Are regional fisheries' catches changing with climate?

- A fishing port in a biogeographic transition zone was chosen for the study.
- Eighty six years of fisheries landings and environmental data were analysed.
- Mean annual SST has increased 0.9 °C from 1926 to 2012.
- Main target species in 2012 the same as in 1927, but landings changed with SST.

Climate change affects ocean conditions, which will in turn impact marine organisms and ecosystems, with consequences for fisheries. The Iberian Peninsula has faced an increase in both air and sea surface temperature, and rainfall has decreased in intensity and frequency in Portugal. As Portugal is the third highest per capita consumer of fish in the world and its coast is located in a biogeographic transition zone, between temperate and subtropical waters, the study of the effects of climate change on Portuguese fisheries is of the utmost importance. The present work focused on Setúbal, an important fishing port in central Portugal. Landings Per Unit of Effort (LPUE) time series (1927-2012) of the most important species were analysed and their relationships with sea surface temperature (SST), rainfall and the winter North Atlantic Oscillation (NAO) index were investigated. Mean annual SST has increased 0.9 °C from 1926 to 2012. The main target species in 2012 were the same as in 1927. However, their landings have changed and have responded to changes in environmental variables, particularly SST. LPUE of the European sardine has shown a decreasing trend and was negatively correlated with SST and NAO, whereas the LPUE of the Atlantic chub mackerel has been increasing since 2000. The LPUE of the common cuttlefish has kept more or less stable through the studied time series, but it was correlated with SST. The LPUE of soles has increased with time and SST. The LPUE of the common octopus was correlated with SST and NAO and has presented higher values since 1975. Further increases in sea temperature in the future will pose challenges for fisheries in Setúbal. Purse-seine fisheries may try to compensate the expected losses in sardine landings by targeting the chub mackerel. Although landings of the most important species in multi-gear fisheries seem to have been favoured by increases in temperature, further studies on the tolerance of each particular species to increases in temperature are needed. As a recent increase in the relative importance of subtropical species in Portuguese fisheries has already been previously detected, climate change may also bring new fishing opportunities for this region.