Research Document - 2004/117

Northern Abalone Case Study for the Determination of SARA Critical Habitat

By Jamieson, G.S., E.J. Gregr, C. Robinson

Abstract

This evaluation of critical habitat (SARA context) is one of a series of seven national case studies to investigate what critical habitat means for aquatic and marine species. It looks at this question for northern abalone (Haliotis kamtschatkana) in British Columbia, a cryptic, broadcast spawning, benthic gastropod of limited mobility that has been listed as "threatened" by COSEWIC. Little is know about this species’ larval planktonic dispersal or coastal adult spatial distribution. However, populations are widespread and contagious in distribution, and recruitment has been declining for the past two decades. Over-harvesting during the fishery, which was terminated in 1990, and subsequent poaching are believed to have contributed to the recent low recruitment. To determine critical habitat for abalone, the following steps were adopted: 1) estimate total potential habitat suitable for northern abalone over selected areas of the BC coast; 2) model potential abalone larval dispersal to determine dispersal characteristics and the likely scale of source and sink populations, and 3) identify subsequent studies to evaluate predictions made, and to refine the critical habitat assessment procedure for abalone developed and proposed here. Predictions of suitable abalone habitat for the west coast of Vancouver Island and Haida Gwaii (Queen Charlotte Islands) were produced, and larval dispersal modeling was conducted within the Broken Islands in Barkley Sound. This latter portion of the study suggested that specific spatial areas may have larger, more consistent abalone recruitment than others. Suggestions as to how to identify critical abalone habitat are made, given the data that are currently available.

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