Exploratory Intertidal Bivalve Surveys in British ...

Exploratory Intertidal Bivalve Surveys in British Columbia – 2004

G.E. Gillespie and N.F. Bourne

Fisheries and Oceans Canada Science Branch, Pacific Region Pacific Biological Station Nanaimo, British Columbia V9T 6N7

2005

Canadian Manuscript Report of Fisheries and Aquatic Sciences 2734

Fisheries and Oceans Canada

Pêches et Océans Canada

ii Canadian Manuscript Report of Fisheries and Aquatic Sciences Manuscript reports contain scientific and technical information that contributes to existing knowledge but which deals with national or regional problems. Distribution is restricted to institutions or individuals located in particular regions of Canada. However, no restriction is placed on subject matter, and the series reflects the broad interests and policies of the Department of Fisheries and Oceans, namely, fisheries and aquatic sciences. Manuscript reports may be cited as full publications. The correct citation appears above the abstract of each report. Each report is abstracted in Aquatic Sciences and Fisheries Abstracts and indexed in the Department’s annual index to scientific and technical publications. Numbers 1-900 in this series were issued as Manuscript Reports (Biological Series) of the Biological Board of Canada, and subsequent to 1937 when the name of the Board was changed by Act of Parliament, as Manuscript Reports (Biological Series) of the Fisheries Research Board of Canada. Numbers 1426 - 1550 were issued as Department of Fisheries and the Environment, Fisheries and Marine Service Manuscript Reports. The current series name was changed with report number 1551. Manuscript reports are produced regionally but are numbered nationally. Requests for individual reports will be filled by the issuing establishment listed on the front cover and title page. Out-of-stock reports will be supplied for a fee by commercial agents. Rapport manuscrit canadien des sciences halieutiques et aquatiques Les rapports manuscrits contiennent des renseignements scientifiques et techniques ques qui constituent une contribution aux connaissances actuelles, mais qui traitent de problèmes nationaux ou régionaux. La distribution en est limitée aux organismes et aux personnes de régions particulières du Canada. Il n’y a aucune restriction quant au sujet; de fait, la série reflète la vaste gamme des intérêts et des politiques du ministère des Pêches et des Océans, c’est-à-dire les sciences halieutiques et aquatiques. Les rapports manuscrits peuvent être cités comme des publications complètes. Le titre exact paraît au-dessus du résumé de chaque rapport. Les rapports manuscrits sont résumés dans la revue Résumés des sciences aquatiques et halieutiques, et ils sont classés dans l’index annual des publications scientifiques et techniques du Ministère. Les numéros 1 à 900 de cette série ont été publiés à titre de manuscrits (série biologique) de l’Office de biologie du Canada, et après le changement de la désignation de cet organisme par décret du Parlement, en 1937, ont été classés comme manuscrits (série biologique) de l’Office des recherches sur les pêcheries du Canada. Les numéros 901 à 1425 ont été publiés à titre de rapports manuscrits de l’Office des recherches sur les pêcheries du Canada. Les numéros 1426 à 1550 sont parus à titre de rapports manuscrits du Service des pêches et de la mer, ministère des Pêches et de l’Environnement. Le nom actuel de la série a été établi lors de la parution du numéro 1551. Les rapports manuscrits sont produits a l’échelon régional, mais numérotés à l’échelon national. Les demandes de rapports seront satisfaites par l’établissement auteur dont le nom figure sur la couverture et la page du titre. Les rapports épuisés seront fournis contre rétribution par des agents commerciaux.

Canadian Manuscript Report of Fisheries and Aquatic Sciences 2734

2005

EXPLORATORY INTERTIDAL BIVALVE SURVEYS IN BRITISH COLUMBIA - 2004

by

G.E. Gillespie and N.F. Bourne

Fisheries and Oceans Canada Science Branch, Pacific Region Pacific Biological Station Nanaimo, British Columbia V9T 6N7

ii

© Her Majesty the Queen in Right of Canada, 2005 Cat. No. Fs 97-4/2734E

ISSN 0706-6473

Correct citation for this publication:

Gillespie, G.E., and Bourne, N.F. 2005. Exploratory intertidal bivalve surveys in British Columbia – 2004. Can. Manuscr. Rep. Fish. Aquat. Sci. 2734: ix + 144 p.

iii

TABLE OF CONTENTS LIST OF TABLES.................................................................................................................................................... IV LIST OF FIGURES.................................................................................................................................................. IV LIST OF APPENDICES .........................................................................................................................................VII ABSTRACT ........................................................................................................................................................... VIII INTRODUCTION .......................................................................................................................................................1 METHODS...................................................................................................................................................................2 RESULTS.....................................................................................................................................................................3 SMITH SOUND ............................................................................................................................................................3 RIVERS INLET ............................................................................................................................................................5 BURKE CHANNEL ......................................................................................................................................................8 SOUTH BENTINCK ARM ...........................................................................................................................................11 DEAN CHANNEL ......................................................................................................................................................12 ROSCOE INLET .........................................................................................................................................................13 PORT BLACKNEY .....................................................................................................................................................15 TOLMIE CHANNEL ...................................................................................................................................................17 SPIDER ANCHORAGE................................................................................................................................................20 KILDIDT SOUND.......................................................................................................................................................22 BROUGHTON STRAIT ...............................................................................................................................................24 DISCUSSION.............................................................................................................................................................25 BUTTER CLAMS .......................................................................................................................................................25 LITTLENECK CLAMS ................................................................................................................................................25 MANILA CLAMS.......................................................................................................................................................26 VARNISH CLAMS .....................................................................................................................................................28 OLYMPIA OYSTERS ..................................................................................................................................................28 OTHER SPECIES .......................................................................................................................................................29 PLANKTON TOWS ....................................................................................................................................................30 ACKNOWLEDGEMENTS ......................................................................................................................................30 REFERENCES ..........................................................................................................................................................30

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LIST OF TABLES TABLE 1. LOCATION OF BEACHES SAMPLED DURING EXPLORATORY INTERTIDAL BIVALVE SURVEYS IN BRITISH COLUMBIA, JUNE 2004. ......................................................................................................................................33 TABLE 2. PHYSICAL DESCRIPTION OF BEACHES VISITED DURING EXPLORATORY INTERTIDAL BIVALVE SURVEYS IN BRITISH COLUMBIA, 2004...................................................................................................................................34 TABLE 3. CLAM DENSITIES (CLAMS M-2) BY SPECIES FROM EXPLORATORY INTERTIDAL BIVALVE SURVEYS IN BRITISH COLUMBIA, JUNE 2004. ......................................................................................................................................52 TABLE 4. DATE, TIME AND LOCATION OF PLANKTON TOWS CONDUCTED DURING EXPLORATORY INTERTIDAL BIVALVE SURVEYS, JUNE 2004. .........................................................................................................................................54

