CERES researchers 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.
Maynou F, Sabatés A, Raya V. Changes in the spawning habitat of two small pelagic fish in the Northwestern Mediterranean. Fisheries Oceanography. 2020.