Climate-related geographic shift and sudden population increase of a small pelagic fish (Sardinella aurita) in the eastern Mediterranean Sea

Abstract

Round sardinella (Sardinella aurita) is a thermophilous small pelagic clupeid fish that is exploited by the purse-seine fishery across the Mediterranean Sea. For many years, its Aegean Sea distribution has been confined to the southern part of the sea because of its preference for warmer waters. Recently, the geographic distribution of round sardinella, as reflected in purse-seine catches, has gradually shifted, expanding towards the north. The northward expansion is directly related to the sea warming observed in the northern Aegean Sea. Besides its distribution extension, the population of round sardinella in the northern Aegean Sea exhibited a 30-fold increase since the early 1990s and showed a positive correlation to sea surface temperature. Distributional changes and population outbursts may have detrimental ecological effects to the community and ecosystem but may also affect the local fisheries economics by altering the composition and amounts of catches.