Monitoring the Invasion of Northern Pike in the Columbia River, British Columbia, Canada

Northern Pike are an invasive species in southern British Columbia. They were first detected in the Columbia River downstream of Hugh L. Keenleyside Dam in 2009 during annual electroshocking surveys. Since the first confirmed specimen was caught in 2009, Northern Pike numbers have increased with each successive sample year (n = 7 in 2010; n = 9 in 2011; n = 11 in 2012, and n = 135 in 2013). In 2013, 20 fish were marked with Passive Integrated Transponder (PIT) tags and released as part of an angler tag reward program. An additional 15 Northern Pike were tagged during an exploratory gillnetting survey. All other captured fish were killed. During the first four months of the tag reward program, 19 Northern Pike were submitted by anglers; no PIT tagged fish were submitted. The establishment of an invasive predatory fish like Northern Pike in the Columbia River may negatively affect the Rainbow Trout fishery and could threaten the recovery of SARA-listed Columbia River White Sturgeon. A literature review and analysis of habitat data is being undertaken to understand the risk of further spread of Northern Pike in the river, determine potential ecological impacts, and to develop monitoring and mitigation strategies.