Intertidal Clam

Four species of intertidal clams; butter, littleneck, manila, and razor clams, comprise the major portion of landings in commercial and recreational clam fisheries in British Columbia (BC). Initially, the targeted species was butter clams, which were harvested for canning at various processing facilities along the coast. Since 1971, however, strong markets and higher prices have focused the clam fishery on littleneck and manila clams, which are more acceptable on the market as fresh product. Further, manila and littleneck clams retain paralytic shellfish toxins (PSP) for a much shorter period than butter clams, adding to their appeal as a fresh product. A few other species, such as the varnish and razor clams, occasionally enter the commercial clam fishery and are utilized to a somewhat greater extent in the recreational fishery.

The clam species important to the various fisheries in B.C. include:

• Manila clam (Venerupis philippinarum)
• Native littleneck clam (Protothaca staminea)
• Butter clam (Saxidomus gigantea)
• Razor clam (Siliqua patula)
• Varnish (Savoury) clam (Nuttallia obscurata)

There are two types of commercial fisheries for intertidal clams:

• Wild commercial fishery (non-polluted beaches)
• Depuration fishery (polluted beaches)

Stock Assessment

Stock assessment activities relating to commercial fisheries for intertidal clams include:

• Collaborative survey design, sample processing and analyses for the aboriginal communal commercial and depuration fisheries. Results of which are reported to Fish Management.
• Clam collection during stock assessment surveys to identified species, number and weight, including legal and sublegal sized clams where appropriate.  From these data, abundance and biomass estimates are determined from which harvest quotas can be generated.
• Retention of biological samples from surveys to collect individual length, weight and age information in order to develop an understanding about the status of populations on particular beaches and growth patterns.
• Surveying beaches that are going to be harvested, as well as several unharvested beaches to gain a better understanding about wild recruitment processes.
• Provide data support services to Industry and First Nations groups including: confirming survey data quality, inputting data into an electronic format, selecting biological samples, providing sampling advice/training, confirming biomass estimates, and approving sampling designs.
• Inputting all clam survey data collected by the Depuration fishery into the DFO's main database.

Contacts

Clam Staff

Graham Gillespie
Tel: 250-756-7215
Graham.Gillespie@dfo-mpo.gc.ca

Jason Dunham
Tel: 250-756-7214
Jason.Dunham@dfo-mpo.gc.ca