Comparative population size estimates for a portion of the red crab Geryon maritae stock off the South West African coast

Abstract

The size and the density of the red-crab population between latitudes 19°20′ and 20°10′S and depths 400 and 900 m are estimated by a tag-recapture technique. Results are compared with estimates of stock density in the same area by three other methods (trawling, photography and effective fishing area [EFA]). Tagging and photography yielded similar estimates of crab population size (21,6 and 19,5 million crabs respectively) whereas trawling (1,9 million) and EFA techniques (81,4 million) apparently under- and overestimated stock size respectively. Fishing mortality (based on the ratio of crabs returned to those tagged) is estimated as 0,24 for males and 0,41 for females. © 1988 Taylor & Francis Group, LLC.