Development of an Underwater Bait Setter

1. This paper summarises recent progress and future work relating to the development,
construction and testing of a device that sets hooks several metres underwater to avoid
detection by seabirds.
2. The underwater setter is a stern-mounted hydraulically-driven device. It comprises
components that are fixed to the vessel and a component (a capsule that holds the baited
hook) that is driven down into the water column each time a hook is set. This design is
the most fuel efficient method of delivering baited hooks at required depths underwater
because it minimises the drag associated with devices that remain underwater while
setting (e.g., underwater setting chutes). The device is modular and can be readily retrofitted
to most tuna fishing vessels after their construction.