engleski

Spatial and temporal patterns of settlement among juvenile inshore fishes of Eastern Adriatic Sea, Croatia

The spatial and temporal patterns in settlement of the juveniles of around 30 littoral species along the Croatian part of Adriatic Sea were studied from May 1998 to the present days. Sparidae was the most abundant family comprising 61, 47% (13 species), followed by Labridae (10, 37%, 11 species) and Atherinidae (9, 35%, two species). The most abundant juvenile taxa were the sparid Boops boops and the atherinid Atherina boyeri accounting together for 76, 91% of the total catch. Settlement intensity varied spatially, temporally and among species. Sparid species recruit at different times of the year, whereas labrids recruit during summer months, from July to September. Most of the juveniles studied settle to well defined habitats with characteristically distinctive substrate types. Depth was one of the main factors regulating the distribution of settlers. Sparid species recruit primarily in the shallowest zone (0 to 3 m), and most of them prefer varied bottoms (sand, gravel or rocky ; vegetated or unvegetated). Labrid species show a high degree of seasonal and spatial co-occurrence, and are normally found on rocky substrates with high algal cover, while atherinids show no clear link with the type of substrates. Some species with similar habitat requirements show a clear seasonal segregation, with each species occupying successively the same zones at a different time of the year. Observed temporal staggering of recruitment was probably a mechanism for reducing possible interspecific competition. Settlement intensity to nearshore habitats exhibited high year-to-year variations at both local and regional scales. The implications of this study are important not only for better understanding the patterns of recruitment dynamics in various juvenile inshore populations, but also in terms of management of these resources in the Adriatic Sea.

spatial; temporal; settlement; juvenile fish; Croatia

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