Initial results from fitting the revised sardine two-mixing-stock model to data from 1984-2014, including consideration of parasite prevalence-by-length sampled from November surveys 2010-2014

The operating model for the South African sardine resource is being updated from the last assessment (de Moor and Butterworth 2015a) to take account of data collected between 2012 and 2014. Both a single and two-mixing-stock hypothesis will be considered again, although revisions to the two-mixing-stock hypothesis are also being considered. New data on the differences in infection of sardine on the west and south coasts by a digenean ‘tetracotyle-type’ metacercarian endoparasite are to be included in the model with the aim of obtaining improved estimates of sardine movement for the two stock hypothesis.

This document presents some initial results from the revised two mixing stock hypothesis only.