engleski

Distribution and community structure of juvenile fish populations in the inner shallow areas of Medulin Bay

In the southernmost part of Istria, next to Rt Kamenjak, there is a protected area of Medulin Bay that belongs to the Natura 2000 network (HR3000173). The inner part of bay is a shallow coastal area with several closed bays rich in fresh water sources. In the most indented part, Pomer Bay (HR3000174) stands out as a highly productive area where any form of fishing is prohibited by a special regulation. In order to obtain data on the composition, abundance, biomass and structure of fish communities, sampling of juvenile fish was carried out at four locations (Šćuza, Bijeca, Vižula, Tašalera) in September 2021 using the small coastal trawl net (length 50 cm, height 30-250 cm, mesh size in the central part 4 mm). In order to make the sampling as representative as possible, 3 replicas were carried out at each location. 30 species from 15 families were recorded, and a total of 2, 223 individuals, with a total weight of 5, 266.81 g, were caught. As expected, Šćuza Bay stands out for the largest number of individuals (1, 222 individuals) and the highest biomass (2, 973.08 g). In relation to the biodiversity, the Vižula site stood out with the highest number of species (20 species from 12 families). This site is characterized by more diverse habitat features which supports a greater abundance and variety of species. The structure of fish communities was characterized by the predominance of a small number of species in total number and biomass. The most numerous species at all locations was big- scale sand smelt (Atherina boyeri) (55.33%), which shows that its occurrence is not conditioned by the type and peculiarities of the habitat. The obtained results undoubtedly indicate the exceptional importance of the studied bays as nursery areas of juvenile fish before moving to deeper waters and joining adult populations.

Natura 2000, Pomer Bay, nursery areas, habitat differences

nije evidentirano