Indicative trends in by-catch of sharks in the CAMLR Convention Area

Conservation Measure 32-18 on the conservation of sharks specifies that “directed fishing on shark species in the Convention Area for purposes other than scientific research, is prohibited.” Further, that “any by-catch of sharks shall, as far as possible, be released alive.”  Here, we examine trends in shark by-catch in the CAMLR Convention Area using information reported by vessels and scientific observers from the 1996–2017 fishing seasons. While there appear to be substantial gaps in the shark by-catch reported by both sources, the available data suggests that shark by-catch may have increased during the last 10-year period, with most of the by-catch reported in Division 58.5.2 and substantially lower catches in other statistical management areas. We highlight issues, some of which are in relation to catch in weight vs. numbers, retained, discarded, and released shark by-catch, and in the comparison of data from vessels vs. scientific observers. This paper provides information that could be useful during consideration of CCAMLR-XXXVII/30 by the Scientific Committee and Commission.