engleski

Recent occurrence of <i>Pyrosoma Atlanticum</i> (Thaliacea, Pyrosomatida) in the South Adriatic

Gamulin (1979), during his investigations of thaliacean abundance and distribution in the Adriatic Sea in the period from 1947 to 1952, found only larvae of <i>Pyrosoma atlanticum</i>, most commonly in the tetrazooid form, and in the greatest abundance near the Vis island. Nevertheless, he states that <i>Pyrosoma atlanticum</i> is common in the South Adriatic were it is occasionally caught by the fishermen in the fishing nets. For the period 1974-1975 Katavić (1976) states that he found 7 tetrazooids and 3 small adult colonies in the South Adriatic. In the period from 2007 to 2020 only few tetrazooid colonies were caught by zooplankton nets and adult colonies were never observed on the surface. In 2021, during zooplankton sampling trip in the open South Adriatic on 9th and 10th of September, we observed 13 adult colonies of <i>P. atlanticum</i>. Three of them were caught by hand nets and their identity was confirmed by inspection under the binocular. At the time of collection the surface salinity was extremely high (39.3) and surface temperature was 25.4°C. It seems that <i>P. atlanticum</i> is not as common in the Adriatic now as it was in the past. It occurrence seems to vary and it is possible that it is governed by circulation changes in the Ionian Sea, most notably BiOS (Bimodal Ocillating System). Due to the termophilic nature of <i>P. atlanticum</i> and on-going climate changes it is possible that <i>P. atlanticum</i> will become more common in the Adriatic Sea than it was in last decades.

Pyrosoma atlanticum ; climate change ; Thaliacea ; Adriatic Sea

nije evidentirano