Results from the stock assessment model of the revised South African sardine stock structure hypothesis

Results from the model for the revised stock structure hypothesis for South African sardine are shown. Conflicts between data – particularly in the model’s ability to fit the hydroacoustic survey estimates of November biomass off the South Coast in recent years – are demonstrated through alternative weighting of length frequency data. It is also shown that an additional constraint on the growth curves is required to ensure faster growth in the first few months of life off the south coast compared to the west coast which is expected a priori. Initial results are also shown for additionally fitting the model to parasite prevalence-at-length data, although this hypothesis likely requires further modification before acceptance.