Available data for determining the occurrence and distribution of Cool Temperate and Warm Temperate Sardine components by life history stage

A recent genomic analysis of South African sardine Sardinops sagax resulted in a revised hypothesis of the stock structure of this population that was presented and discussed at the 2022 DFFE/MARAM International Fisheries Stock Assessment Workshop. The Workshop Panel considered that understanding of the stock hypothesis was limited, specifically regarding the spatiotemporal distribution of different life history stages of Cool and Warm Temperate Sardines (CTS and WTS) and how available data related to assessment model components. Observational data and model results on eggs (and larvae), pre-recruits, recruits, and adults of South African sardine are compiled from fisheries-dependent and fisheries independent sources and include surveys of ichthyoplankton, pre-recruits, recruits and adults; biological characteristics such as length frequency distributions, gonadosomatic indices, otolith characteristics, genomics and parasite biotag prevalence-at-length; and results from coupled 3D hydrodynamic-individual based models. These data are then used to infer seasonal and spatial patterns in spawning, passive and active movement, recruitment, and distribution of CTS and WTS for informing the model of the sardine population.