Problems in estimating population length at age from commercial catches, the Patagonian toothfish as an example

Age based fishery population models require information on size at age of the fished population and the commercial catch. Age-length keys can be produced by standardised random sampling of the commercial catches. This information does not necessarily reflect the size at age of the fished population and may be seriously biased. Through the use of a model, and using the Patagonian toothfish as an example, a method is developed to estimate size at age of the population using information collected from the commercial fishery.