The updated assessment model for the revised sardine stock structure hypothesis

This document details the stock assessment model of the revised South African sardine stock structure hypothesis. The model allows for two stocks (Warm Temperate Sardine and Cool Temperate Sardine), distributed between two areas (the west and south coasts of South Africa, separated at Cape Agulhas). Sardine growth is coast‐dependent, and the distribution of length‐at‐age off the south coast is modified from the south coast growth curve to accommodate the immigration of individuals from the west coast which have grown according to a different growth curve for the first part of their life on the west coast. Catch by stock off the west coast can either be proportional to the numbers of exploitable sardine‐at‐age by stock off the west coast, or related to alternative pre‐specified weightings of CTS to WTS between the region to the north of Cape Point and that between Cape Point and Cape Agulhas.