Research Document - 2001/141

Quota options for the Red Sea Urchin fishery in BC for fishing season 2002/2003

By A. Campbell, D. Tzotzos, W.C. Hajas, L.L. Barton

Abstract

Annual landings of red sea urchin (Strongylocentrotus franciscanus) increased rapidly in the early 1980s for the south coast of British Columbia (B.C.) and in the late 1980s for the north coast, but subsequently were reduced and stabilised by quotas. Coastwide landings were 4,815.4 t valued at approximately $ 8.4 M (Cdn.), with 110 licenses issued during the 2000/2001 fishing season. Bed areas were obtained by digitising locations on charts indicated in harvest logbooks during 1997-2000. Analyses of surveys, during 1994-2001, provided estimates of mean density and weights of red sea urchin biomass within beds. Natural mortality rates of red sea urchins were assumed, for fishery management purposes, to be between 0.075 and 0.15. The minimum size limit was reduced from 100 mm to 90 mm test diameter (TD) for the 2000-2001 fishing season. Of the total (N = 22,739) measured in a survey of red sea urchins in processing plants, harvested throughout the 2000-2001 fishing season, the majority (95.0 %) was in the 95-140 mm TD size group and only a few (4.3 %) were < 95 mm TD. Biomass and quota options were estimated for a variety of size limits (e.g., > 90, > 95, > 100, 95-140 mm TD) for red sea urchins in B.C. Further surveys for red sea urchin density are required in areas of B.C. where surveys are > 5 years old, and that have been heavily fished and or invaded by sea otters. Reliable biomass estimates and accurate estimates of bed areas, natural mortality and recruitment rates for red sea urchins in most areas of B.C. are required to manage this fishery effectively.

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