 6 Physical Description of Beaches . 6 Clam Populations . 6 Cameleon Harbour . 7 DISCUSSION . 7 PART II ................................................ 8 BELLA BELLA TO QUEEN CHARLOTTE STRAIT SURVEY .......... 8 Seaforth-Spiller-Return Channel Area . 8 Physical Description of Beaches . 8 Clam Populations . 9 Other Observations . 1 0 Gale Passage . 1 0 Physical Description of Beaches . 1 0 Clam Populations . 11 Other Observations . 12 Thompson Bay . 13 Physical Description of Beaches . 13 Clam Populations . 13 Other Observations . 14 Stryker Island . 14 Physical Description of Beaches . 14 Clam Populations . 15 Other Observations . 16 Spider Anchorage . 16 - iv- Physical Description of Beaches . 17 Clam Populations . 1 7 Kwakshua Channel . 19 Physical Description of Beaches . 19 Clam Populations . 19 Rivers Inlet . 20 Physical Description of Beaches . 21 Clam Populations . 21 Other Observations . 22 West Gilford Island . 22 Physical Description of Beaches . 22 Clam Populations . 23 Indian Channel . 24 Physical Description of Beaches . 24 Clams Populations . 24 DISCUSSION . 25 BUTTER CLAMS . 25 LITTLENECK CLAMS . 26 MANILA CLAMS ...................................... 26 STUNTING . 28 COMMERCIAL POTENTIAL . 29 . OTHER SPECIES . 30 GENERAL SUMMARY . 30 ACKNOWLEDGEMENTS . 31 REFERENCES . 31 - v - LIST OF FIGURES Page Fig. 1. landings of intertidal clams, razor, butter, littleneck, manila and mixed, in commercial fisheries in British Columbia 1951-1991. 49 Fig. 2. Map of northern Strait of Georgia showing location of beaches sampled in May, 1991 ................................... 51 Fig. 3. Map of the British Columbia coast, from Bella Bella to Alert Bay, showing the location of beaches (circled numbers) surveyed in July 1991. 1. Seaforth-Spiller Return Channel, 2. Gale Passage, 3. Thompson Bay, 4. Stryker Island, 5. Spider Anchorage, 6. Kwakshua Channel, 7. Rivers Inlet, 8. West Gilford Island, 9. Indian Channel. 53 Fig. 4. Map of Von Donop Inlet showing location of three beaches surveyed, May 28, 1991. 55 Fig. 5. length frequency of butter clams from Von Donop Inlet and Kanish Bay, May 28-29, 1991. ................................ 57 Fig. 6. length and age frequencies of littleneck clams from Von Donop Inlet, May 28, 1991. ...................................... 59 Fig. 7. Growth rate of littleneck clams from Von Donop Inlet and Kanish Bay, May 28-29, 1991. ................................ 61 Fig. 8. length and age frequencies of manila clams from Von Donop Inlet, May 28, 1991. ...................................... 63 Fig. 9. Growth rate of manila clams from Von Donop Inlet and Kanish Bay, May 28-29, 1991 ...................................... 65 Fig. 10. Map of Marina Island showing sampling location, May 28, 1991 .... 67 Fig. 11. Length and age frequencies of littleneck clams from Marina Island, May 28, 1991. ...................................... 69 Fig. 12. Length and age frequencies of manila clams from Marina Island, May 28, 1991. ...................................... 71 Fig. 13. Map of Kanish Bay showing the location of three beaches surveyed, May 29, 1991. .. ....................................' 73 Fig. 14. Length and age frequencies of littleneck clams from Kanish Bay, May 29, 1991. ...................................... 75 Fig. 15. length and age frequencies of manila clams surveyed from Kanish Bay, May 29, 1991 ..................................... 77 Fig. 16. Map of the Cameleon Harbour showing the beach visited, May 29, 1991. 0 •••••••••••••••••••••••••••••••••••••••••••• 79 Fig. 17. Map of the Seaforth-Spiller-Return Channel area showing the location of beaches surveyed July 8, 1991 ..................... 81 Fig. 18. Length and age frequencies of littleneck clams from the Seaforth­ Spiller-Return Channel area, July 8, 1991. 83 Fig. 19. Length and age frequencies of manila clams from the Seaforth­ Spiller-Return Channel area, July 8, 1991. 85 - vi - Fig. 20. Growth rate of manila clams from the Seaforth-Spiller- Return Channel area, July 8, 1991. 87 Fig. 21. Map of Gale Passage showing the location of beaches surveyed July 9-10, 1991 ....................................... 89 Fig. 22. Length and age frequencies of butter clams from Gale Passage, July 9-10, 1991 ....................................... 91 Fig. 23. Length and age frequencies of littleneck clams from Gale Passage, July 9-10, 1991 ....................................... 94 Fig. 24. Length and age frequencies of manila clams from Gale Passage, July9-10,1991 ....................................... 95 Fig. 25. Growth rates of manila clams from North Gale Passage, and from the South Gale Passage-Thompson Bay area, July 9-1 0, 1991. 97 Fig. 26. Map of the Thompson Bay area showing the location of beaches surveyed, July 10, 1991. ..............................