Age-Structured Stock Assessment Modelling of Major Finfish Species

Age structured models use information on the changes in the age composition of a stock, in conjunction with the catch and effort information to provide estimates of the changes in their abundance due to fishing. These types of models are often used for finfish species because they have otoliths or other hard structures from the age of individuals can be determined. Such models require a time series of catch and effort data plus a number of years where the age composition of the population has been estimated. Estimates of the growth, natural mortality and either direct estimates of relative recruitment strength or a stock recruitment relationship are also needed to generate the model.Models have been successfully generated for a number of finfish species in WA (including a number of stocks of pink snapper in the Shark Bay region, Red Emperor, Goldband snapper, Rankin cod in both the Kimberley and Pilbara regions, pilchards off the south coast), which are now used in the management of fisheries. These models will be updated at regular intervals to coincide with major reviews of these fisheries. Similar models are in the process of being generated for all the main finfish species within each bioregion.Time : ongoing.