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title: "A newly-developed underwater bait setter aims to stop albatrosses and petrels being killed by pelagic longline fisheries"
---

# A newly-developed underwater bait setter aims to stop albatrosses and petrels being killed by pelagic longline fisheries

Graham Robertson ([Australian Antarctic Division](http://www.antarctica.gov.au/), Kingston, Tasmania) and colleagues write open-access in the [*Open Journal of Marine Science*](http://www.scirp.org/journal/ojms/)on the development of an underwater bait setter to deliver pelagic longline hooks to depths out of the reach of albatrosses and petrels.

 The paper’s abstract follows:

 “Longline fisheries for tunas and tuna-like species present an existential threat to many populations of albatrosses and petrels worldwide.  To prevent this form of mortality we developed a new technology designed to deploy baited hooks underwater beyond the dive depths of seabirds (6 – 10 m for the species most commonly caught).  The underwater bait setter is a stern-mounted, hydraulically-operated and computer-controlled device that catapults baited hooks underwater in a steel capsule connected to hydraulic winches by Spectra® rope.  Baits are flushed from the capsule by water pressure through a spring-loaded bait release door.  The chief engineering challenges in the developmental stages were ensuring: 1) bait delivery to target depths with cycle times (time from release to recovery) that were practical for fishing operations; 2) bait retention in the capsule (no drop-outs) on the descent phase of the cycle; 3) baits, upon release at target depth, were not drawn up the water column on the capsule recovery phase (from possible hook-ups and/or suction); and 4) the retention of baits on hooks post-release from the capsule was not affected by the mechanical release underwater.  Operational trials with the final version of the capsule yielded satisfactory cycle times to depths of 6 - 10 m.  All baits were retained in the capsule on the descent and released as required at target depths (n = 606 deployments).  Bait retention on hooks post release from the capsule and retention on hooks hand-set at the surface (the conventional method) were statistically indistinguishable.  The underwater bait setter is modular in construction and can be fitted to all types of vessel sterns.”

 ![](https://www.acap.aq/images/stories/acap/Birds/Petrels/W/White_chinned/white_chinned_petrel_hooked_by nicolas_gasco.jpg)

 The problem: a White-chinned Petrel caught on a longline hook

 Photograph by Nicolas Gasco

 With thanks to Barry Baker for information.

 **Reference:**

 Robertson, G., Ashworth, P., Ashworth, P., Carlyle, I. & Candy, S.G.  2015.  The development and operational testing of an underwater bait setting system to prevent the mortality of albatrosses and petrels in pelagic longline fisheries.  [*Open Journal of Marine Science* 5: 1-12](http://www.scirp.org/Journal/PaperInformation.aspx?PaperID=52452#.VKy2RyuUclA).

 *John Cooper, ACAP Information Officer, 07 January 2014*