Abstract
The study investigates feeding habits of thermophilic species and species with subtropical affinity in the fishing catch in the Bay of Medulin (northeastern Adriatic Sea), and contributes to the knowledge about their presence in recently extended distributional range. In our methodology, the presence of the Seriola dumerili, Sphyraena sphyraena, Lichia amia, Coryphaena hippurus, Caranx crysos, Pomatomus saltatrix, and incidence of Trachinotus ovatus is recorded. A total of 220 specimens are captured during 2017, 2018 and 2019. A dietary assessment is performed, and the index of relative importance IRI was calculated for each prey category. Diet overlap is calculated using Schoener’s index, based on IRI. The principal diet of C. hippurus included Sardina pilchardus and Loligo vulgaris. Pomatomus saltatrix consumed species from the Sparidae family and T. ovatus crustaceans from the Mysidacea family. Different species from genus Atherina are represented important foods for L. amia, S. dumerili and S. sphyraena. Diets of significant importance for L. amia included fishes from the family Sparidae, for S. sphyraena from the Carangidae family, and S. dumerili from the Clupeidae and Muliidae families. Our analysis of diet overlap is based on IRI suggests no diet overlap between analysed fish species from Medulin Bay, and that these species utilise differing trophic niches.
Highlights
The Mediterranean Sea is a marine biodiversity hotspot [1]
Our analysis of diet overlap is based on IRI suggests no diet overlap between analysed fish species from Medulin Bay, and that these species utilise differing trophic niches
It is an ecoregion impacted by severe biodiversity threats [2], mostly because of the ongoing warming trend, due to climate change [3]
Summary
The Mediterranean Sea is a marine biodiversity hotspot [1] It is an ecoregion impacted by severe biodiversity threats [2], mostly because of the ongoing warming trend, due to climate change [3]. Subtropical species are commonly found in warmer eastern and southern parts, Lessepsian migrants in the south, and Atlantic migrants in the west; while boreal species reside in the northern regions [1,7,8]. At the end of the 20th and beginning of the 21st century in the Atlantic, as well as in the Mediterranean, the widening of the range of distribution of thermophilic fish species and species with subtropical affinity has been observed in the northern parts, where they were previously not present or were rarely recorded [9,10,11,12]. The invasion of non-native species will continue to alter local biodiversity records, mainly in its eastern basin, which can spread rapidly northwards and westwards, due to the warming of the Mediterranean Sea [1]
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