The effects of climate change on cross-boundary larval flows in global marine fisheries

Abstract:

Flows of fish spawn across international boundaries form a significant contribution to eventual fishery catch. Climate change may disrupt these flows in the future through multiple channels: changing spawning suitability, shifting cross-boundary currents, accelerated larval development, and changes in settlement likelihood. These biophysical impacts, in turn, can result in reduced national stocks, leading to unintentional mismanagement if changes in cross-boundary flows are unaccounted for. We evaluate each of these climate impacts, and relate them to socioeconomic outcomes of interest to local communities. To do so, we combine a Lagrangian modelling scheme to study the dispersal of spawn with extensive fisheries data covering over 2000 commercially fished species. We model changes in suitability based on envelopes that account for sea temperatures, primary productivity, and sea-ice. Temperature-dependent larval development, floating duration, and adult movement are modeled using newly-developed empirical relationships. Changes in fecundity and life-stage suitability driven by climate change are drawn from the literature. We analyse the contribution of each of these effects globally on forecasted catch, economic value, and local labour outcomes.