Climate change alters the temporal persistence of coastal-pelagic fishes off eastern Australia

Abstract

Abstract The climate-driven redistribution of fisheries species is altering their availability to fishers, necessitating projections of species redistributions that directly relate to future fishing opportunities. We propose that a valuable proxy for fishing opportunity is the proportion of the year that target species are available to fishers, which can be approximated by the temporal persistence of suitable habitat in defined regions. Here, we quantify changes in temporal habitat persistence (months/year) within five eastern Australian bioregions over the period 2010–2060 for four coastal-pelagic fishes: bonito (Sarda australis), spotted mackerel (Scomberomorus munroi), Spanish mackerel (Scomberomorus commerson) and dolphinfish (Coryphaena hippurus). When species were analysed collectively, a significant reduction in the temporal persistence of suitable environmental habitats was evident in the most equatorward (i.e. Tweed-Moreton) bioregion, while significant positive increases were found for poleward bioregions (e.g. Batemans and Twofold Shelf bioregions). The greatest increases in temporal habitat persistence were projected for bonito in the Batemans Shelf bioregion and Spanish mackerel in the Hawkesbury Shelf bioregion (+2.2 and + 1.5 months/year between 10-year averages centered on 2020 and 2050, respectively). By demonstrating temporal habitat persistence as a measure of fishing opportunity, we highlight the potential for this metric to be an effective means of communicating to fishing stakeholders the need to adapt to climate change.