Abstract
Marine capture fisheries play crucial roles in global aquatic protein supply and livelihoods of millions of people. Anthropogenic climate change comes as an overlying threat, potentially necessitating substantial adjustments of harvest control rules or rebuilding plans, especially for species (stocks) that are naturally adapted to restricted environmental fluctuations. Stock productivity, defined as surplus production provided by per unit of stock biomass, offers an informative yet underutilized metric for assessing these impacts. With the help of global fishery‐related databases and earth system models, stock productivity estimates were related to key biophysical drivers by state‐of‐the‐art statistical methods. The ultimate goal thereby is to clarify how climate change has affected and will continue to affect this harvest potential. Results show that the hindcasted global stock productivity (710 stocks) exhibited pronounced stock‐specific and regional heterogeneity, with signs of an overall decline (1980–2022). Variations in sea temperature and chlorophyll concentration significantly affected the productivity of about half of the assessed stocks (1993–2020). The subsequent productivity projections indicated relatively moderate reductions in the global mean productivity proxy (2021–2100), though these projections were characterized by uncertainty and with different data availability depending on the regions. However, the important finding of a general balanced prevalence of stock ‘winners’ and ‘losers’ lessened this regional quantification problem. As inferred, by the end of the century, global productivity (also applied to fishery landings) is projected to decline by 3.0% (−6.3% to +0.4%) under a ‘business‐as‐usual’ scenario and 1.0% (−1.6% to −0.3%) under a ‘sustainability’ scenario. Thus, our research indicates relatively moderate effects of climate change on the global fisheries productivity, though with the above‐mentioned existence of clear winners and losers. This finding contrasts with previous investigations that depict remarkable declines in future fishery landings.