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Two new branch weighting techniques were tested aboard Australian pelagic longline vessels to determine their effect on catch rates of both target and non-target species and their potential use for seabird mitigation.  The two new branch lines included one with a 120 g lead weight < or equal to 2 m from the hook or a branch line with a 40 g lead weight placed at the hook.

Odontocete (i.e. toothed whale) interaction with longline fisheries is a global phenomenon that threatens the status of some populations and the economic viability of longline fisheries. This review paper summarizes the trend and geographical extent of interactions, the potential impact on odontocetes and fisheries, and describes potential acoustic and physical mitigation solutions. 

Two devices were designed to prevent odontocetes from depredating caught fish and putting themselves at-risk of becoming bycatch. One device used physical deterrence by shouding the fish with a barrier and the other used psychological deterrence by utilizing prior negative experiences of temporary entanglement in fishing gear. Both devices fit on a branchline at a distance from the hook and descend towards a caught fish using a line tension trigger mechanism.

An acoustic device designed to deter false killer whales from approaching longlines by reducing the whales' echolocation performance capabilities was tested on a trained false killer whale. The device, Longline Saver, produced a series of complex, broadband signals (1-250 kHz) at high intensity levels (up to 182 dB). The whale was asked to detect a target in the presense or abscence of the acoustic device. Initially, the device reduced the whale's echolocation performace to chance levels, however subsequent trials demonstrated improvement in echolocation.  

A study was conducted aboard the Cornish inshore gillnet fishery to determine if pingers could reduce porpoise and bottlenose dolphin bycatch, whether habituation to the pingers would reduce their effectiveness and how quickly porpoises and dolphins recolonise a pingered site after their removal. Vessels were equipped with passive acoustic monitoring systems that can recognize and log each animals click and AQUAmark 100 pingers were spaced 200 m apart on the nets.  Control nets with no pingers were also used.