PRELIMINARY STUDY ON THE EFFECT OF HABITAT CONDITIONS ON REPRODUCTION OF SMALL PELAGIC FISH IN THE MIDDLE ADRIATIC SEA

Abstract

The aims of this study were to describe the reproductive cycle of the small pelagic fish in the Central Adriatic (GSA 17) determining wheter intra- and inter-annual reproductive trait variations, if any, are influenced by environmental flactors. Biological data were collected from mid-water pelagic trawl commercial catches landed in Ancona in 3 yers over 21-year period (2001, 2011, 2022). Environmental data, i.e. Sea Surface Temperature and Chlorophyll a, were obtained from Copernicus Marine Environment Monitoring Service. Results showed that anchovy and sardine spawning intensity, denoted by gonadosomatic index, did not show any inter-annual changes. A strong  correlation between decrease in temperature and sardine gonadal development seems to confirm the preference of this species for cold waters to spawn. The relationship between gonadosomatic index and chlorophyll a is, therefore, probably a reproductive strategy to ensure food availability to juvenile stages in sardines. These are the outcomes of a preliminary study; further analysis on a longer time series will help to deepen the effects of habitat conditions on reproduction of small pelagic fish in the Adriatic Sea.