Stock assessment, ecology and economics as criteria for choosing between trap and trawl fisheries for spiny lobster Palinurus delagoae

Biological information collected during a 4-year experimental trap-fishery for Palinurus delagoae off South Africa was used to estimate growth rates, size at sexual maturity, and natural mortality. These parameters, together with an estimate of total mortality and catch-at-length information from the trap-fishery and a crustacean trawl fishery in the same region, were used in a deterministic length-based cohort analysis to estimate fishing mortality and recruitment, and to assess the impact of the two fisheries on the resource. The impact of both trap and trawl fisheries is greatest on immature and small mature lobsters (60 mm