LIST OF FIGURES FIGURE 1. LANDINGS (T) AND VALUE ($CDN) OF INTERTIDAL CLAMS FROM BRITISH COLUMBIA COMMERCIAL FISHERIES, 1970-2001.........................................................................................................................................55 FIGURE 2. LANDINGS OF MANILA CLAMS (T) FROM PACIFIC FISHERIES MANAGEMENT AREA 7, 1992/1993 TO 2002/2003 SEASONS............................................................................................................................................56 FIGURE 3. GENERAL LOCATION OF EXPLORATORY INTERTIDAL BIVALVE SURVEYS IN BRITISH COLUMBIA, JUNE 2-19, 2004. ..................................................................................................................................................................57 FIGURE 4. LOCATIONS OF BEACHES SURVEYED IN SMITH SOUND, JUNE 3, 2004..........................................................58 FIGURE 5. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED AT INDIAN ISLAND, SMITH SOUND, JUNE 3, 2004.................................................................................................................59 FIGURE 6. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED IN BROAD BAY, SMITH SOUND, JUNE 3, 2004......................................................................................................................60 FIGURE 7. MEAN LENGTH-AT-ANNULUS OF BUTTER CLAMS COLLECTED AT INDIAN ISLAND, SMITH SOUND, JUNE 3, 2004. ..................................................................................................................................................................61 FIGURE 8. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF LITTLENECK CLAMS COLLECTED AT INDIAN ISLAND, SMITH SOUND, JUNE 3, 2004.....................................................................................................62 FIGURE 9. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF LITTLENECK CLAMS COLLECTED IN BROAD BAY, SMITH SOUND, JUNE 3, 2004. ........................................................................................................63 FIGURE 10. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF MANILA CLAMS COLLECTED AT INDIAN ISLAND, SMITH SOUND, JUNE 3, 2004.....................................................................................................64 FIGURE 11. MEAN LENGTH-AT-ANNULUS OF LIVE MANILA CLAMS (TOP) AND DEAD MANILA SHELL (BOTTOM) COLLECTED AT INDIAN ISLAND, SMITH SOUND, JUNE 3, 2004. ...........................................................................65 FIGURE 12. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF SOFTSHELLS COLLECTED AT INDIAN ISLAND, SMITH SOUND, JUNE 3, 2004.................................................................................................................66 FIGURE 13. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF SOFTSHELLS COLLECTED IN BROAD BAY, SMITH SOUND, JUNE 3, 2004......................................................................................................................67 FIGURE 14. MEAN LENGTH-AT-ANNULUS OF SOFTSHELLS COLLECTED AT INDIAN ISLAND (TOP PANEL) AND BROAD BAY (BOTTOM PANEL), SMITH SOUND, JUNE 3, 2004..........................................................................................68 FIGURE 15. LOCATION OF BEACHES SURVEYED IN RIVERS INLET, JUNE 4-5, 2004.......................................................69 FIGURE 16. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED AT THE HEAD OF KLAQUAEK CHANNEL, RIVERS INLET, JUNE 4, 2004. ...........................................................................70 FIGURE 17. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED AT FURY ISLAND, RIVERS INLET, JUNE 4, 2004. ................................................................................................................71 FIGURE 18. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED IN BIG FRYPAN BAY, RIVERS INLET, JUNE 4, 2004. .......................................................................................................72 FIGURE 19. MEAN LENGTH-AT-ANNULUS OF BUTTER CLAMS COLLECTED AT FURY ISLAND, RIVERS INLET, JUNE 4, 2004. ..................................................................................................................................................................73 FIGURE 20. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF LITTLENECK CLAMS COLLECTED AT THE HEAD OF KLAQUAEK CHANNEL, RIVERS INLET, JUNE 4, 2004. ....................................................................74

v FIGURE 21. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF LITTLENECK CLAMS COLLECTED AT FURY ISLAND, RIVERS INLET, JUNE 4, 2004........................................................................................................75 FIGURE 22. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF LITTLENECK CLAMS COLLECTED IN BIG FRYPAN BAY, RIVERS INLET, JUNE 4, 2004. .......................................................................................................76 FIGURE 23. MEAN LENGTH-AT-ANNULUS OF LITTLENECK CLAMS COLLECTED AT FURY ISLAND, RIVERS INLET, JUNE 4, 2004................................................................................................................................................................77 FIGURE 24. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF SOFTSHELLS COLLECTED AT THE HEAD OF KLAQUAEK CHANNEL, RIVERS INLET, JUNE 4, 2004......................................................................................78 FIGURE 25. MEAN LENGTH-AT-ANNULUS OF SOFTSHELLS COLLECTED AT THE HEAD OF KLAQUAEK CHANNEL, RIVERS INLET, JUNE 4, 2004............................................................................................................................................79 FIGURE 26. HEIGHT (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF COCKLES COLLECTED AT FURY ISLAND, RIVERS INLET, JUNE 4, 2004. ..............................................................................................................................80 FIGURE 27. MEAN HEIGHT-AT-ANNULUS OF COCKLES COLLECTED AT FURY ISLAND, RIVERS INLET, JUNE 4, 2004....81 FIGURE 28. LOCATION OF BEACHES SURVEYED IN BURKE CHANNEL, JUNE 6, 2004. ...................................................82 FIGURE 29. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED AT EDMUND POINT, BURKE CHANNEL, JUNE 6, 2004...............................................................................................83 FIGURE 30. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED IN FOUGNER BAY, BURKE CHANNEL, JUNE 4, 2004. ...............................................................................................84 FIGURE 31. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED AT KING ISLAND 2, BURKE CHANNEL, JUNE 4, 2004.........................................................................................................85 FIGURE 32. MEAN LENGTH-AT-ANNULUS OF BUTTER CLAMS COLLECTED AT EDMUND POINT (TOP) AND IN FOUGNER BAY (BOTTOM), BURKE CHANNEL, JUNE 6, 2004. ..............................................................................................86 FIGURE 33. MEAN LENGTH-AT-ANNULUS OF BUTTER CLAMS COLLECTED AT KING ISLAND 1 (TOP) AND KING ISLAND 2 (BOTTOM), BURKE CHANNEL, JUNE 6, 2004. ......................................................................................................87 FIGURE 34. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF LITTLENECK CLAMS COLLECTED IN FOUGNER BAY, BURKE CHANNEL, JUNE 6, 2004. ...............................................................................................88 FIGURE 35. MEAN LENGTH-AT-ANNULUS OF DEAD MANILA CLAM SHELL COLLECTED AT EDMUND POINT, BURKE CHANNEL, JUNE 6, 2004. ....................................................................................................................................89 FIGURE 36. LOCATION OF BEACHES SURVEYED IN SOUTH BENTINCK ARM, JUNE 7, 2004...........................................90 FIGURE 37. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BALTIC MACOMAS COLLECTED AT THE HEAD OF SOUTH BENTINCK ARM, JUNE 7, 2004..................................................................................................91 FIGURE 38. LENGTH FREQUENCY BY AGE CLASS OF BALTIC MACOMAS COLLECTED AT THE HEAD OF SOUTH BENTINCK ARM, JUNE 7, 2004. ............................................................................................................................................92 FIGURE 39. LOCATION OF BEACHES SURVEYED IN DEAN CHANNEL, JUNE 8, 2004. .....................................................93 FIGURE 40. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF SOFTSHELLS COLLECTED IN ELCHO HARBOUR, DEAN CHANNEL, JUNE 8, 2004. ........................................................................................................94 FIGURE 41. MEAN LENGTH-AT-ANNULUS OF SOFTSHELLS COLLECTED IN ELCHO HARBOUR, DEAN CHANNEL, JUNE 8, 2004. ..................................................................................................................................................................95 FIGURE 42. LOCATION OF BEACHES SURVEYED IN ROSCOE INLET, JUNE 9, 2004.........................................................96 FIGURE 43. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF MANILA CLAMS COLLECTED IN RIPLEY BAY, ROSCOE INLET, JUNE 9, 2004.....................................................................................................................97 FIGURE 44. MEAN LENGTH-AT-ANNULUS OF MANILA CLAMS COLLECTED IN RIPLEY BAY (TOP PANEL) AND MANILA CLAM SHELLS COLLECTED IN CLATSE BAY (BOTTOM PANEL), ROSCOE INLET, JUNE 9, 2004..............................98 FIGURE 45. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF SOFTSHELLS COLLECTED IN SHACK BAY, ROSCOE INLET, JUNE 9, 2004.....................................................................................................................99 FIGURE 46. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF SOFTSHELLS COLLECTED IN RIPLEY BAY, ROSCOE INLET, JUNE 9, 2004...................................................................................................................100 FIGURE 47. MEAN LENGTH-AT-ANNULUS OF SOFTSHELLS COLLECTED IN SHACK BAY (TOP PANEL) AND RIPLEY BAY (BOTTOM PANEL), ROSCOE INLET, JUNE 9, 2004...............................................................................................101 FIGURE 48. LOCATION OF BEACHES SURVEYED IN PORT BLACKNEY, JUNE 14, 2004.................................................102 FIGURE 49. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED IN OLIVER COVE, PORT BLACKNEY, JUNE 14, 2004...........................................................................................................103 FIGURE 50. MEAN LENGTH-AT-ANNULUS OF BUTTER CLAMS COLLECTED IN OLIVER COVE, PORT BLACKNEY, JUNE 14, 2004. ................................................................................................................................................................104 FIGURE 51. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF LITTLENECK CLAMS COLLECTED IN BOAT INLET, PORT BLACKNEY, JUNE 24, 2004.................................................................................................105

