Trialling the new Hookpod-mini, configured to open at 20 m depth, in pelagic longline fisheries off southern Brazil

From July 2018 to November 2019, 12 trips on pelagic longline vessels off southern Brazil were monitored by on-board observers, comprising a total effort of 137 sets and 159,250 hooks. Five trips were on-board ‘control vessels’, totalling 65 sets and 77,651 hooks, and seven trips were on-board ‘Hookpod vessels’, which deployed Hookpod-mini (configured to open at 20 m depth) and regular (control) branchlines simultaneously in the longline settings. These trips served to compare the effects of Hookpod in relation to control gear, which comprised 72 sets and 81,989 hooks, of which 45,289 (55%) were Hookpod hooks and 36,700 (45%) were control hooks. In total, 10 seabirds (BPUE = 0.13) were caught during five trips on board ‘control vessels’ (6 black-browed albatrosses, 3 white-chinned petrels and 1 wandering albatross). On board ‘Hookpod vessels’, there was no seabird bycatch in the Hookpod gear and two seabirds (black-browed albatrosses) were caught on the control gear (BPUE = 0.05), and there was no significant effect of Hookpod on turtle bycatch and target species catches. Our findings reinforce the effectiveness of the Hookpod as a standalone seabird bycatch mitigation measure, without increase the bycatch of other taxa of concern (turtles) neither reduce the catchability of target species.