Science Response 2018/047

Summary of Locations in British Columbia, Canada Supporting Invasive Tunicate Species and European Green Crab as of 2017

Context

Aquatic Invasive Species (AIS) can be redistributed both intentionally and unintentionally by a number of human-mediated vectors, including shellfish transfers as part of routine aquaculture operations. For example, in British Columbia, shellfish transfers are known to pose a risk of inadvertently moving invasive tunicates and European Green Crab. Although it is not possible to know the exact distribution of any AIS with complete confidence, Fisheries and Oceans Canada’s (DFO) Science Branch in Pacific Region maintains geospatial information on all survey locations and the specific locations where AIS occur as part of its Regional AIS Monitoring Program. This information, even with some uncertainties (i.e., the coastline of British Columbia has not fully been surveyed), can be useful for management and policy decisions about AIS in British Columbia. For example, maps indicating the locations of various AIS can be used by shellfish managers to help identify locations where additional management measures may be needed when aquaculture transfer applications are reviewed, thereby reducing the likelihood that AIS will be moved unintentionally.

DFO’s Aquaculture Management Division in Pacific Region has requested science advice on known high risk invasive tunicate and European Green Crab presence as well as a summary of locations that have been surveyed for these AIS. European Green Crab and four tunicate species known to occur in British Columbia are listed as Control species in the Aquatic Invasive Species (AIS) Regulations under the federal Fisheries Act.

The purpose of this Canadian Science Advisory Secretariat (CSAS) Science Response (SR) is to generate geospatial maps of locations with positive confirmation of invasive tunicates and European Green Crab, along with survey locations for these AIS. The assessment and advice arising from this SR will be used to inform the management/policy development of the British Columbia Aquaculture Regulation. It will also be used in making Pacific Aquaculture Regulatory and Introductions and Transfers license decisions. Further, data may inform ecosystem management, aquaculture siting guidelines, and/or industry best management practices, while future AIS analyses may help delineate the spatial scale at which shellfish aquaculture is managed in British Columbia (i.e., BC shellfish transfer zones versus discrete BC ecosystems (ecoregion or bay scale)).

This Science Response results from the Science Response Process of May 2018, Presence and distribution of European Green Crab and invasive tunicate species in British Columbia

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