engleski

Long-term catch variations of the shallow-water fish assemblage in the southern Adriatic Sea, Croatia

Pluriannual investigation of the distribution and abundance of a shallow-water fish assemblage was conducted during 1998– 2006 in several sites along the south Adriatic Sea shoreline. Sampling was carried out using a 25 m long beach seine, on a monthly basis ; the sampling locations were designed to cover different habitats (seagrass meadows, sand only areas, sandy areas with rock outcrops, rock areas, mudd areas). Altogether 94 species belonging to 37 families were caught. In collected samples dominant families were Sparidae (33.48%), Mugilidae (28.91%) and Labridae (7.22%). From 17 commercially interesting species, Atherina hepsetus represented 13.94% of all catches, Pagellus acarne 13.40%, Boops boops 7.26%, and Diplodus vulgaris 3.98%. From other, commercially less interesting species, most common were Coris julis, with 4.45%, Symphodus ocellatus 2.42% and Symphodus roissali 1.04%. The remaining species contributed less than 0, 3% of the catch. The species assemblage at sampling sites were similar and showed much overlap of dominant species. There was seasonal fluctuation in assemblages indices: generally, the number of captured species and individuals increased in spring and summer and decreased in late autumn, but abundance of dominant species varied among years. Pluriannual patterns in distribution and abundance of various fish species are probably related to timing of spawning and recruitment, as well on hydrological and geomorphological features of sampling area. Demographic analysis structure revealed the fact that almost over 95% of sampled fish were juveniles or subadults. These results showed that nearshore shallow areas (0-4 m) serves as nursery and feeding grounds for juveniles of variety fish species. So, it is therefore necessary to protect natural habitats where juvenile fish live, since it is certain that the wealth of sea and maintenance of fish population will largely depend on it, especially in regions with strong anthropogenic pressure.

long-term catch variations; shallow-water fish assemblage; Croatian southern Adriatic Sea

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