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Summary:

To reduce turtle interactions, regulations for the Hawaii (U.S.)-based longline swordfish (Xiphias gladius) fishery required vessels to switch from using a J-shaped hook with squid bait to a wider circle-shaped hook with fish bait. Analyses of observer data showed that, following the introduction of the regulations, significant and large reductions in sea turtle and shark capture rates occurred without compromising target species catches. There was also a highly significant reduction in the proportion of turtles that swallowed hooks and a highly significant increase in the proportion of caught turtles that were released after removal of all terminal tackle. Research suggests that turtles aggregate at foraging grounds and that instituting methods to avoid real-time turtle bycatch hotspots may further reduce turtle interactions.

Summary:

This study is based on seventeen years of fishery observer data collected aboard drift gillnet vessels fishing for swordfish and sharks in the California Current (United States). Since use of acoustic pingers began in 1996 (source level ∼135 dB RMS, re: 1 Pa @ 1 m, frequency 10–12 kHz, pulse duration = 300 ms, pulse interval = 4 s), there have been no beaked whale entanglements through 2006, in comparison to 33 entanglements from 1990-1998. 260 cetaceans representing 12 other species were observed entangled in the fishery from 1996-2006. 

Summary:

A hydrodredge was tested using water pressure created from the hydrodynamics of the gear to lift scallops (Pecten maximus) out of the seabed. When compared to a more traditional dredge, the hydrodredge increased catch of surface-dwelling scallops but decreased catch of deeper-dwelling scallops. Bycatch of starfish, crabs and urchin were less likely to suffer fatal injuries using the hydrodredge.

Summary: Longlines were set at depths greater than 100m using weighted lines to reduce bycatch of recreationally important fish species and protected species such as seabirds and sea turtles. While bigeye tuna catch rates were consistent between control and experimental sets, bycatch rates increased for sickle pomfret and opah but decreased for wahoo, dolphinfish, blue and striped marlin, and shortbill species. These species are generally not targeted but retained for their commercial value. Bycatch of sharks and pelagic stingrays did not differ between the experimental and control sets.

Summary:

Several designs of seal exclusion devices (SEDs) were tested to reduce bycatch of Australian fur seals (Arctocephalus pusillus doriferus) in the winter blue grenadier (Macruronus novaezelandiae) trawl fishery. A 'top-hatch' SED, or one with a top-mounted escape hatch, resulted in the lowest occurrence of seal bycatch than any other SED design or than nets without a SED. The SED prevented entry into the net codend where drownings occurred. SEDs also successfully expelled seals and limited access into the net via the escape hatch. Cameras are needed to verify the results.

Summary:

A rare-earth metal alloy (cerium/lanthanide) was tested to determine if it could reduce bycatch of spiny dogfish (Squalus acanthias) in longlines and rod and reel fisheries in the Gulf of Maine, United States. Laboratory and field trials showed no significant reduction in dogfish catch.

Summary:

Rare earth metals (made of cerium mischmetal) were compared with control treatments of standard circle hooks and inert steel above circle hooks on longline fishing gear to determine if bycatch reduction of spiny dogfish (Squalus acanthias) could be achieved. Results indicated a slight reduction in dogfish bycatch and a greater reduction in catch of longnose skate (Caliraja rhina) on hooks with mischmetal. Problems for using mischmetal commercially include its expense, hazardous nature, and rapid hydrolysis in seawater.

Summary:

Two rare earth metals (neodymium-iron-boride magnets and cerium mischmetal) attached to baited hooks were tested in a laboratory study against inert metal controls to determine the effects on spiny dogfish (Squalus acanthias) and Pacific halibut (Hippoglossus stenolepis). Spiny dogfish attacked and consumed fewer baits with mischmetal than for the control or magnets. Magnets did not deter dogfish from eating baits, and Pacific halibut showed no reaction to either rare earth metal.

Summary:

In 2003 and 2004 the scallop industry, Coonamessett Farm, and the Virginia Institute of Marine Fisheries, with funding from the U.S. National Oceanographic and Atmospheric Administration (NOAA) Fisheries Service, successfully tested a series of chains that excluded turtles from entering the dredge bag. In twelve trials, divers videoed the results of placing turtle carcasses in the path of a modified scallop dredge. Turtle carcasses went over the dredge in all but three trials. Damage was assessed as “slight or none” in all valid assessments of damage to a carcass following an encounter.