Balancing production and sustainability in multi-species fisheries with technical interactions is challenging as the optimal harvest of one species rarely optimises the catches of the other species caught with it. This is particularly challenging for rebuilding species where target species catches must be set so they do not impact rebuilding stocks beyond levels that still allow recovery. This problem exists in the Southern and Eastern Scalefish and Shark Fishery (SESSF). This fishery catches over two hundred species, with more than 80% of the economic value derived from 10 target species, and with six species currently classified as recovering.
We used multi-variate statistics to classify clusters of fishing operations with similar catch composition. Aggregating these clusters into métiers identified the technical interactions between target and rebuilding species. We calculated the ratio of target species to rebuilding species catch in each métier then estimated the unavoidable bycatch of SESSF rebuilding species under different scenarios of future target species catch. This research has been used by managers to inform setting of SESSF catch limits since 2020. We outline the approach applied and discuss current and future challenges to facilitate the sustainable management of multi-species fisheries.