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Field studies were conducted in the Patuxent River, Maryland, to quantify the bycatch of cloth-funnel eel pots with small and large openings, and to test the effect of a prototype bycatch reduction device on bycatch and catch.  The bycatch reduction device consisted of a 77 mm PVC ring that was rigged around the narrow end of the flexible eel pot entrance and was designed to physically exclude terrapins. Eel pots fitted with these bycatch reduction devices eliminated the bycatch of terrapin turtles but had no effect on the size or number of eels caught.

Tests were conducted aboard small (<10 m long) static net fishing vessels targeting monkfish off the coast of Britain to determine the response of cetaceans to pingers.  AQUAmark 100 pingers were positioned at 200 m intervals on the net and acoustic click detectors (C-PODs) were placed at the end of 1 km tiers of the net to determine the response of cetaceans to the pingers.  Only one harbour porpoise was incidentally caught during these trials and there was a significant reduction in the number of porpoise clicks recorded at nets with pingers compared to those without.

Research was conducted in the western North Atlantic Ocean to determine what effect changes to the hook design and bait type would have on pelagic longline  bycatch.  Three types of hooks, 18/0 and 20/0 circle hooks and 10/0 Japanese tuna hooks with squid and mackerel bait were tested against the standard 9/0 J-hook with squid bait.  Circle hooks and mackerel bait, individually, significantly reduced loggerhead and leatherback sea turtle bycatch.

Longlines with baited hooks affixed with a block of metal alloy (Nd/Pr) were tested against hooks with a lead weight attached (control), to determine their ability to repel sharks.  Two experiments were conducted in Hawaiian waters, one in the Southern California Bight (SCB) and and one in the Eastern Tropical Pacific off the coast of Eduador.  Significant differences were only found for juvenile hammerhead sharks targeted in one of the Hawaiian experiments.

A modified longline system with a net sleeve and weight on the secondary vertical line was tested in the Chilean Patagonian toothfish fishery. A net sleeve that deploys to cover the fish/hook when hauled and a weight were attached to the vertical hook line. The net sleeve significantly reduced depredation of fish by killer whales (Orcinus orca) and sperm whales (Physeter macrocephalus). The weighted line also was able to reduce seabird bycatch deaths to zero.  

The Patagonian toothfish longline fishery in the Southwest Atlantic suffers from depredation of fish by sperm whales and high bycatch rates of seabirds. This study assessed depredation and seabird bycatch using a modified longline with an "umbrella" net sleeve system with stones for faster sinking. The "umbrella-and-stones" system was effective for preventing bycatch and appeared to restrict depredation, but catches were significantly reduced.  

A new toothless dredge design called the "Newhaven" was tested in the Isle of Man queen scallop fishery, to determine it's effect on both catch and bycatch.  This new dredge design caught significantly more queen scallops compared to the traditional tooth dredge.   However, there was no significant difference between the abundance of bycatch between the two dredge designs.  Bycatch species composition between the two dredge types was relatively similar but the "Newhaven" dredge did catch a significant number of dogfish.

The presence of permanent magnets on hook and line and inshore longline gear was tested for its ability to reduce the bycatch of sharks and rays.  Neodymium-iron-boron magnets were affixed to hook and line gear and barium-ferrite magnets were attached to longline gear.  Both types of fishing gear showed species specific responses but overall elasmobranch capture was significantly reduced when magnets were used.

At-sea and on-shore trials were conducted to test the safety and effectiveness of an alternative line weight called the Safe Lead.  This new line weight is designed to reduce danger to the crew in the event of a bite-off by sliding down or off the line.  At-sea trials were conducted in South Africa and indicated that dangerous fly-backs, a result of a bite-off, were reduced when the Safe Lead was used. During these trials, only 4.2% of Safe Lead fly-backs reached the fishing vessel, compared to 73.3% with traditional leaded swivels.

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.

This investigation details an unusual encounter with a lunge-feeding minke whale with fresh entanglement-like injuries to its head and ventral pouch.  It also discusses results from a short-term comparative study that tested whether the whale fed differently than five uninjured minke whales feeding in the same area.  Collectively, this study: 1) quantifies how much a rope-like injury can restrict the expansion of a minke's ventral pouch while feeding, 2) provides the first minke whale lunge-feeding velocities from a photogrammetric method using digital video, and 3) describes a ne

The Patagonian toothfish longline fishery has high levels of depredation by killer and sperm whales, which puts the whales at risk of being bycatch. Observations from 2003 to 2008 revealed significant variations of interaction rates with killer whales between vessels, suggesting the influence of operational factors on vessel interaction and depredation. When killer whales were absent at the beginning of the line hauling process, short lines (<5,000 m) provided higher yield and were significantly less impacted by depredation than longer lines.

A Double-FAD design was tested for it's ability to mitigate the incidental capture of bigeye tuna in purse fisheries of the Western and Central Pacific Ocean.  The design consisted of two separate FADs with underwater light stimuli attached.  The number of animals caught was not large enough to conduct statistical analyses, but based on the weight of fish, the size proportion of skipjack, yellowfin and bigeye was bigger using the Double-FAD design comapared to the normal design.

Acoustic pingers, Fumunda F3 (2.7 kHz) for humpback whales and F10 (10 kHz) for dolphins, were used on sharks nets within the Queensland Shark Control Program.  Sound from the acoustic pingers was present for around 1.5 km beyond the nets. Humpback whales and dugons were able to hear the F3 pinger 90 m from the net and its two harmonic overtones (5.4 and 8.1 kHz) 10 and 210 m from the net respectively. The F10 pinger was audible to both species up to 130 m from the net. Dolphins could hear the F3 pinger 45 m from the net and it's two overtones 10 and 110 m from the net.

A study was conduceted to test the effect of SaveWave acoustic deterrent devices on target fish catch and bottlenose dolphins in the North Carolina Spanish mackerel gillnet fishery. Observations were carried out on commercial vessels and focal visual and acoustic follows of dolphins were conducted. Fish catches were significantly lower when dolphins were observed interacting with gillnets. The SaveWave device did not affect fish catch. Dolphins were less likely to interact with gillnets and more likely to echolocate when SaveWaves were present.

Gear modifications to the Loligo squid trawl net were developed to reduce scup bycatch.  Two extension modifications, vee and ring excluders, were developed to aid in reducing scup bycatch when large schools are encountered.  These extensions were based on the grid/gate design but made flexible enough to be wound up. The extensions work as an obstruction device and are flanked by fisheyes, which allow the fish to escape.  Previous trawl net modifications were unable to reduce scup bycatch when large schools entered the gear.