Influence of environmental factors on different life stages of European anchovy (Engraulis encrasicolus) and European sardine (Sardina pilchardus) from the Mediterranean Sea: A literature review

Abstract European anchovy (Engraulis encrasicolus) and sardine (Sardina pilchardus) are two of the most important small pelagic fish species in terms of biomass and commercial interest in the Mediterranean Sea. Their populations are clearly influenced by environmental variations, making them good bio-indicators of climate-driven changes. Here, we reviewed the different environmental factors documented to affect anchovy and sardine biology by using a systematic review approach on methodologies used to study environmental effects on these species, variables identified to play a role, and relationships found between ecological variables and the environment. Our results show that available studies were heterogeneously distributed, being more abundant for anchovy adults in the Western Mediterranean. Among all the environmental factors found significant, temperature, depth, salinity and chlorophyll-a concentration were the most studied for both species. Further emphasis was placed on the effect of these four variables, with various relationships found for the different life stages and areas. This review provides a general insight of what is known about how the environment influences growth, spawning, abundance and distribution of anchovy and sardine in the Mediterranean Sea, and identifies gaps of knowledge for future research. Our study sets a knowledge baseline for future studies about climate variability and change in the Mediterranean basin.