vi FIGURE 52. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF LITTLENECK CLAMS COLLECTED IN OLIVER COVE, PORT BLACKNEY, JUNE 14, 2004..............................................................................................106 FIGURE 53. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF MANILA CLAMS COLLECTED IN BOAT INLET, PORT BLACKNEY, JUNE 14, 2004...........................................................................................................107 FIGURE 54. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF MANILA CLAMS COLLECTED IN PASSAGE COVE, PORT BLACKNEY, JUNE 14, 2004............................................................................................108 FIGURE 55. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF MANILA CLAMS COLLECTED IN OLIVER COVE, PORT BLACKNEY, JUNE 14, 2004...........................................................................................................109 FIGURE 56. MEAN LENGTH-AT-ANNULUS OF MANILA CLAMS COLLECTED IN BOAT INLET (TOP) AND PASSAGE COVE (BOTTOM), PORT BLACKNEY, JUNE 14, 2004. ...................................................................................................110 FIGURE 57. MEAN LENGTH-AT-ANNULUS OF MANILA CLAMS COLLECTED IN OLIVER COVE, PORT BLACKNEY, JUNE 14, 2004............................................................................................................................................................111 FIGURE 58. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF SOFTSHELLS COLLECTED IN PASSAGE COVE, PORT BLACKNEY, JUNE 14, 2004...........................................................................................................112 FIGURE 59. MEAN LENGTH-AT-ANNULUS OF SOFTSHELLS COLLECTED IN PASSAGE COVE, PORT BLACKNEY, JUNE 14, 2004. ................................................................................................................................................................113 FIGURE 60. LOCATION OF BEACHES SURVEYED IN TOLMIE CHANNEL, JUNE 15-16, 2004..........................................114 FIGURE 61. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED IN ALEXANDER INLET, TOLMIE CHANNEL, JUNE 15, 2004. ...................................................................................115 FIGURE 62. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED IN BROWN COVE, TOLMIE CHANNEL, JUNE 15, 2004. ........................................................................................................116 FIGURE 63. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED AT TOLMIE CHANNEL 1, TOLMIE CHANNEL, JUNE 15, 2004................................................................................................117 FIGURE 64. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED AT TOLMIE CHANNEL 2, TOLMIE CHANNEL, JUNE 16, 2004................................................................................................118 FIGURE 65. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED AT FLAT POINT, TOLMIE CHANNEL, JUNE 16, 2004.........................................................................................................119 FIGURE 66. MEAN LENGTH-AT-ANNULUS OF BUTTER CLAMS COLLECTED IN ALEXANDER INLET (TOP) AND BROWN COVE (BOTTOM) , TOLMIE CHANNEL, JUNE 15, 2004........................................................................................120 FIGURE 67. MEAN LENGTH-AT-ANNULUS OF BUTTER CLAMS COLLECTED AT TOLMIE CHANNEL 1, TOLMIE CHANNEL, JUNE 15, 2004...................................................................................................................................................121 FIGURE 68. MEAN LENGTH-AT-ANNULUS OF BUTTER CLAMS COLLECTED IN HIGH DENSITY AREAS (TOP) AND LOW DENSITY AREAS (BOTTOM) OF TOLMIE CHANNEL 2, TOLMIE CHANNEL, JUNE 16, 2004. ..................................122 FIGURE 69. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF LITTLENECK CLAMS COLLECTED IN ALEXANDER INLET, TOLMIE CHANNEL, JUNE 15, 2004. ...................................................................................123 FIGURE 70. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF LITTLENECK CLAMS COLLECTED AT TOLMIE CHANNEL 1, TOLMIE CHANNEL, JUNE 15, 2004...................................................................................124 FIGURE 71. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF LITTLENECK CLAMS COLLECTED AT TOLMIE CHANNEL 2, TOLMIE CHANNEL, JUNE 16, 2004...................................................................................125 FIGURE 72. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF LITTLENECK CLAMS COLLECTED AT FLAT POINT, TOLMIE CHANNEL, JUNE 16, 2004. ..............................................................................................126 FIGURE 73. LOCATIONS OF BEACHES SURVEYED IN SPIDER ANCHORAGE, JUNE 17, 2004. ........................................127 FIGURE 74. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED AT HURRICANE ISLAND 1, SPIDER CHANNEL, JUNE 17, 2004.................................................................................128 FIGURE 75. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED AT HURRICANE ISLAND 4, SPIDER ANCHORAGE, JUNE 17, 2004. ...........................................................................129 FIGURE 76. MEAN LENGTH-AT-ANNULUS OF BUTTER CLAMS COLLECTED IN SPIDER ANCHORAGE, JUNE 17, 2004. ..130 FIGURE 77. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF LITTLENECK CLAMS COLLECTED AT HUNTER ISLAND, SPIDER ANCHORAGE, JUNE 17, 2004. ...................................................................................131 FIGURE 78. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF MANILA CLAMS COLLECTED AT HUNTER ISLAND, SPIDER ANCHORAGE, JUNE 17, 2004. ...................................................................................132 FIGURE 79. MEAN LENGTH-AT-ANNULUS OF MANILA CLAMS COLLECTED IN SPIDER ANCHORAGE, JUNE 17, 2004. .133 FIGURE 80. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF SOFTSHELLS COLLECTED AT HURRICANE ISLAND 1, SPIDER ANCHORAGE, JUNE 17, 2004. ...........................................................................134 FIGURE 81. MEAN LENGTH-AT-ANNULUS OF SOFTSHELLS COLLECTED IN SPIDER ANCHORAGE, JUNE 17, 2004........135 FIGURE 82. LOCATION OF BEACHES SURVEYED IN KILDIDT SOUND, JUNE 18, 2004. .................................................136

