engleski

Contribution to the ecology of the sponge Suberites domuncula (Olivi, 1792): A field study (northen Adriatic Sea, Croatia)

Background and purpose: Through centuries sponges and other marine invertebrates have been widely affected by their use in commercial trade and for human benefit, including usage for public aquaria and in scientific work. Sponge populations are also impacted by bottom fishing and by pollution. Due to the limited knowledge about the extent of these factors the main objective of this study was to estimate the population abundance and colour variations of the sponge species Suberites domuncula near Rovinj (northern Adriatic Sea, Croatia). Materials and methods: Specimens of S. domuncula were studied in situ and collected by SCUBA diving at a site about 2.7 km off Rovinj along a 3 x 50 m transect (32.8-33.5 m depth). Results and conclusions: During a 16 month period from June 2004 to September 2005, 768 specimens in total have been recorded. We determined for the first time abundance of S. domuncula as one individual per 2.8± ; ; 0.9 m2. During the research period we observed sponges of different colours: red-orange, blue, yellow, brown, and white as well as combinations thereof with differing patterns. There is a great prevalence of the red-orange colour variety of 85.2± ; ; 4.4%. S. domuncula, with an abundance of 34 to 96 specimens for 150 m2 at investigated site does not appear as a threatened species, moreover, according to the data given by Zavodnik and Šimunović (28), it appears more common in Rovinj area than in the rest of the northern Adriatic.

Suberites domuncula ; field study ; abundance ; colour varieties ; northern Adriatic Sea

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