PARR 2011-P-10
Are shellfish transfers a likely vector for aquatic invasive species movement from the west to the east coast of Vancouver Island?

Wild and cultured Manila clams (Venerupis philippinarum) and Pacific oysters (Crassostrea gigas) harvested on the west coast of Vancouver Island (VI) must be sent to processing plants on the east coast of the island since presently there are no commercial shellfish processing plants located on the west coast of VI.  In the past, processors have been permitted to “wet store” large quantities of harvested shellfish in the intertidal zone next to their processing plants or on aquaculture tenures, processing shellfish as time and markets allowed.  There were concerns, however, that this practice could lead to the spread of the invasive European green crab (Carcinus maenas), that currently only occurs on the west coast of VI,  and other non-indigenous aquatic invasive species (AIS) from the west to the east coast of VI. 

As a precaution, DFO added clauses to shellfish culture licences that restrict wet storage and require a visual inspection and rinsing of all harvested shellfish prior to transfer to processing plants. Although these measures have been implemented, there has been no scientific research undertaken to evaluate the effectiveness of or need for the new licence requirements. In addition to this potential vector for movement of AIS, the Canadian Food Inspection Agency (CFIA), as part of their biotoxin monitoring program, collects mussels on the west coast of VI for re-distribution along the British Columbia coastline. This presents another potential avenue for the spread of AIS, but again the risk of this particular vector has not been researched.

The project's main objective is to assess whether shellfish transferred by the shellfish industry and the CFIA's biotoxin monitoring program act as potential vectors for the spread of AIS, with particular focus on the European green crab, from the west to the east coast of VI. This project will quantify the potential risk of AIS spread from the west to east coast of VI associated with current shellfish transfer protocols by: (1) enumerating green crabs on Pacific oysters, Manila clams, and California mussels from areas with green crab populations on the west coast of VI, (2) enumerating green crabs on west-coast VI shellfish products obtained from processors, and (3) building a database of the historical numbers and weight of shellfish transferred from the west coast of VI to east-coast VI processors. Currently, more research is needed in this area to assess the risk of this particular AIS vector.

Results from the project will help inform conditions of licence for shellfish culture operators and aid in the development of scientifically-based shellfish aquaculture management zones in British Columbia.

Primary investigator:
Chris Pearce (Fisheries and Oceans Canada, Pacific Region)

Team members:
Lyanne Burgoyne (Fisheries and Oceans Canada, Pacific Region), Dan Curtis (Fisheries and Oceans Canada, Pacific Region), Graham Gillespie (Fisheries and Oceans Canada, Pacific Region), Haley Matkin (contractor), Tom Therriault (Fisheries and Oceans Canada, Pacific Region), Matt Thompson (Fisheries and Oceans Canada, Pacific Region)

Collaborators:
Canadian Food Inspection Agency (CFIA), Mac's Oysters Ltd.

Project Start: 2011
Project End: 2013

Contact:
Chris Pearce (Chris.Pearce@dfo-mpo.gc.ca)