engleski

Nursery role of transitional waters for juvenile fish species along the eastern Adriatic coast

The importance of transitional water ecosystems as nursery habitats and feeding grounds for juvenile fish species is well-known. However, detailed studies of colonization patterns of juvenile fish in specific ecosystem types are still missing. One hundred taxa ranging across more than 30 families (both marine and freshwater) were collected. Each taxon is characterized by trophic category, spawning area, ecological requests and determined as potential indicator/ new/ or alien species. The modified Estuarine Fish Index (M-EFI), which each aim to assess a different functional aspect of the estuarine fish assemblages and the integrated quality of the ecosystem (general degradation) was used. Also, assessment of anthropogenic pressure on coastal zone by calculating the LUSI index using the publicly available data was done. Pooling all species together, the structural features of the assemblages, relative abundance of families, and abundance of individual species all showed significant temporal patterns. Temporal segregation of species belonging to the same family or genus was obtained, suggesting that they avoid competition for space and resources by timing inward migration and peak occurrence differently. Of the environmental driving forces, salinity was the main factor affecting the distribution of individuals and species. The catch of a number of juvenile marine species confirmed the role of transitional waters as a nursery and feeding areas. With higher eutrophication, the transitional waters are more productive allowing more food both for resident and juvenile marine fishes. Also, productive waters offer more complex habitat providing micro niches and shelters for juveniles. The land impact, as sum of urban, agricultural and industrial pressures, is still low enough to encourage good ecological status. Low m-EFI values, obtained for low LUSI values is rather reflection of existing hydrographic and meteorological situation and seasonal variations than indicator of profound ecological changes in the transitional waters.

nursery habitats, fish, transitional waters, Adriatic Sea

nije evidentirano