vii FIGURE 83. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF BUTTER CLAMS COLLECTED AT WATT BAY 1, JUNE 18, 2004. ......................................................................................................................................137 FIGURE 84. MEAN LENGTH-AT-ANNULUS OF BUTTER CLAMS COLLECTED AT WATT BAY 1, KILDIDT SOUND, JUNE 18, 2004. ................................................................................................................................................................138 FIGURE 85. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF LITTLENECK CLAMS COLLECTED AT WATT BAY 1, JUNE 18, 2004. ...........................................................................................................................139 FIGURE 86. LENGTH (TOP) AND AGE (BOTTOM) FREQUENCY DISTRIBUTIONS OF MANILA CLAMS COLLECTED IN KILDIDT SOUND, JUNE18, 2004. .......................................................................................................................140 FIGURE 87. MEAN LENGTH-AT-ANNULUS OF MANILA CLAMS COLLECTED IN KILDIDT SOUND, JUNE 18, 2004. ........141 FIGURE 88. LOCATION OF BEACH SURVEYED IN BROUGHTON STRAIT, JUNE 19, 2004...............................................142

LIST OF APPENDICES APPENDIX 1. COMMON AND SCIENTIFIC NAMES OF SPECIES RECORDED DURING EXPLORATORY INTERTIDAL BIVALVE SURVEYS IN BRITISH COLUMBIA, JUNE 2004. ...................................................................................................143 APPENDIX 2. DATA COLLECTION FORM USED DURING EXPLORATORY INTERTIDAL BIVALVE SURVEYS IN BRITISH COLUMBIA, JUNE 2004. ....................................................................................................................................144

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ABSTRACT Gillespie, G.E. and Bourne, N.F. 2005. Exploratory intertidal bivalve surveys in British Columbia – 2004. Can. Manuscr. Rep. Fish. Aquat. Sci.2734: ix + 144 p.

Results of exploratory intertidal clam surveys carried out in June 2004 to assess populations of commercially important clams, exotic varnish clams, Nuttallia obscurata, and native Olympia oysters, Ostrea conchaphila, on selected beaches in British Columbia (B.C.) are presented. These surveys were a continuation of exploratory clam surveys begun in 1990 to assess intertidal clam resources in the North and Central Coasts. These surveys were expanded to include exploratory work to map dispersal of the exotic varnish clam, and to map distribution of the native Olympia oyster. Manila clam populations were sparse in Smith Sound, Rivers Inlet, Spider Anchorage and Kildidt Sound. Manila clams were not found in Burke, Dean and Tolmie Channels, nor in South Bentinck Arm. Manila clams were present in Roscoe Inlet and abundant in Port Blackney. Growth of Manila clams was generally slow in the North Coast relative to South Coast populations. Varnish clams were not found in the North Coast, other than a pair of dead shells found at Indian Island in Smith Sound. This is the first evidence of this exotic species in the North Coast, and data accumulated to date suggest that the species is dispersing northward through Johnstone and Queen Charlotte Straits and could continue to spread northward. Additional biological data were collected for littleneck and butter clams, softshells and cockles. Distribution and abundance data were collected incidentally for horse clams and macomas, and size, age and growth data were collected for a population of Baltic macomas in South Bentinck Arm. Plankton tows done in most locations indicated low numbers of bivalve larvae.

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RÉSUMÉ Gillespie, G.E. and Bourne, N.F. 2005. Exploratory intertidal bivalve surveys in British Columbia – 2004. Can. Manuscr. Rep. Fish. Aquat. Sci.2734: ix + 144 p. Nous présentons ici les résultats des relevés exploratoires réalisés en juin 2004 pour évaluer l'état des populations d'espèces commercialement importantes de bivalves fouisseurs intertidaux - palourdes, nuttallies obscures (Nuttallia obscurata) et huîtres plates du Pacifique (Ostrea conchaphila), sur certaines plages de Colombie-Britannique. Ces relevés prolongeaient les relevés exploratoires des bivalves commencés en 1990 pour évaluer les ressources coquillières le long de la côte Nord et de la côte centrale. Ces relevés ont été étendus pour inclure des travaux exploratoires visant à cartographier la dispersion de la Nuttallie obscure et la distribution de l’Huître plate du Pacifique. Les populations de palourdes japonaises étaient clairsemées dans l’inlet Rivers et les baies Smith, Spider Anchorage et Kildidt. Aucune palourde japonaise n’a été observée dans les passages Burke, Dean et Tolmie ni dans le bras South Bentinck. Le mollusque était par contre présent dans l’inlet Roscoe et abondant dans la baie Port Blackney. La croissance des palourdes japonaises était généralement lente le long de la côte Nord par rapport aux taux observés sur la côte Sud. Aucune nuttallie obscure n’a été trouvée sur la côte Nord, mis à part une paire de coquille vide trouvée dans la baie Smith, sur l’île Indian. Il s’agit du premier signe de présence de cette espèce exotique sur la côte Nord et les données recueillies à ce jour indiquent que l’espèce se répand actuellement vers le nord à travers les détroits de Johnstone et de la Reine-Charlotte et qu’elle pourrait continuer à se répandre dans cette direction. Des données biologiques supplémentaires ont été recueillies pour la Palourde du Pacifique et la Palourde jaune, la Mye et la Coque européenne. Des données de distribution et d’abondances ont été recueillies en passant pour la Fausse-mactre et la Macoma tandis que des données sur la taille, l’âge et la croissance ont également été recueillies pour une population de macomas baltiques dans le bras South Bentinck. Sur la plupart des sites, les remorquages de plancton n’ont révélé qu’un faible nombre de larves de bivalves.

