Research Document 1998/89

Survey of the Northern abalone, (Haliotis kamschatkana), in the central coast of British Columbia, May 1997

By A. Campbell, I. Winther, B. Adkins, D. Brouwer, and D. Miller

Abstract

Northern or "Pinto" Abalone, Haliotis kamtschatkana, fisheries in British Columbia (B.C.) have been closed since 1990 due to conservation concerns. Surveys by DFO (Fisheries and Oceans Canada) at indicator sites, during 1979-97, indicated a continued decline of abalone densities on the central coast of B.C. Total abalone density declined 43.75 % between the 1993 and 1997 survey. The percentage of index sites in which no "legal" abalone were found almost doubled to 62.5 % in 1997 from 33.3 % in 1993. Comparison between areas, surveyed during 1997, indicated higher total exposed abalone densities in the south, such as the Simonds Group and near Stryker Island, than for other north areas. The density estimates from this study were similar to those from an independent transect survey conducted by the Heiltsuk First Nations in the Simonds Group and near Stryker Island during May, 1997, after the data were standardized to similar depth ranges. However, abalone densities in these southern areas of the central coast of B.C. were still well below those reported by Breen and Adkins (1982) in a few samples during 1980, and were at density levels similar to those at index sites when the fishery was closed. The mean size of a sample of over 6000 illegally harvested abalone, found in Calamity Bay during 1997, was larger than that found in any of the abalone populations surveyed in this study. This indicated that poachers had selectively harvested mostly large mature abalone, but with no regard for the legal size limit since 16.6 % of the illegally harvest abalone were < 100 mm SL. Illegal harvesting not only further depletes already depressed abalone stocks, but also reduces their reproductive potential, by removal of large mature abalone, and hinders attempts to rehabilitate abalone populations in B.C. through fishery closure.

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