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Pelagic longlines targeting bigeye tuna (Thunnus obesus) and lustrous pomfret (Eumegistus ilustris) in Hawaii were weighted with lead weights, enabling fishing deeper in the water column than traditional pelagic longlines.  Weighted longlines caught 31 target species with a slightly higher catch per unit effort (CPUE) of 1.3 fish/100 hooks (49 kg/100 hooks) compared to traditional gear (38 target species and a CPUE of 1.08 fish/100 hooks or 41 kg/100 hooks).  Bigeye tuna CPUE for the weighted gear was higher, 0.95 fish/100 hooks (36 kg/100 hooks), compared to traditional gear, 0.56/100 hooks (21 kg/100 hooks).In a second trial in a fishery targeting tuna and billfish, swordfish (Xiphias gladius) CPUE was very similar for weighted (0.3 fish/100 hooks or 17 kg/100 hooks) and traditional (0.25 fish/100 hooks or 14 kg/100 hooks) gear.  This technique could be used to reduce sea turtle and other bycatch species interactions, however this was not tested during this initial trial study.

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 TEDs reduced sea turtle bycatch by 99% and 100% respectively and large sponges by 81.6% and 95.9% respectively. Catches of tiger prawns (P. semisulcatus and P. esculentus) were reduced by 6.3% with the use of TEDs. The BRDs had little impact on the catch of either target or bycatch species.

Tests were conducted on tuna longline fishing vessels in the eastern Pacific Ocean to determine if the use of J (size 4.0 traditional) or circle hooks (sizes 15, 16 and 18) and different bait resulted in differences in the catch rates of target and bycatch species. No significant differences in catch rates of the target species were found between hook types. Significant differences between J and circle hook size 15 and between J and circle hook size 16 were found in the bycatch species group (all species grouped together). The highest catch rates for tunas were found on circle hooks size 15 and for billfishes on J hooks. The largest circle hook (18) had the lowest catch rates. Squid and jack mackerel bait had the highest catch rates for tunas and other fishes, while chub mackerel bait caught the most billfish and sharks.

Visual cues are important in sea turtle foraging behavior and likely influence their interaction with fishing gear. This study 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 (Chelonia mydas) 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 turtle bycatch by 40% and had negligible impact on target catch. Lastly, nets illuminated with chemical lightsticks also reduced sea turtle catch rates by 60% and had no significant impact on target catch. 

Visual cues are important in sea turtle foraging behavior and likely influence their interaction with fishing gear. This study 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 (Chelonia mydas) 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 turtle bycatch by 40% and had negligible impact on target catch. Lastly, nets illuminated with chemical lightsticks also reduced sea turtle catch rates by 60% and had no significant impact on target catch. 

Visual cues are important in sea turtle foraging behavior and likely influence their interaction with fishing gear. This study 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 (Chelonia mydas) 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 turtle bycatch by 40% and had negligible impact on target catch. Lastly, nets illuminated with chemical lightsticks also reduced sea turtle catch rates by 60% and had no significant impact on target catch. 

An experimental leader design was tested on pound nets in the Chesapeake Bay, United States, in 2004 and 2005 to determine their effectiveness in reducing the incidental catches of sea turtles (Lepidochelys kempi and Caretta caretta). The experimental design consisted of replacing the top two thirds of the traditional mesh panel leader with vertical ropes spaced 61 cm apart. During the study, 21 sea turtles interacted with the control net, while only 1 interaction with the experimental net occurred. In addition, there was no significant differences in the harvest weight or size selectivity of finfish between the two net types, although these results were not considered very robust. 

An experimental leader design was tested on pound nets in the Chesapeake Bay, United States, in 2004 and 2005 to determine their effectiveness in reducing the incidental catches of sea turtles (Lepidochelys kempi and Caretta caretta). The experimental design consisted of replacing the top two thirds of the traditional mesh panel leader with vertical ropes spaced 61 cm apart. During the study, 21 sea turtles interacted with the control net, while only 1 interaction with the experimental net occurred. In addition, there was no significant differences in the harvest weight or size selectivity of finfish between the two net types, although these results were not considered very robust. 

Tests were conducted aboard pelagic longline vessels fishing off the coast of Uruguay, to determine the effect of hook type (circle hook vs J-hook) on the catch and length composition of target and non-target species.  Both American and Spanish style longlines were used during these experiments.  American style longlines consist of a 3.6 mm polyamide monofilament mainline with polyamide or polyester buoys lines 9-36 m long.  Spanish style longlines consist of 5-mm polyethlene multifilament mainline with buoy lines (similar in thickness and material to mainline) 12-18 m long.  On the American style longlines, albacore tuna (Thunnus alalunga) and shortfin mako shark (Isurus oxyrinchus) catches were significantly higher on circle vs J-hooks. Catches of other tunas and sharks (blue (Prionace glauca) and porbeagle (Lamna nasus) were also higher on circle hooks, but were not significantly higher.  There was no significant difference in the catches of seabirds or sea turtles between the two types of hooks on the American style longlines.  On the Spanish style longlines, albacore tuna catches were also significantly higher on circle compared to J-hooks, and there was a significant decrease in pelagic stingray (Pteroplatytrygon violacea) catches on circle hooks.  No significant difference in the catch rates of seabirds or sea turtles was seen between the two types of hooks on this type of longline.  There was no significant difference in the length distribution for any species between the two hook types on either type of longline.  There were also no significant differences between hook types for any hooking location of incidentally caught sea turtles.

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 (Caretta caretta) and leatherback sea turtle (Dermochelys coriacea) bycatch.  Combined, 18/0 circle hooks and mackerel bait reduced loggerhead sea turtle bycatch, while swordfish (Xiphias gladius, a targeted species) catch by weight increased. Combined 18/0 circle hooks with squid bait significantly decreased swordfish catch rates but significantly increased blue shark (Prionace glauca), bluefin tuna (Thunnus thynnus) and albacore tuna (Thunnus alalunga) catch rates.  Blue shark, bigeye (Thunnus obesus) and albacore tuna catch rates were always reduced when mackerel bait was used but porbeagle (Lamna nasus) and shortfin mako shark (Isurus oxyrinchus) catch rates increased with this bait type.