Updated simple model of the revised stock structure hypothesis for South African sardine

Nine alternative models to test the revised stock structure hypothesis for South African sardine are considered. These are an extension of work presented by de Moor (2022a,b) in December 2022 to test, in particular, key revisions to the hypothesis arising from the May 2023 Small Pelagic Scientific Working Group meeting. The models exclude any commercial catch for these initial testing purposes. This hypothesis assumes Cool Temperate Sardine (CTS) are found off the west coast only, with some CTS moving at age 1 to the east coast (outside the modelled area). Warm Temperate Sardine (WTS) are found off the west and south coasts, with passive transport of some WTS spawning products from the south coast to the west coast and active movement of WTS from the west coast back to their preferred habitat on the south coast. Growth is now modelled to be coast‐dependent and recruitment of WTS and CTS on the west coast are now estimated separately.