INTRODUCTION The present survey was part of a program begun in 1990 to assess intertidal bivalve resources in British Columbia (Bourne and Cawdell 1992; Bourne et al. 1994; Bourne and Heritage 1997; Heritage et al. 1998; Gillespie and Bourne 1998, 2000, in press; Gillespie et al. 2004). Initially these surveys focused on studies of the dispersal and extent of populations of Manila clams, Venerupis philippinarum, in coastal waters of northern B.C., as this species has dominated commercial clam landings in B.C. since the early 1980’s (Figure 1). One result of these surveys was the development of a commercial fishery for Manila clams in the Bella Bella area in 1992 that has continued to the present day with annual landings ranging from 25-115 t (Gillespie et al. 1999a, 2001a; Figure 2). Since the late 1990’s these surveys have become more extensive and inclusive. Surveys have been extended to include other areas, including Queen Charlotte Strait, Johnstone Strait, the west coast of Vancouver Island and the Queen Charlotte Islands. The scope of the surveys has also been extended to include assessment of populations of species that are utilized in the present commercial fishery in B.C. or have potential in future fisheries. These species include; butter clams, Saxidomus giganteus, littleneck clams, Protothaca staminea, cockles, Clinocardium nuttallii, softshells, Mya arenaria, horse clams, Tresus capax, and the native Olympia oyster, Ostrea conchaphila. In recent years there has been increased interest by industry to harvest these species and this includes harvest in the North Coast. If fisheries for these species develop in the North Coast, it is essential that sufficient biological information is available for efficient management of these resources. In addition to collection of information on the above stocks, incidental information has been gathered on other species to add to our knowledge of the distribution and abundance of intertidal fauna in B.C.1 Of particular interest in recent surveys has been collection of information on the distribution and abundance of stocks of the varnish clam, Nuttallia obscurata, which was introduced into B.C. in the late 1980’s and has since spread rapidly northward (Gillespie et al. 1999b, 2001b). The present survey took place from June 3-19, 2004 and extended from Broughton Strait in the south to Tolmie Channel in the north. It included re-visiting some areas to determine if there had been pronounced changes in intertidal clam populations, particularly populations of Manila clams, along with surveys of new areas to assess if Manila clams were present, assess the state of such populations and to gather information on the extent and state of populations of other clam species.

1

Common and scientific names for all species recorded are in Appendix 1.

2

METHODS Methods used in the surveys have changed little since they began in 1990 and have been described previously (Bourne and Cawdell 1992; Bourne et al. 1994; Bourne and Heritage 1997; Heritage et al. 1998; Gillespie and Bourne 1998, 2000). Beaches were selected for survey from charts, as well as from previous experience, DFO clam atlases (Harbo et al. 1997), contract reports (Aquametrix Research and Axys Environmental Consulting 1997, Peacock et al. 1998), information from Fisheries Officers and local inhabitants and from requests by industry. A guiding principal in this work has been to maximize the number of beaches explored during a tide, rather than survey one or two beaches in detail (fide Gillespie and Kronlund 1999). Results of these surveys give estimates of clam distribution and abundance in surveyed areas and not statistically rigorous stock estimates. The exact location of each beach was determined from charts and by GPS. A brief survey was made of each beach visited to assess the presence or absence of intertidal clams and determine the area of the clam bearing part of the beach prior to sampling. Clam areas were estimated by digging exploratory holes to delimit clam distribution. Slope of the beach and substrate type were recorded. The high tide line was surveyed for drift shell of intertidal clams and large rocks which are used by birds to drop and break clams were examined for shell fragments. In the past, evidence of the presence of Manila clams has been determined with these latter assessment methods. When aggregations of clams were found, quadrats of 0.25 m2 and 1.00 m2 were dug. Quadrats in the upper portion of the intertidal zone (0.25m2 targeting mainly on Manila clams and to a lesser extent on littleneck clams) were dug with a clam scraper to a depth of about 15 cm. Quadrats lower on the beach (1 m2 targeting mainly on butter clams and to a lesser extent on littleneck clams) were dug with a potato fork to a depth of about 35 cm. When Manila clams were present at very low abundance, quadrat size was expanded until sufficient clams for biological sampling were obtained (preferably more than 20 clams), or until no more Manilas could be found, and final quadrat size was estimated and recorded. In all cases, the dug substrate was reworked back into the quadrat through the fingers to detect clams missed when the quadrat was initially dug. All dug clams were washed, bagged and labeled for processing. Additional information was gathered on incidental species of invertebrates found on beaches and some specimens were collected for further identification. A new innovation for the present survey was the design and use of a beach reporting form (Appendix 2) that greatly facilitated collection of data and transfer of this information to the computer. Total length of each clam (longest anterior-posterior length, TL) was measured to the nearest mm with vernier calipers. Shell height, from the umbo to the ventral shell margin, was measured for cockles. Ages were determined by counting annuli (Quayle and Bourne 1972). Length/height and age frequency distributions were determined and graphed. Length/height at annulus was measured for a representative sample of Manilas,

3 littlenecks, butters, softshells and cockles. This provided length/height and age distribution and growth rate information for these species in each area surveyed. Surface water temperature at a depth of 20 cm was recorded with a standard hand-held thermometer in each area. A five minute surface plankton tow using a 40 cm diameter frame and 70 µm mesh was made in each area to determine the presence of any bivalve larvae.

RESULTS Forty-three beaches were surveyed in 11 areas in 2004 (Table 1). The survey area extended from Broughton Strait in the south to Tolmie Channel in the north (Figure 3). Smith Sound Smith Sound opens onto Queen Charlotte Sound and extends northeast to the mouths of Smith and Boswell Inlets. Although partially protected by a number of islands near its mouth, there is usually a considerable swell from the open ocean and clam beaches are restricted to protected bays and channels. Modest harvest of butter clams occurred in Smith Sound until the area was closed in the mid 1960’s because of chronic low levels of Paralytic Shellfish Poisoning (PSP) in some North Coast butter clam populations (Quayle 1966). Smith Sound was surveyed in 1993; sampling focused on assessment of intertidal clams on beaches at the mouth of the sound (Bourne and Heritage 1997). At that time butter and littleneck clams were found in abundance on selected beaches and Manila clams were found on three beaches. Most Manila clams were large and growth was slow. Beach surveys conducted in 1996 (Aquametrix Research and Axys Environmental Consulting 1997) found Manila clams or shell at several beaches in Smith Sound and Smith and Boswell Inlets, but did not estimate densities or collect biological samples. It was of interest to resurvey this area to determine if the population of Manila clams had increased since 1993 to the point where it could support commercial harvest. Another important focus of the survey was to determine if varnish clams had spread this far north. Physical Description of Beaches Four beaches that were sampled in 1993 (Indian Island, Fly Basin, Broad Bay and the north side of Greaves Island) were surveyed in 2004 (Figure 4). Beaches 1, 2, 3, and 4 in 2004 were beaches 9, 6, 5 and 3 respectively in 1993 (Bourne and Heritage 1997). Broad Bay and Greaves Island were surveyed by Aquametrix Research and Axys Environmental Consulting (1997); their beach codes SC_013 and SC_011, respectively.

