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The catches from five experimental trawls (TED + fisheye BRD, upward facing TED, downward facing TED, bigeye BRD and square-mesh panel BRD) were compared to those of the standard twin Florida Flyer prawn trawl. Nets with a combination of a TED and BRD reduced sea turtle catches by 100%, large sponges by 85.3%, sharks by 36.3% and rays by 17.7% and reduced the proportion of soft and damaged prawns by 41.6% and catches of tiger prawns by 6.5%. Upward and downward facing TED's reduced sea turtle bycatch by 99% and 100% respectively and large sponges by 81.6% and 95.9% respectively.

Codends modified with rectangular mesh panels (one oriented length-wise in the cod end and one oriented width-wise, each measuring 7 x 11 bars) reduced the weight of discarded bycatch by 46% and 38% respectively but did not significantly reduce the catch of targeted prawns. A haulback delay of 10-15 seconds allowed juvenile red spot to escape through the square mesh panels, while trawls with no delay showed no significant reduction in the bycatch of this species.

Gillnets with three difference mesh sizes (2 7/8", 3" and 4") were modified to use 200 lbs/200 yard lead line and 11 oz buoyancy floats (versus 50lbs/200 yard lead line and 3 oz floats) to increase the tension in the net. Catch rates of Atlantic sharpnose and bonnethead sharks were significantly lower in the 4" modified net. The proportion of hammer-wrapped bonnethead sharks was significantly higher in the 4" unmodified net and significantly less blacktip sharks were wrapped in the 3" modified net. Selectivity of blacknose sharks varied between the modified and unmodified nets.

White Dukane pingers with a fundamental frequency of 10kHz and harmonies of up to 160 kHz, elicited the strongest response from Hector's dolphins, compared to the black Pice and red Dukane pingers. More than half (62.5%) of the dolphins exhibited avoidance when exposed to the white pinger. However, no significant differences between pingers were found in the rate of echolocation clicks per dolphin or dolphin group, or among the peak frequencies of subset clicks.

Tests were conducted to determine if twin trawl nets containing a Turtle Excluder Device (TED) and a Popeye Fishbox caught less bycatch then nets fitted only with a TED. Nets that had the Popeye Fishbox located 70 meshes from the codend draw strings had a 48% reduction in the weight of small bycatch, an 87% reduction in number of sea snakes and a 35% reduction in the number of sharks and rays caught. When the Popeye Fishbox was placed 100 meshes from the codend draw strings, the weight of small bycatch was reduced by 28% and the number of sharks and rays was reduced by 27%.

The addition of a filter grid (inclined at ca. 20 degrees) that leads to an escape tunnel in trawl nets allowed 100% of rays and turtles to escape, 75% of manta rays, 40% of billfish and between 20-75% of sharks to escape.

Bottom set gillnets with pingers (LU-1, 8 signals, 145 dB, 300 ms, random signal intervals) attached were tested against standard nets and nets with dummy pingers (double blind) to determine if they could reduce the incidental capture of harbour porpoises. The proportion (number of nets with porpoises/number without) of harbour porpoise bycatch was reduced from 0.00229 and 0.00295 for nets with dummy pingers and no pingers respectively, to 0.00015 for nets with active pingers.

Several versions of a terrapin excluder design were tested on crab traps to determine how effective they were in reducing terrapin bycatch and what the effect on catch rates of targeted crabs was. All tests consisted of modified and unmodified traps being set in an alternate fashion. A wire bar placed across the opening of the traps was unsuccessful in reducing terrapin bycatch. A second design, which was a rectangular frame (5x10 cm) was successful.

A new otterboard door design (Clarck-Y door) was tested in both flume tanks and at sea to compare its possible impact on the seabed compared to an existing door (Cambered vee) design. The two doors had a similar behavior with regard to the attack angle and the magnitude of drag, lift and efficiency coefficients in the flume tank experiment. In the sea trials, the Cambered vee door had higher values for the drag and lift coefficients than the Clarck-Y door and the horizontal door spread was also higher in the Cambered vee compared to the Clarck-Y door.

In northern hemisphere trawl fisheries, little is known about the extent of cable strike seabird mortality or techniques to mitigate it. We compared the rate of heavy seabird strikes by third-wire cables and warps, using three mitigation measures compared to a control of no mitigation. Experiments were conducted aboard two catcher-processor vessels targeting walleye pollock (Theragra chalcogramma) in the eastern Bering Sea: one that rendered offal into fish meal and fish oil (Vessel R) and one that minced offal prior to discharge (Vessel M).

Average annual seabird bycatch has declined by 73% in the last 5 years (2002-2006) compared to bycatch from the late 1990s. Despite the recent reductions resulting from mandatory mitigation requirements, seabirds continue to be caught at higher rates than would be expected given results of controlled studies that demonstrated bycatch reductions of nearly 100% with paired streamer lines. The results of this study demonstrate that a few individual vessels continue to be responsible for the majority of seabird bycatch.

Visual cues are important in sea turtle foraging behavior and likely influence their interaction with fishing gear. This studey examined the potential effectiveness of three visual cues: 1) shark shapes, 2) illumination of nets by LED lights, and 3) nets illuminated with chemical lightsticks - for reducing green sea turtle bycatch in gillnets. The presence of shark shapes significantly reduced mean sea turtle catch rates by 54%, but also reduced target catch by 45%. Nets illuminated with LED lights significantly reduced sea turlte bycatch by 40% and had negligable impact on target catch.

Circle hooks and J-style hooks were tested on pelagic longline vessels (US Atlantic) to determine if the use of circle hooks reduced bycatch mortality while maintaining target species catch rates.  0⁰ offset circle hooks were determined to increase the survival of bycatch species at haulback while having little impact on target species catches.  Specifically, J-style hooks had a significantly higher total overall catch rate.  Catch rates of yellowfin tuna in the fall were higher (significantly) for circle hooks and pelagic stingrays (spring caught) were the only sp