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Use of ferrite magnets did not act as a deterrent for blue shark (Prionace glauca) bait strikes. Time to strike, number of prior interactions, number of sharks present, and number of people in the water also did not influence bait strikes. 

40 trial tows investigated the potential of excluder grids in mitigating bycatch in trawl fisheries in the Northern Levant Sea. Tested gear configurations included a flexible grid with 50mm bar spacing and a rigid grid with 95mm spacing within the trawl extension. The excluder grids significantly reduced bycatch of several elasmobranch species including the velvet-belly lanternshark (Etmopterus spinax) and the blackmouth catshark (Galeus melastomus), as well as some species of bony fish. Sea turtle bycatch also appeared to be reduced although in general, sea turtle bycatch during the trials was low (two individuals in the control gear). However, catch performance of target shrimp species (Aristaeomorpha foliacea and Aristeus antennatus) were also reduced in the gear equipped with BRDs, indicating a trade-off. 

Elasmobranch bycatch significantly decreased in bottom-set gillnets in the Gulf of California, Mexico using orange LEDs, ultraviolet LEDs, green LEDs, and green glow sticks, with orange LEDs being the most effective at reducing bycatch. As a whole, catch of bony fish was not affected by illumination, although responses were taxonomic-specific.  

Hook appendages (16/0 size circle hooks modified with stiff wire extending from their shank at either a 22° or 45° angle in relation to the hooks’ offset and non-offset sides) have the potential to reduce yelloweye rockfish (Sebastes ruberrimus) and Pacific spiny dogfish (Squalus suckleyi) bycatch in the U.S. West Coast Pacific halibut (Hippoglossus stenolepis) longline fishery. Hooks with a 45° appendage on the non-offset side caught significantly fewer rockfish, Pacific spiny dogfish, and smaller Pacific halibut without impacting legal-sized halibut catch. The appendages change the shape of the hook and greatly reduce the available opening for a fish’s mouth to engage with the hook, which may make it more difficult for fishes with vertical mouths (e.g., dogfish and rockfishes) than fish with horizontal mouths (e.g., halibut) to be caught using this method.  

This study tested whether a zinc/graphite galvanic electric field reduced capture of elasmobranchs in demersal and pelagic longline fisheries in Florida and Massachusetts (United States). The catch per unit effort of demersal sharks in Florida using the zinc/graphite treatment was significantly lower than the controls, with a 62.3-69.5% reduction in sharks caught on the zinc/graphite treatment. However, there was no difference in  demersal shark CPUE between treatments in Massachusetts. Too few sharks were captured in the pelagic longline trials to allow statistical comparison; however, capture of targeted bony fishes was greatest on hooks with the zinc/graphite treatment, suggesting no negative effect on target catch rates.  Additionally, there was an observed difference in efficacy of the zinc/graphite between Carcharhiniform sharks (more effective) and the Squaliform sharks (less effective), which suggests that the response to this deterrent may be species-specific. Further testing is needed to understand the limitations of the gear and efficacy for pelagic species. 

This study documents the performance of "trap-lines" used in place of traditional hook-based baits in the Mediterranean swordfish (Xiphias gladius) pelagic longline fishery. Trap-lines consist of concentric monofilament rings combined with artificial bait, and operate using entanglement, rather than hooking. Trap-lines were used on 30% of the fishing units, but accounted for about 51% of the marketable catch, with significantly higher catch per unit effort (CPUE) compared with conventional hooks. Landings per unit effort and median fork length were also larger for trap-lines. Additionally, 95% of non-target catch was associated with standard hooks. These early findings highlight the potential of trap lines to increase fishing efficiency, improve size selectivity, and significantly reduce bycatch in the Mediterranean swordfish fishery. 

Tests with captive, as well as wild, juvenile sandbar sharks (Carcharhinus plumbeus) were undertaken to determine the effectiveness of electropositive metals in reducing the interactions with longline gear.  Electropositive metals deterred feeding in groups of captive juvenile sharks for a short period of time and altered the swimming patterns of individuals when food motivation was not present.  In the field, electropositive metals placed within 10 cm of the bottom longline hooks reduced the catch of sandbar sharks by around two thirds, compared to the catch on hooks with a placebo.

Tests with captive, as well as wild, juvenile sandbar sharks (Carcharhinus plumbeus) were undertaken to determine the effectiveness of electropositive metals in reducing the interactions with longline gear.  Electropositive metals deterred feeding in groups of captive juvenile sharks for a short period of time and altered the swimming patterns of individuals when food motivation was not present.  In the field, electropositive metals placed within 10 cm of the bottom longline hooks reduced the catch of sandbar sharks by around two thirds, compared to the catch on hooks with a placebo.

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.

This study evaluated the impacts of hook size on catch of discards of reef in the bottom longline fishery in the eastern Gulf of Mexico. Larger 15/0 hooks successfully reduced primary target species (red grouper, Epinephelus morio) discards by 38% in comparison to 13/0 hooks, but decreased catch of other important species, including red snapper (Lutjanus campechanus). 15/0 hooks also significantly reduced catch rates of Atlantic sharpnose shark (Rhizoprionodon terraenovae) and spiny dogfish (Squalus acanthias).