Bycatch is still one of the main sources of anthropogenic mortality of species of conservation concern worldwide. Within the European Community, Member States are required to monitor and mitigate it, in order to insure a truly sustainable use of the marine ecosystem. Between May 2009 and September 2010, Italian National Institute for Environmental Protection and Research (ISPRA) coordinated a monitoring programme of cetacean bycatch in Italian pelagic trawlers (BYCATCH III), funded in compliance with the Regulation (EC) No.812/2004. The National Inter-University Consortium for Marine Sciences (CoNISMa) and the CNR- ISMAR of Ancona were the two main partner of this programme. Eight independent observers monitored 39 fishing boats for a total of 528 days at sea and 2,254 hauls. The average observation coverage was 2.5% of the national fishing effort. All bycatch events were recorded in the northern Adriatic Sea (GSA 17). No bycatch was observed for cetaceans; whereas 37 loggerhead turtles were caught in the net (bycatch rate =0.022 ind/haul). These were all released alive after full recovery. The annual number of bycaught turtles for north Adriatic pair trawler fishing operations was estimated as 801 individuals (CV=0.20, range 1,456-1,696). The area south Goro was confirmed to be an hot spot for this species. The annual bycatch estimates for a number of elasmobranch species were estimated. The spiny dogfish (Squalus acanthias), smooth-hounds shark (particularly Mustelus mustelus), common thresher shark (Alopias vulpinus), blue shark (Prionace glauca), bull rays (Pteromylaeus bovinus), eagle ray (Myliobatis aquila) and pelagic sting ray (Pteroplatytrygon violacea) - some of which are commercial and vulnerable - were taken in rather big numbers and accounted for several tonnes of fished biomass. Genetic analysis on 104 samples of skin of bottlenose dolphins from the entire Adriatic Sea, seems indicating the existence of a sub-structure for this population. In order to confirm these preliminary indications additional sampling in the southern part of the basin is strongly recommended. Finally, given the existing rate of interaction between pair trawls fishing operations and protected species and species of conservation concern, there is a real urgency to determine whether or not the observed and estimated scale of bycatch events and related stress are sufficient to pose a threat at the population level.
La cattura accidentale è universalmente considerata una delle principali cause di mortalità prodotte dalla attività umana su specie di interesse conservazionistico. All'interno della Comunità europea, gli Stati membri sono tenuti a controllare e mitigare questo fenomeno, al fine di assicurare un uso realmente sostenibile dell'ecosistema marino. Tra maggio 2009 e settembre 2010, l'Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA) ha coordinato un programma di monitoraggio di catture accidentali di cetacei durante la pesca con il traino pelagico (BYCATCH III), finanziato in conformità con il Regolamento (CE) No. 812/2004. Partner di questo programma erano il Consorzio Interuniversitario per le Scienze del Mare (CoNISMa) e il CNR-ISMAR di Ancona. Nel periodo indicato otto osservatori indipendenti hanno monitorato 39 imbarcazioni per un totale di 528 giorni in mare e 2.254 cale osservate. La copertura di osservazione si è aggirata sul 2% dello sforzo di pesca nazionale. Tutti gli eventi di cattura accidentale sono stati registrati nel Mare Adriatico Settentrionale (GSA 17). Nessun'evento di cattura è stato registrato per i cetacei, mentre sono state catturate 37 tartarughe comuni (Caretta caretta) (tasso di cattura=0.022 ind/cala). Queste tartarughe sono state rilasciate vive dopo completo recupero. Il numero di tartarughe catturate accidentalmente in Adriatico settentrionale è stato stimato in 801 individui (CV=0.20, IC 95%=1,456-1,696). La zona a sud di Goro è stato confermato come hot spot per questa specie. Si sono anche stimate le catture accidentali totali annuali per un certo numero di specie di elasmobranchi. Lo spinarolo (Squalus acanthias), il palombo (in particolare Mustelus mustelus), lo squalo volpe (Alopias vulpinus), la verdesca (Prionace glauca), la vaccarella (Pteromylaeus bovinus), l'aquila di mare (Myliobatis aquila) ed il trigone viola (Pteroplatytrygon violacea) - due delle quali sono specie commerciali e vulnerabili - raggiungono stime piuttosto elevate che costituiscono una notevole biomassa sottratta all'ecosistema marino. L'analisi genetica su 104 campioni di pelle di delfini raccolti da tutto il Mar Adriatico, sembra indicare l'esistenza di una sottostruttura per questa popolazione. Per confermare queste indicazioni preliminari è fortemente raccomandato un prelievo supplementare nella parte meridionale del bacino. Infine, dato il tasso attuale di interazione tra le operazioni di pesca con traino pelagico a coppia e le specie protette e/o specie di interesse conservazionistico, c'è una reale urgenza di determinare se la scala di quanto osservato e stimato ed i relativi stress sono sufficienti a rappresentare una minaccia alla livello di popolazione.
Valutazione delle catture accidentali di specie protette nel traino pelagico (BYCATCH III)
De Carlo F;Lucchetti A;Sala A;
2010
Abstract
Bycatch is still one of the main sources of anthropogenic mortality of species of conservation concern worldwide. Within the European Community, Member States are required to monitor and mitigate it, in order to insure a truly sustainable use of the marine ecosystem. Between May 2009 and September 2010, Italian National Institute for Environmental Protection and Research (ISPRA) coordinated a monitoring programme of cetacean bycatch in Italian pelagic trawlers (BYCATCH III), funded in compliance with the Regulation (EC) No.812/2004. The National Inter-University Consortium for Marine Sciences (CoNISMa) and the CNR- ISMAR of Ancona were the two main partner of this programme. Eight independent observers monitored 39 fishing boats for a total of 528 days at sea and 2,254 hauls. The average observation coverage was 2.5% of the national fishing effort. All bycatch events were recorded in the northern Adriatic Sea (GSA 17). No bycatch was observed for cetaceans; whereas 37 loggerhead turtles were caught in the net (bycatch rate =0.022 ind/haul). These were all released alive after full recovery. The annual number of bycaught turtles for north Adriatic pair trawler fishing operations was estimated as 801 individuals (CV=0.20, range 1,456-1,696). The area south Goro was confirmed to be an hot spot for this species. The annual bycatch estimates for a number of elasmobranch species were estimated. The spiny dogfish (Squalus acanthias), smooth-hounds shark (particularly Mustelus mustelus), common thresher shark (Alopias vulpinus), blue shark (Prionace glauca), bull rays (Pteromylaeus bovinus), eagle ray (Myliobatis aquila) and pelagic sting ray (Pteroplatytrygon violacea) - some of which are commercial and vulnerable - were taken in rather big numbers and accounted for several tonnes of fished biomass. Genetic analysis on 104 samples of skin of bottlenose dolphins from the entire Adriatic Sea, seems indicating the existence of a sub-structure for this population. In order to confirm these preliminary indications additional sampling in the southern part of the basin is strongly recommended. Finally, given the existing rate of interaction between pair trawls fishing operations and protected species and species of conservation concern, there is a real urgency to determine whether or not the observed and estimated scale of bycatch events and related stress are sufficient to pose a threat at the population level.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
