Novi dizajn istraživačkih mreža stajačicama za uzorkovanje riba u Jadranskom moru

Three types of multi-mesh benthic survey gillnets were tested for their performance in the uniform muddy bottom habitat of the Bay of Piran. We describe the compared methods, present their positive and negative aspects and suggest a sampling design that could be used with different research goals. The research sampling was performed in winter in the years from 2010 to 2012. The sampling site is situated close to a sea bass rearing fish farm in the Northern Adriatic Sea. With the Nordic 1.5 type nets 5 species were detected compared to the 23 and 20 species detected with the Adriatic 2.5 and 5.0 nets. In the Nordic 1.5 type nets only demersal species were caught and even for those a much greater sampling effort would be required to reach a representative sample. On the other hand, both the Adriatic type nets also caught benthopelagic and pelagic species, and a correlation between net height and size of fish in these two nets was detected. While both the Adriatic type nets proved successful in achieving a representative sample of fish assemblage, the Adriatic 2.5 nets performed better in terms of CPUE and as such also reached a better cost-benefit ratio.Tri vrste jednostrukih mreža stajačica različitih veličina oka su testirane na uniformnom muljevitom dnu Piranskog zaljeva. U radu su opisane i uspoređene metode, predstavljeni njihovi pozitivni i negativni aspekti te predložen plan uzorkovanja koji bi se mogao koristiti za različite istraživačke ciljeve. Istraživačko uzorkovanje se odvijalo zimi u razdoblju od 2010. do 2012. godine, a uzorkovalo se u neposrednoj blizini uzgajališta lubina u sjevernom dijelu Jadranskog mora. U Nordijskom 1.5 tipu mreža nađeno je 5 vrsta organizama, u odnosu na 23 u Jadranskom 2.5, te 20 vrsta nađenih u Jadranskom 5.0 tipu mreže. Nadalje, u Nordijskom 1.5 tipu mreže su uhvaćene samo pridnene vrste organizama, s tim da je do reprezentativnog uzorka bilo puno teže doći. S druge strane, u oba Jadranska tipa mreža su nađene bentopelagične i pelagične vrste riba, te je utvrđena korelacija između visine mreže i veličine riba. Premda se s obje vrste mreža Jadranskog tipa relativno lako došlo do reprezentativnog uzorka, Jadranska 2.5 mreža je dala bolje rezultate s obzirom na CPUE te tako postigla bolji omjer uloženog i dobivenog

Multi-annual investigation of the spatial distributions of juvenile and adult sole (Solea solea L.) in the Adriatic Sea (northern Mediterranean)

15siThe common sole (Solea solea) is one of the most important demersal resources in the northern and central Adriatic Sea (GFCM GSA 17). Landings from this basin make up around 23% of the overall Mediterranean and Black Sea production. Despite the economic relevance of sole in the Adriatic Sea, and its inherent property of being shared among three countries (i.e. Italy, Slovenia and Croatia), studies on its spatial distribution are scarce and aged. Therefore, the aim of the present study was to assess the spatial distribution and investigate the dynamics of this species in the GSA 17. Samples of common sole were collected in the framework of yearly rapido trawl surveys (SoleMon), during late autumn, from 2005 to 2010, i.e. the spawning season of common sole in the Adriatic. Results highlighted that juveniles are mostly concentrated in shallow water (0–30 m depth) along the Italian coast and their spatial distribution persisted along the sampled years. By contrast adults were mainly distributed in the central/eastern part of the basin at depths >30 m. As a result of the different spatial distributions, juveniles are exploited exclusively by Italian vessels, especially by beam trawlers (i.e. rapido trawl), while adults are caught by Croatian and Slovenian fishing fleets in their respective national waters and by the Italian fleet operating in international waters. These results, while shedding light on the common sole spatial ecology in the Adriatic, represent crucial information for the setting of international collaboration for a rational spatial-based management of the resource.noneopenGrati, Fabio; Scarcella, Giuseppe; Polidori, Piero; Domenichetti, Filippo; Bolognini, Luca; Gramolini, Roberto; Vasapollo, Claudio; Giovanardi, Otello; Raicevich, Saša; Celić, Igor; Vrgoč, Nedo; Isajlovic, Igor; Jenič, Aljaž; Marčeta, Bojan; Fabi, GiannaGrati, Fabio; Scarcella, Giuseppe; Polidori, Piero; Domenichetti, Filippo; Bolognini, Luca; Gramolini, Roberto; Vasapollo, Claudio; Giovanardi, Otello; Raicevich, Saša; Celic, Igor; Vrgoč, Nedo; Isajlovic, Igor; Jenič, Aljaž; Marčeta, Bojan; Fabi, Giann