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Area of these four beaches ranged in size from 0.5-3 ha, the clam bearing area from 20 ha in area (Table 2). Slope of all three beaches was low. Substrate of all three beaches was packed sand-mud with mud and silt on the surface, Taleomy Narrows had some coarse gravel. Wood debris occurred on some beaches and the beaches had probably been used in past logging operations. Substrate of all three beaches was unsuitable as bivalve habitat. Bivalve Populations No evidence of butter, littleneck, Manila or varnish clams was found on the three beaches, neither live animals or dead shell. Even evidence of littleneck clams, that are ubiquitous throughout the northern area and occur in virtually all locations, was not found. Unsuitable oceanographic conditions and poor habitat eliminated the possibility of establishing significant commercial bivalve populations. The small bivalve Macoma balthica occurred in large numbers on the beach at the head of South Bentinck Arm. A quadrat was dug and density was determined to be 2,378 clams m-2 (Table 3). Shell length ranged from 6-17 mm (Figure 37). Distinct lines on the shells of these clams were assumed to be annual rings and an assessment showed the clams ranged in age from 1-4 years, most were 3 year olds (Figure 37). A length frequency distribution by age class showed that age 1 clams ranged from 6-10 mm with a mode a 7 mm, age 2 from 9-14 mm with a mode at 10 mm, age 3 from 10-16 mm with a mode at 13-14 mm, and age 4 from 12-17 mm with a mode at 15-16 mm (Figure 38). The only other bivalve seen in South Bentinck Arm was blue mussel, which was found at all three beaches (Table 2).

12 Other Observations A five-minute plankton tow taken in Taleomy Narrows (Table 4) contained no bivalve larvae or phytoplankton. The tow contained only silt particles and debris. Surface water temperatures off the three beaches were low and ranged from 12-14°C. Temperature was only 8°C in the Noeick River that emptied into the arm at Taleomy Narrows. Dean Channel Dean Channel runs 85 km north from the Fisher Channel to the estuary of the Kimsquit River. It is typical of many channels and inlets in the North Coast; narrow and steep sloped with few intertidal beaches. There is also a strong flow of surface water southward down the channel that may prevent a northward distribution of bivalve larvae. There is evidence of past logging activity along various parts of the channel. In 2001, sampling was undertaken in Fisher Channel and at the northern end of Dean Channel, but sampling was not done between these areas (Gillespie et al. 2004). Manila clams were found in the Fisher Channel area but not at the head of Dean Channel. No bivalves were reported after limited sampling in 1996 in Jenny Inlet and Elcho Harbour (Aquametrix Research and Axys Environmental Consulting 1997). In the present survey, sampling was undertaken approximately in the mid Dean Channel area to assess bivalve populations and determine if Manila clams extended that far up the channel. Two beaches were sampled, one at the head of Elcho Harbour and the other on the east side of Dean Channel across from Elcho Harbour (King Island 3). Physical Description of Beaches The two beaches ranged in area from 2-4 ha with 0.5-2 ha of clam bearing area (Table 2). Slopes were low to moderate. Both beaches were very rocky but had some patches of sand-mud substrate interspersed among the rock and boulders; digging was difficult. There was a heavy cover of rockweed over much of the beaches. Bivalve Populations Numerous exploratory scratches were made but no quadrats were dug on either beach because of the limited amount of suitable habitat and the lack of bivalves. Butter clam shell was found at King Island 3, but no littleneck shell was found on either beach (Table 2). No evidence of Manila or varnish clams, live animals or dead shell, was found on either beach. Baltic macomas were common on both beaches.

13 Softshells were moderately abundant at Elcho Harbour; although no quadrats were dug, abundance was estimated to be about 20 clams m-2 when the total estimated area of scratches was considered. Some dead softshell shell was found at King Island 3. A pooled sample of softshells from the beach in Elcho Harbour ranged in size from 22-88 mm and in age from 1-9 years (Figure 40). Measurements of annuli showed that growth was moderate and a size of 50 mm TL was attained in about 4 years (Figure 41). Other Observations A five-minute plankton tow taken in Dean Channel (Table 4) contained relatively few mussel larvae, with some in umbone stage, and one softshell larva. Surface water temperature was 15°C off both beaches (Table 2). Roscoe Inlet Roscoe Inlet lies to the east of Briggs Inlet and extends northward into the Coldwell Peninsula for about 34 km (Figure 42). It is typical of many inlets in the North Coast, narrow with steep slopes and few intertidal beaches. Most of the area surrounding Roscoe Inlet had been sampled previously: Seaforth-Spiller and Return Channels in 1993 (Bourne et al. 1994); Troup Passage, Spiller and Bullock Channels in 1994 (Heritage et al. 1998); and Fisher Channel and Briggs Inlet in 2002 (Gillespie and Bourne 2005). Surveys undertaken in 1996 by Aquametrix Research and Axys Environmental Consulting (1997) reported Manila clams from several beaches in the inlet, but did not estimate densities or collect biological samples. The goal of the present survey was to complete sampling in the area by surveying this inlet. In the present survey, three beaches in Clatse Bay, Shack Bay and Ripley Bay were sampled (Table 1). Physical Description of Beaches The three beaches ranged in area from about 1-1.5 ha with clam bearing areas of 0.2-0.3 ha (Table 2). Slopes were low to moderate. There was considerable rock on all three beaches with pockets of sand-mud substrate interspersed in between. There were more extensive sand-mud areas towards the low tide line. Rockweed was abundant, as were blue mussels.

14 Bivalve Populations Numerous exploratory scratches were made in Clatse and Shack Bays, but quadrat sampling was only undertaken in Ripley Bay (Table 3). All three beaches were rocky and it was difficult to dig quadrats in suitable habitat interspersed between rocks. Butter and Littleneck Clams No live butter or littlenecks or dead shell were found on the three beaches. Both species, particularly littlenecks, may have been present in low numbers. Manila Clams Live Manila clams and dead shells were found on all three beaches. Quadrats dug in Ripley Bay had densities that ranged from 0-28 clam m-2 (Table 3). Shell length of theses clams ranged from 24-45 mm and age from 3-8 years (Figure 43) indicating limited recruitment in recent years. Growth was measured from live clams collected in Ripley Bay and a sample of dead shell from Clatse Bay3 (Figure 44). Growth of live Manila clams from random scratches in Ripley Bay was slow; it required about 5 years to attain a size of 38 mm TL. Growth measured from the dead shell was also slow; it required about 6 years to attain a size of 38 mm TL. Differences between the samples could be due to location or time (we do not know how long ago the Manilas died in Clatse Bay), but no explanation can be given for the generally slow growth rates of Manila clams in this inlet. It is doubtful if Manila clam populations in Roscoe Inlet are sufficient to be of interest to the commercial industry. Other Species Softshells were common on all three beaches. Softshells from random scratches were collected at beach 2, Shack Bay. Size ranged from 36-85 mm TL and age from 210 years (Figure 45). At Ripley Bay, densities ranged from 0-56 clams m-2 (Table 3). Size ranged from 37-84 mm TL and age from 2-8 years (Figure 46). Growth was reasonable at both locations; it required about 4 years to attain a size of 50 mm TL (Figure 47). Live cockles and shell were found on all three beaches. Baltic macomas were found on all three beaches, and were common in Clatse and Shack Bays.

