Science Advisory Report 2010/083

Science Advice from a Risk Assessment of Northern Pike (Esox lucius) in British Columbia

Summary

• Northern Pike is a large, cool-water fish found in all northern continents under a wide range of conditions. It is not native to southern British Columbia, but an introduced population has been identified there.
• Northern Pike inhabits vegetated littoral zones and where it preys on fishes.
• Northern Pike is known to have considerable impact on native fish communities in lakes where it was introduced, particularly impacting fish communities of small, shallow lakes with extensive littoral zones.
• It is a desirable fish for anglers, which has lead to authorized and illegal introductions elsewhere.
• It prefers slow-moving waters, but is known to use streams to colonize downstream lakes when introduced higher in a watershed.
• The risk assessment evaluated the likelihood of arrival, survival, establishment and spread of Northern Pike in regions of British Columbia. It estimated the impact of widespread establishment of Northern Pike and combined the impact and probability estimates in a risk matrix to determine overall level of risk posed to aquatic communities in British Columbia.
• The risk of widespread establishment is considered to be high for the Columbia region and moderate for the Vancouver Island, Lower Mainland, Upper Fraser and Thompson regions.
• A very high impact with low uncertainty is expected in shallow lakes with extensive littoral zones.
• The overall level of risk was found to be high with a moderate uncertainty.
• This risk assessment was undertaken at a large scale. If risk posed to a particular waterbody is needed, a separate risk assessment, specific to that location should be undertaken.
• Fish are difficult to eliminate from a system once established. If deemed undesirable, Northern Pike should be prevented from becoming established.

This Science Advisory Report is from the Fisheries and Oceans Canada, Canadian Science Advisory Secretariat, regional advisory meeting of March 4-6, 2008 on Risk assessment of spiny-rayed fishes (six species).  Additional publications from this process will be posted as they become available on the DFO Science Advisory Schedule.

Complete document (PDF, 211 KB)

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