Reviewing effectiveness of management measures on shark landings in Sri Lanka over past five years
Sharks play an important role in the marine fishery of Sri Lanka. Though shark fishery was a target fishery in the past, it has become a non-target fishery at present. Sharks are mostly caught as a by-catch in the tuna fishery. The production statistics over the last five years (2013-2017) provided by the large pelagic fishery database (PELAGOS) of Sri Lanka was used to analyze the recent trends in the shark fishery. Recent regulations imposed on banning of three thresher shark species with oceanic white tip shark and whale shark have resulted a considerable decline in the shark landings. At present, the percentage contribution of shark production to large pelagic fish production has become less than 2%. During the past, it remained even around 5%. The shark catches in terms of number of species at present are not diverse like reported in the past. The shark catches over the last five years are mainly comprised of silky sharks (Carcharhinus falciformis) (57%) followed by blue sharks (24%) and scalloped Hammerhead sharks (Sphyrna lewini) (5%) respectively. Though the silky shark was the dominant species in recent years, blue shark (Prionace glauca) landings dominated in 2017 by an increase of around 7% than silky sharks. Landings of Silky sharks were peaked in 2013 (1 247Mt) and after, there was a considerable decline in the silky shark catches reported both within Exclusive Economic Zone (EEZ) of Sri Lanka and in high seas. But, there is an increase trend in the blue shark landings mainly reported within the EEZ of Sri Lanka. During the past decade, most of the shark species have been caught mainly by longline-gillnet gear combination. During 2013 - 2017, longline has become the dominant fishing gear responsible for higher shark landings. At present, more than 80% of silky sharks are caught by longline. This study reveals that shark catches have considerably declined over last five years and recent conservation and management initiatives on sharks implemented by Sri Lanka could be one possible reason for this nature. At present, Sri Lanka is in the process of reviewing the previous National Plan of Action (NPOA) implemented with the aim of conservation IOTC-2018-WPEB14-43_Rev2 and management of sharks and a new NPOA will be formulated accordingly for further strengthening the research, conservation and management of sharks.