3

Surveys in 1996 reported Manila clams to be abundant in Clatse Bay (Aquametrix Research and Axys Environmental Consulting 1997) at their beach SC_137. We examined the beach at the head of the bay, their beach SC_138. Because their report was gray literature and not listed in abstract services we were unaware it existed until after our surveys were completed. We estimated growth of Manila clams in Clatse Bay from dead shells because live Manila clams were difficult to find on the beach we surveyed.

15 Other Observations A five minute surface plankton tow at Ripley Bay had large quantities of zooplankton that included ostracods (Table 4). There were few bivalve larvae; most were mussels that ranged from early straight hinge to eyed larvae. There were two littleneck larvae. Water temperatures in the inlet were warm, 16°C off all three beaches. Port Blackney The Port Blackney area lies at the confluence of Seaforth Channel and Milbanke Sound at the southern end of Mathieson Channel (Figure 48). It is well protected and lies between Cecilia Island and the Don Peninsula north of Powell Anchorage in Reid Passage. Similar to Roscoe Inlet, much of the area around Port Blackney had been sampled previously (Bourne and Cawdell 1992; Bourne et al. 1994; Heritage et al. 1998). The goal of the present work was to complete sampling in the area. A further stimulus for sampling were reports that commercial harvest of Manila clams had occurred in this area and hence it was of interest to assess the extent of Manila clam populations in the area. Peacock et al. (1998) reported Manila clams from Boat Inlet and Oliver Cove (their beaches NC_016 and NC_017), but not from Passage Cove (NC_015), nor did they estimate densities or collect biological information. Three beaches were sampled at Port Blackney; Boat Inlet, Passage Cove and Oliver Cove (Figure 48). Quadrats were dug at all three beaches (Table 3). Physical Description of Beaches The three beaches in Port Blackney ranged in area from about 0.1-1.0 ha, with most of each beach being clam bearing area (Table 2). Slope of all three beaches was low. Substrate was sand-mud to sand gravel. Rocks and boulders were present, particularly at Oliver Cove. At Boat Inlet, much of the substrate was sticky mud that made digging difficult. Substrate at the low tide line was mainly mud with eelgrass. Bivalve Populations Populations of all three species of commercial interest were present on all beaches, along with fat horse clams, cockles, softshells and pointed and bent-nose macomas (Table 2).

16 Butter Clams Butter clams were found on all three beaches and density ranged from 0-48 clams m (Table 3). There was abundant dead shell on all three beaches and undoubtedly extensive populations existed in the lower third of all three beaches. In a sample taken in Oliver Cove, size ranged from 18-84 mm TL and age from 2-13 years indicating reasonable recruitment in recent years (Figure 49). Growth was slow and it required about 8 years to attain a shell length of 63 mm (Figure 50). -2

Littleneck Clams Evidence of littleneck clams in the form of dead shell was found on all three beaches, but live calms were only collected in quadrats dug in Boat Inlet and Oliver Cove. Here density ranged from 0-56 clams m-2 (Table 3). At Boat Inlet shell length ranged from 26-56 mm and age from 3-10 years (Figure 51), and in Oliver Cove shell length was from 13-58 mm and age from 2-11 years (Figure 52). Although many of the clams were stunted, the presence of young clams indicated recruitment in recent years. Manila Clams Manila clams were abundant in the area as shown by the amount of dead shell on the beach and the presence of live clams in quadrats. They were found in every quadrat dug on the three beaches and density ranged from 1-276 clams m-2 (Table 3). There was a preponderance of legal size clams; in total 80% were larger than 38 mm TL. At Boat Inlet, shell length ranged from 26-52 mm and age from 3-9 years (Figure 53). In Passage Cove, shell length was 18-46 mm and age 2-6 years (Figure 54), and in Oliver Cove shell length was 30-55 mm and age from 3-8 years (Figure 55). At Boat Inlet a broad range of ages were well represented. At Passage Cove most were 4- and 5-year-olds and at Oliver Cove there was a preponderance of 5- and 6-year-olds. Growth was similar but slow at all three beaches, it required 4-4.5 years to attain a shell length of 38 mm (Figure 56 and Figure 57). Populations of Manila clams in this area are sufficient to support commercial harvest.

Varnish Clams No live varnish clams or dead shell were found. Other Species Softshells were common in the area and shell was found on all three beaches (Table 2). Live animals were found in quadrats dug on all three beaches and density

17 ranged from 0-26 clams m-2 at Passage Cove (Table 3). At Passage Cove, size ranged from 19-90 mm TL and age from 1-9 years, indicating there was recruitment in recent years (Figure 58). Growth was similar to that found in other areas in the North Coast; it required about 4 years to attain a shell length of 50 mm (Figure 59). Shells of fat horse clams were found in Passage and Oliver Coves (Table 2), and one live animal was dug in a quadrat in Oliver Cove (Table 3). Cockle shell was found on all three beaches and live animals were observed in suitable habitat. One live animal was found in a quadrat dug in Oliver Cove (Table 3). Pointed macomas were found at densities of 0-16 clams m-2 in quadrats dug in Boat Inlet and Oliver Cove (Table 3). Shell of the pointed macoma was found on all three beaches, and shell of bent-nose macoma was found in Boat Inlet (Table 2). Other Observations A five minute surface plankton tow in the area (Table 4) had large quantities of phytoplankton, mainly chain forming algae including chain forming diatoms and the dinoflagellate Noctiluca scintillans. There was a lot of zooplankton, including ostracods. Very few bivalve larvae present, although some may have been tangled in the algal mass. Only mussel larvae in various stages were observed. Surface water temperature was 1112°C off the three beaches (Table 2). Tolmie Channel Tolmie Channel is typical of channels and inlets in the North Coast. It is a narrow channel that extends about 35 km north from Meyers Passage to the southern end of Graham Reach at the south end of Princess Royal Channel (Figure 60). The foreshore is steeply sloped and falls sharply to considerable depths close to shore. The intertidal area is sparse and there are few estuaries or intertidal beaches. In previous years considerable sampling was undertaken in the Finlayson and Mathieson Channel areas, primarily to assess the northward dispersal of Manila clams (Bourne and Cawdell 1992; Heritage et al. 1998; Gillespie and Bourne 1998). Results of this work showed that Manila clams occurred in the southern part of Finlayson Channel, throughout Mathieson Channel and in Bolin and Windy Bays in Sheep Passage that extends from the northern part of Mathieson Channel eastward where it joins the north end of Finlayson Channel. In 2000, the northern end of Princess Royal Channel was surveyed but no Manila clams were found, and the conclusion was they had not dispersed that far north (Gillespie et al. 2004). Peacock et al. (1998) did not report Manila clams to be present during beach surveys undertaken at Brown Cove and Flat Point (their beaches NC_127 and NC_120, respectively). The purpose of the present survey was to assess clam populations in the general area of Tolmie Channel and in particular to determine whether Manila clams were

