Changes in the spawning habitat of two small pelagic fish in the Northwestern Mediterranean

13 pages, 3 figures, 3 tables, supporting Information https://dx.doi.org/10.1111/fog.12464

We investigated the effects of three sea surface oceanographic variables (temperature, salinity and chlorophyll a) on the abundance of eggs and larvae of two summer-spawning species in the NW Mediterranean sea, the anchovy Engraulis encrasicolus and the round sardinella Sardinella aurita, based on data from ichthyoplankton surveys carried out in the 1980s, 2000s and 2010s. The environmental data showed an increase in sea water temperature and salinity along time, coupled with a decrease in chlorophyll a (proxy for primary production). These long-term directional changes in environmental conditions helped explain the important reduction observed in the abundance of eggs and larvae of anchovy, as well as shrinking of spawning habitat in this species. At the same time, the probability of occurrence of round sardinella has increased from practically zero in the 1980s to probabilities near 1 along the coastal area of the study region in the two decades of the 21st century. Given that the trends observed in the environmental variables along the three decades of study are expected to continue during the 21st century, as a consequence of climate change, the spawning habitat of anchovy is expected to continue decreasing, while round sardinella habitat can expand. Considering that anchovy is of high commercial importance in NW Mediterranean fisheries, while round sardinella has very low commercial interest, our results show that the viability of small pelagic fisheries in the area may be compromised

This research is partially supported by the CERES project (H2020, EU 678193) and by the Spanish Ministry of Economy and Competitiveness (CTM2010-18874 and CTM2015-68543-R)

With the funding support of the ‘Severo Ochoa Centre of Excellence’ accreditation (CEX2019-000928-S), of the Spanish Research Agency (AEI)

Peer reviewed