Evaluating control of green crab at pipestem inlet

Abstract

The invasive European green crab, Carcinus maenas, has been present on the west coast of Vancouver Island since 1998. Annual trapping has been conducted since 2010 at Pipestem Inlet to determine if depletion is a potential mechanism to eradicate or control established populations. Although catch per unit effort decreased during annual trapping events, suggesting depletion efforts may be reducing this localized population, this trend was not apparent between years. For example, there was a drastic increase in population size from 2010 to 2012, and since then population size has only gradually declined, despite annual depletion efforts. However, average carapace width declined during each trapping event and between years, and 2010, 2012 and 2013 catch rates showed a female bias, suggesting depletion efforts have affected population structure. Overall these intensive trappings events have significantly altered population demographics at Pipestem Inlet, but effects on population size are less apparent, especially over time.