18 present in this area (i.e., did they occur in the area between Sheep Passage and the northern part of Princess Royal Channel). Sampling was undertaken on two days (Table 1). On June 15, 2004, surveys were completed in the southern part of Tolmie Channel (Alexander Inlet, Brown Cove and Tolmie Channel 1) and on June 16 in the area between Sheep Passage and previous sampling locations in Princess Royal Channel (Tolmie Channel 2 and Flat Point). Physical Description of Beaches Three beaches were sampled in the southern part of Tolmie Channel on June 15, 2004. Area of these beaches ranged from 0.5-0.7 ha, and estimated clam bearing area was 0.2-0.5 ha (Table 2). There was considerable rock on all three beaches that made digging difficult. There were sand-shell and gravel patches interspersed among the rock that had considerable populations of clams. The lower portion of the beaches was soft mud with eelgrass. Tolmie Channel 1 was posted with DFO signs warning of health risks due to contamination or PSP so the beach was obviously a popular place for harvesting clams, probably by people from nearby Klemtu. Two beaches were surveyed in the northern part of Tolmie Channel on June 16, 2004 (Table 1). Intertidal area ranged from 0.3-1.0 ha (Table 2). These beaches were located north of Sheep Passage but south of the area sampled in 2000. There was considerable rock on both beaches. There were patches of firm sand and shell interspersed among the rocks, which supported bivalve populations. The lower part was mainly mud with eelgrass. Bivalve Populations Butter Clams Butter clams were common on all beaches in suitable habitat and density ranged from 12-184 clams m-2 in the southern end of the channel and from 30-164 clams m-2 in the northern channel (Table 3). At Alexander Inlet, shell length was 59-73 mm and age 7-12 years (Figure 61). At Brown Cove, shell length was similar to that at Alexander Inlet, 59-73 mm but there was a wider spread in ages, 5-16 years (Figure 62). Butter clams were most abundant at Tolmie Channel 1 where shell length was 15-89 mm and age ranged from 1-16 years (Figure 63). Recruitment was good at Tolmie Channel 1 and there were frequency modes at age 6 and 12. At Tolmie Channel 2, shell length ranged from 51-91 mm and age from 8-14 years (Figure 64). At Flat Point, all of the butter clams were small; length was 17-42 mm and age from 2-6 years (Figure 65). Growth rates showed growth was slow, it required about 9 years to attain a size of 63 mm TL at all three beaches (Figure 66 and Figure 67). Growth rates were calculated for butter clams found in high and low density areas at Tolmie Channel 2. In the low

19 density area a size of 63 mm TL was attained in about 8 years and in the high density area in about 9 years (Figure 68). Littleneck Clams Littleneck clams were common in suitable habitat on all beaches in Tolmie Channel and density ranged from 2-45 clams m-2 in the south and from 8-260 clams m-2 in the north (Table 3). There was considerable shell on the beaches and densities may have been higher if sampling had targeted on this species. At Alexander Inlet, shell length was 32-47 mm and age from 6-12 years (Figure 69), indicating little recruitment in recent years. At Tolmie Channel 1, shell length was 19-57 mm and age 2-11 years indicating some recruitment in recent years (Figure 70). There was considerable stunting of littlenecks at both locations. At Tolmie Channel 2, all littlenecks were large, 44-58 mm TL, and 7-12 years in age (Figure 71). At Flat Point there was a much wider spread in both shell length and age; shell length was 17-45 mm and age from 2-10 years (Figure 72). Although some stunting was observed, results at Flat Point indicated good recruitment in recent years. Manila Clams There was no evidence of Manila clams, either live animals or dead shell, on any of the beaches in the Tolmie Channel area. Manila clams have not dispersed to the lower end of Tolmie Channel from Meyers Passage or Finlayson Channel, nor northward from Sheep Channel into northern Tolmie Channel or Princess Royal Channel. Varnish Clams No evidence of live varnish clams or dead shell was found in the Tolmie Channel area. Other Species Dead shell of fat horse clams was found on beaches in both northern and southern Tolmie Channel (Table 2) and two live animals were found in a quadrat at Tolmie Channel 1 (Table 3). Cockles were found on all five beaches and were abundant at Tolmie Channel 2 and Flat Point; maximum density at the latter site was 28 clams m-2 (Table 3). Dead softshell valves were found at Alexander Inlet, but were not reported from other locations and no live animals were collected. Baltic, bent-nose and pointed macomas or their shells were observed in various combinations on all beaches (Table 2). Live truncated softshells were collected in Alexander Inlet and at Tolmie Channel 1 and shells were observed at Flat Point. Shells of large fan horsemussels were observed at Tolmie Channel 1, and live Arctic hiatella were observed at Flat Point. Dungeness crabs (newly settled juveniles, subadults and adults) were common on the lower reaches of Brown Cove and Tolmie Channel 1 and 2 (Table 2).

20 Other Observations Five minute surface plankton tows were taken in Tolmie Channel on June 15 and off Flat Point on June 16 (Table 4). Both tows had considerable algae in them; obviously there was a bloom at both locations. Most of the algae were chain forming algae, including chain forming diatoms. Desmids were present in both tows. There was little zooplankton. Very few bivalve larvae were found in either tow; all were mussel larvae in various stages of development. Surface water temperature off all five beaches was 10°C (Table 2). Spider Anchorage Spider Anchorage is a protected body of water on the southern side of Hunter Island that is surrounded by an archipelago of small islands (Figure 73). There are small pocket beaches on these islands that have populations of bivalves. The Spider Anchorage area had been surveyed previously; indeed it was the place where Manila clams were first found north of Vancouver Island (Bourne 1982). The area was extensively resurveyed in 1991 at which time Manila clams were found in several places but not in abundance (Bourne et al. 1994). Focus in the 1991 survey was to assess Manila clam population and little attention was paid to other species. The goal of the present survey was to assess bivalve populations in general and to again assess the extent of the Manila clam populations. We also sought to determine if varnish clams were present in the area since dispersal of this species may be similar to that of Manila clams. In the present survey sampling was undertaken on five beaches on the shores of Hurricane Island and one beach on Hunter Island (Figure 73). Physical Description of Beaches All six beaches surveyed in the Spider Anchorage area were pocket beaches that varied in size and clam bearing area from