Improving reliability of species identification and logbook catch reporting by commercial fishers in an Australian demersal shark longline fishery

Large adult carcharhinid and sphyrnid sharks have been targeted in coastal waters off New South Wales, eastern Australia, by commercial fishers using demersal longlines since 2005. Inaccurate fisher reporting of the composition of catches led in 2008 to a range of complementary management measures to help improve reliability, including a redesigned catch logbook, species identification guide and at‐sea education via an observer programme. This study provides results from assessments of the effectiveness of those measures. A questionnaire yielded overwhelmingly positive feedback from fishers regarding the usefulness of the species identification guide. Comparison of observer‐recorded data and corresponding fisher‐reported logbook data via weighted linear mixed‐effects modelling found that since 2008, misreporting of catches has varied considerably among species and, for some species, among fishers. With some species commonly under‐reported and others frequently over‐reported, it is apparent that certain species were likely mistaken for other morphologically similar species. Such systematic error inherently undermines stock assessments of these vulnerable species. Management strategies designed to include education and extension will ensure greater reliability of fisher reporting of shark catches in the future.