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This article reviewed bycatch mitigation methods that rely on sensory ecology to reduce interactions with sea birds, sea turtles, pinnipeds and blue-water fish. Panels containing patterns of low spatial frequency and high internal contrast can be used for all of these species. These panels are not likely to reduce catches of target species and are easy and inexpensive to apply. The authors suggest that sound signals on gillnets are not recommended for most bycatch species, excpet for cetaceans. Cetaceans require both visual cues and warning through echolocation.

Three types of bycatch reduction devices (BRD) [turtle excluder device (TED), square mesh codend (SMC) and fisheye (FE)] were tested aboard shrimp trawl vessels. Differences in catch from nets equipped with a BRD on one side and a standard net on the other were compared for each of the three BRDs. Use of the TED resulted in no captures of sea turtles or large animals, and did not significantly reduce shrimp catches or fish bycatch. The SMC reduced both shrimp and bycatch catches, although only a reduction in bycatch was significant. The SMC did result in catches of larger shrimp compared to the other nets. The FE significantly reduced shrimp and bycatch catches.

Three types of bycatch reduction devices (BRD) [turtle excluder device (TED), square mesh codend (SMC) and fisheye (FE)] were tested aboard shrimp trawl vessels. Differences in catch from nets equipped with a BRD on one side and a standard net on the other were compared for each of the three BRDs. Use of the TED resulted in no captures of sea turtles or large animals, and did not significantly reduce shrimp catches or fish bycatch. The SMC reduced both shrimp and bycatch catches, although only a reduction in bycatch was significant. The SMC did result in catches of larger shrimp compared to the other nets. The FE significantly reduced shrimp and bycatch catches.

Three types of bycatch reduction devices (BRD) [turtle excluder device (TED), square mesh codend (SMC) and fisheye (FE)] were tested aboard shrimp trawl vessels. Differences in catch from nets equipped with a BRD on one side and a standard net on the other were compared for each of the three BRDs. Use of the TED resulted in no captures of sea turtles or large animals, and did not significantly reduce shrimp catches or fish bycatch. The SMC reduced both shrimp and bycatch catches, although only a reduction in bycatch was significant. The SMC did result in catches of larger shrimp compared to the other nets. The FE significantly reduced shrimp and bycatch catches.

This article describes the design and fabrication of a prototype rope-less fishing system that might be used in the Gulf of Maine lobster fishery. Rope-less fishing gear, which secures vertical fishing lines to the bottom until they are released for hauling, is a potential mitigation measure to reduce vertical line entanglements of marine mammals including North Atlantic right whales, along with leatherback sea turtles. The prototypes consists of a flotation line spool capable of holding up to 900 m of 1/2 in line. The spool is secured to a lobster trawl by a mechanical release that can be triggered for hauling either using a digital timer or acoustic transponder. In addition to the rope-less prototype, the study conducted a preliminary investigation on the passive acoustic detectability of rope-less gear.

Observer data from European purse seine vessels operating in the Atlantic and Indian Ocean (1995-2011) were used to assess spatial and temporal variation in sea turtle bycatch rates. Information from both free swimming school sets and sets made on drifting fish aggregating devices (DFADs) was included in the analysis. Overall the results indicate purse seine fisheries have a very low impact on sea turtles. Annually, 218 and 250 individual sea turtles were estimated to be captured by purse seines operating in the Atlantic and Indian Ocean respectively. The majority, 75%, of these turtles were released alive. The study also suggests that drifting fish aggregating devices (DFADs) may play a role in aggregating juvenile sea turtles.

Researchers deployed LED lights on the floatlines of paired gillnets (control vs illuminated net) during 864 fishing sets using small-scale vessels departing from three Peruvian ports between 2015 and 2018. Bycatch probability per set for sea turtles, cetaceans and seabirds as well as catch per unit effort (CPUE) of target species were analyzed for illuminated and control nets using a generalized linear mixed-effects model (GLMM). For illuminated nets, bycatch probability per set was reduced by up to 74.4 % for sea turtles and 70.8 % for small cetaceans in comparison to non-illuminated, control nets. For seabirds, nominal bycatch per unit effort (BPUE) decreased by 84.0 % in the presence of LEDs. Target species CPUE was not negatively affected by the presence of LEDs. This study highlights the efficacy of net illumination as a multi-taxa BRT for small-scale gillnet fisheries in Peru. 

This study recorded and analyzed vocalizations of green sea turtles (Chelonia mydas) off the Caribbean island of Martinique, and identified which sounds seemed to be linked to flight, fear, and social aspects. When these recordings of sea turtles were played to wild sea turtles, they demonstrated behavioral responses (vigilance and/or escape) to the sounds they produce, suggesting that acoustic deterrents may be effective to reduce sea turtle bycatch. Sea turtles did not respond to synthetic or geophonic noises.

By modeling (GLMs and GAMs) data from onboard observers and logbooks, the authors investigated patterns in loggerhead sea turtle (Caretta caretta) bycatch in bottom trawlers in the Southern Adriatic Sea. Results indicate that most bycatch occurs during the daytime and in shallower coastal waters, and that it increases temporally in summer and autumn. The study also identified two bycatch hotspots: the Gargano promontory and off the coast of Brindisi.

Turtle excluder device (TEDs) with reduced bar spacing may help to reduce bycatch of small sea turtles that can pass through the deflector bars of standard TEDs. A bent bar top opening TED installed at 55°, a bent bar, bottom opening TED installed at 45°, and straight bar, top opening TED installed at 55° were evaluated. None of the TEDs significantly reduced total catch or bycatch. However, the bent bar, bottom opening TED and straight bar, top opening TED both significantly reduced invertebrate (largely jellyfish) catch.