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Temporal trends in abundance, biomass, diversity and structure of eastern middle Adriatic coastal fish assemblages

Coastal waters are highly structured and valuable marine ecosystems recognized as pro- ductive areas used by several fish species for reproductive activities, foraging and shelter. Many of valuable coastal habitats are under increasing environmental and human pres-sures. In last decades, climate change and fisheries have driven significant changes in ichthyocommunities in term of distribution, abundance and biomass. The aim of the study is to investigate temporal changes in the composition and structure of littoral juvenile fish assemblages through their response to environmental and anthropogenic factor. Samples were collected on monthly basis in 1991 and from March, 2017 to February 2018 on seasonal basis in area of cove Sovlja near Šibenik. The individuals were caught using a special constructed small shore seine (L = 25 m ; minimum mesh size 4mm) same con-struction and technical features that used in sampling before. A total of 17216 fish weigh-ing 19.399 kg, comprising 25 families and 70 species were recorded in 1991 and a total of 9887 fish weighing 11.260 kg, comprising 20 families and 55 species were recorded in 2018. The Sparidae and Gobiidae were the most important families in 2000 and 2018. During the whole study the most abundant and frequently observed species were the big-scale sand smelt, Atherina boyeri, which was present with 52% of total catch and 69.4 % of shore seine sampling (2018) and the Mediterranean sand smelt, Atherina hepsetus, which was present with 26% of total catch and 50 % of shore seine sampling (1991). These results clearly indicate that the littoral fish assemblages in cove Sovlja changed continuously during the study period. Multivariate community analysis of these data may shed light on temporal changes of fish species through response to human-induced factors such as fisheries and habitat modification due climate changes.

Temporal trends, abundance, biomass, diversity, structure, Adriatic coastal fish assemblages

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