Development of an underwater setting method for surface longliners, to minimise the accidental capture of seabirds

In response to the Department of Conservation's concerns for the accidental capture of seabirds by Surface Long Liners and subsequent contract 9513004, several concepts of bait placement devices were evaluated. Two methods being selected for further in depth evaluation.
The first concept being a towed paravane with an endless cable employed to transport and release the bait at the depth to which the paravane was set. Although practical bait carrying devices were designed, the ability to retrieve the endless cable and paravane proved problematical. At this point this concept was abandoned.
The second concept being a transportation capsule which clamps the baited snood until the capsule reaches its determined depth. At this point in time the carry over action of the capsule and retrieval action would release the bait. This design concept proved worthy of construction and trial. Sea trials of this device proved successful with a 100 percent bait release rate achieved.