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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 assessed the catch and environmental outcomes of modified scallop dredge designs aimed at reducing environmental impact without changing catch efficiency. Four gear designs were tested: N-Viro dredge with conventional belly bag, N-Viro dredge with skid belly bag, Newhaven dredge with skid belly bag, and the standard Newhaven dredge with conventional belly bag (control). Results showed that the N-Viro dredge alone did not increase catches of market-sized king scallops (Pecten maximus); however, pairing it with a skid belly bag improved catches by 14%–19%. The N-Viro dredge reduced undersized scallop catch by 42% and stones by 67%, with further reductions when combined with a skid belly bag. The N-Viro dredge also decreased fuel consumption by about 30%, while the skid belly bag reduced gear footprint by about 55%. Biomass of bycatch was higher for stonier habitats irrespective of the dredge used, however, skid belly bags caught more bycatch than standard belly bags, and this difference was more pronounced when an N-Viro dredge was also used. 

This study tested the efficacy of a modified trawl net in the brown shrimp (P. californiensis) fishery in northern Peru. The modified net was designed to improve selectivity by incorporating 60 mm, 50 mm, and 36 mm mesh sizes, modifications to the net mouth were made to achieve a more pronounced catenary curvature, and the net was constructed primarily from polyethylene in various sections to reduce its overall weight. To further enhance selectivity, an additional footrope was incorporated to facilitate the exclusion of certain benthic species, such as soles, starfish, and other bottom-dwelling organisms. A square mesh window was added 60 cm from the bottom center of the net mouth to allow the escape of snails and crabs. The modified net reduced bycatch by 35% and discards by 50%, while the catch of target species remained unchanged. The reduction in bycatch was not significantly different for species of fish, although catch of this species group was reduced by 24%. 

Experiments were conducted in California to determine the effect of hook type (circle and J-type) on anatomical hook location and subsequent growth and mortality rates of white seabass (Atractoscion nobilis). Juvenile white seabass were captured with 4/0 offset circle hooks, J-type hooks or a control net.  There was a significant difference in hook location between the two types of hooks, with more fish being hooked in the lip with the circle hooks. The majority of mortality occurred in fish with hook damage to the esophagus, but equal numbers of these fish were caught on the two hook types.  Deeply hooked fish died 65% of the time when hooks were removed and 41% of the time when they were left embedded regardless of hook type. White seabass caught on circle hooks grew at a significantly faster rate compared to those caught on J-type hooks or in the control net.  The results suggest catch-and-release mortality should be included in management plans for this species.

An analysis of the performance of circle hooks in comparison to J-style and tuna hooks on the hooking rates of target and non-target species, specifically sea turtles, in the artisanal surface longline fisheries of Ecuador, Panama, and Costa Rica was performed. The target fisheries were mahi-mahi and a combination of tunas, billfishes, and sharks (TBS). In the TBS fishery, tuna hooks were compared to 16/0 circle hooks from Ecuador and Panama and 18/0 circle hooks from Costa Rica. For the mahi-mahi fishery, 14/0 and 15/0 circle hooks in Ecuador and 16/0 circle hooks in Costa Rica were compared to traditional J-style hooks. Circle hooks reduced sea turtle hooking rates in most of the comparisons. Hooking rates for target and non-target species were not consistent.

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. 

This study evaluated the effectiveness of using plastic drink bottles as low-cost acoustic reflectors to reduce franciscana dolphin (Pontoporia blainvillei) bycatch in bottom-set trammel nets and gillnets off of southern Brazil. The bottles achieved an 88% reduction in dolphin bycatch per unit effort compared to control nets. In addition, the bottles had no significant impact on commercial target species catch (by weight). 

The study tested the use of glass and plastic drink bottles as low-cost bycatch mitigation devices (mechanical pingers and acoustic reflectors, respectively) in gillnet fisheries across three regions/fisheries: surface-set driftnet fisheries in Zanzibar and Peru and bottom-set trammel net fisheries in Brazil. In Brazil, plastic bottles reduced dolphin bycatch while increasing fish catch, although further trials are needed. In Peru, glass bottles had no effect on dolphin, porpoise, or turtle bycatch but altered target elasmobranch and teleost catches; plastic bottles similarly had no effect on dolphin bycatch but increased shark catch. In Zanzibar, no dolphin bycatch was recorded in any sets, though plastic bottles increased tuna catch. 

The study tested the use of glass and plastic drink bottles as low-cost bycatch mitigation devices (mechanical pingers and acoustic reflectors, respectively) in gillnet fisheries across three regions/fisheries: surface-set driftnet fisheries in Zanzibar and Peru and bottom-set trammel net fisheries in Brazil. In Brazil, plastic bottles reduced dolphin bycatch while increasing fish catch, although further trials are needed. In Peru, glass bottles had no effect on dolphin, porpoise, or turtle bycatch but altered target elasmobranch and teleost catches; plastic bottles similarly had no effect on dolphin bycatch but increased shark catch. In Zanzibar, no dolphin bycatch was recorded in any sets, though plastic bottles increased tuna catch. 

The study tested the use of glass and plastic drink bottles as low-cost bycatch mitigation devices (mechanical pingers and acoustic reflectors, respectively) in gillnet fisheries across three regions/fisheries: surface-set driftnet fisheries in Zanzibar and Peru and bottom-set trammel net fisheries in Brazil. In Brazil, plastic bottles reduced dolphin bycatch while increasing fish catch, although further trials are needed. In Peru, glass bottles had no effect on dolphin, porpoise, or turtle bycatch but altered target elasmobranch and teleost catches; plastic bottles similarly had no effect on dolphin bycatch but increased shark catch. In Zanzibar, no dolphin bycatch was recorded in any sets, though plastic bottles increased tuna catch.