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Underwater hook release one step closer

With the generous support of the Auckland Zoo Charitable Trust, we have helped trial a machine that could be a groundbreaker in addressing seabird deaths in tuna longline fisheries. The machine sets longline hooks by stealth underwater and out of sight of seabirds. The idea first occurred to New Zealand tuna fisherman Dave Kellian twenty years ago and thanks to the tireless effort of many individuals a machine now exists that can do just that. In late 2019 the machine was fitted to a New Zealand fishing boat owned by Altair Fishing to do final testing of such things as crew safety and reliability. During an earlier trial in the South Atlantic, seabird scientist Graham Robertson observed that by releasing baited hooks out of sight, underwater the visual cues for seabirds are removed. “They just lose interest and fly away” he said. The true test of the trial was whether the vessel owner was satisfied with the performance of the machine and prepared to continue using it. The good news is he was and the second test will involve a longer period fishing to ensure the crew are completely happy with it in all conditions. It will also include periods with independent observers monitoring the machine and the response of seabirds when other seabird deterrents are removed. The underwater bait setter is a stern-mounted, hydraulically-operated device. Baited hooks are carried underwater in a steel capsule connected to hydraulic winches by Spectra® rope. Baits are flushed from the capsule with water pressure from a spring-loaded door in the bottom section of the capsule, allowing release of baited hooks beneath the dive depths of albatrosses and petrels. The trial has been funded by Auckland Zoo Charitable Trust the Department of Conservation, Fisheries New Zealand, Fisheries Inshore New Zealand. For more info check out Skadia Technologies


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