Preliminary aspects of a simulation model to be used for evaluating the experimental crab fishery

At the 1993 meeting of the Working Group on Fish Stock Assessment, members requested that work be undertaken to evaluate certain aspects of the experimental management strategy for the Antarctic crab fishery. A simulation model is proposed for conducting this work. Length frequency and catch rate data from the 1991/92 crab fishery are used to motivate the construction of an ontogenetic migration model for describing crab distribution, movement, and recruitment during the simulation. The fishery simulation is spatially explicit, and the dynamics of crab abundance are described on a daily basis. The simulation includes advective and diffusive movement rates, a lagged Beverton-Holt stock recruitment relationship, and a model for catch that contains a random normal deviate. Finally, an algorithm is developed for describing the spatial and temporal distribution of fishing effort during the simulation. This algorithm is based on the idea that each fishing vessel constructs a map of expected catch rates across the fishing grounds. Each vessel updates this expectation map on a daily basis and uses it to determine the distribution of targeted fishing effort and searching effort.