Experiments were conducted aboard Korean pelagic longline vessels to determine if there were differences in the catch rates of target (tuna and billfish) and bycatch (sharks and other bony fish) species between 3 types of hooks; 4.0 traditional tuna hook (J-4), size 15 circle hook (C15) and size 18 circle hook (C18). Within the target […]
September 2023
The incidental catch of seabirds in gillnet fisheries: A global review | Consortium for Wildlife Bycatch Reduction
This paper is a global review of seabird bycatch in gillnets. The authors identified 148 seabird species as susceptible to bycatch in gillnets, of which 81 have been recorded incidentally caught. A review of reported bycatch estimates suggests that at least 400,000 birds die in gillnets each year. The highest levels of bycatch are reported […]
Acoustic alarms elicit only subtle responses in the behavior of tropical coastal dolphins in Queensland, Australia | Consortium for Wildlife Bycatch Reduction
Fumunda acoustic alarms were tested in the absence of nets to determine their ability to modify the behavior of Australian snubfin and humpback dolphins, with possible applications to gillnet fisheries. The alarms emitted a regular interval pulse of 300 ms every 4 seconds at 10 kHz frequency. The behavior of the animals changed slightly when […]
Bycatch mitigation assessment for sharks caught in coastal anchored gillnets | Consortium for Wildlife Bycatch Reduction
The potential of modifying gillnets to reduce shark bycatch was investigated in the US Spanish mackerel and spot gillnet fisheries. The modified net had larger floats on the head-rope and inreased weight on the lead-line to increase the tension of the net. Results showed that the catch rate of some shark species was significantly reduced […]
State-space mark-recapture estimates reveal a recent decline in abundance of North Atlantic right whales | Consortium for Wildlife Bycatch Reduction
A state-space model, using the Jolly-Seber assumption about population entry, was used to characterize the changing abundance of North Atlantic right whales (Eubalaena glacialis) between 1990 and 2015. Estimates from this modeling approach were only slightly higher than published values, except for the most recent years (capture rates substantially declined). North Atlantic right whale abundance […]
Effects of pingers on the behaviour of bottlenose dolphins | Consortium for Wildlife Bycatch Reduction
Trials to assess the behavioural response of free-ranging bottlenose dolphins to continuous and responsive pingers were conducted. In boat based trials both types of pinger affected dolphin behaviour, while in static trials the detection of dolphin vocalisations was significantly lower in the presence of active continuous pingers.
Acoustic characterization of bycatch mitigation pingers on shark control nets in Queensland, Australia | Consortium for Wildlife Bycatch Reduction
Acoustic pingers, Fumunda F3 (2.7 kHz) for humpback whales and F10 (10 kHz) for dolphins, were used on sharks nets within the Queensland Shark Control Program. Sound from the acoustic pingers was present for around 1.5 km beyond the nets. Humpback whales and dugons were able to hear the F3 pinger 90 m from the […]
Trade-offs in the Design of Fishery Closures: Management of Silky Shark Bycatch in the Eastern Pacific Ocean Tuna Fishery | Consortium for Wildlife Bycatch Reduction
Bycatch—the incidental catch of nontarget species—is a principal concern in marine conservation and fisheries management. In the eastern Pacific Ocean tuna fishery, a large fraction of nonmammal bycatch is captured by purse-seine gear when nets are deployed around floating objects. We examined the spatial distribution of a dominant species in this fishery’s bycatch, the apex […]
A field experiment using acoustic alarms (pingers) to reduce harbour porpoise by-catch in bottom-set gillnets | Consortium for Wildlife Bycatch Reduction
Pingers were tested to reduce harbour porpoise (Phocoena phocoena) bycatch in bottom-set gillnets in the Swedish Skagerrak Sea. During the experiment, no harbour porpoise were caught in control or experimental gillnets, possibly as a result of a combination of factors including displacement of porpoise, high prey availability in other areas, or pingers acting as passive […]
Extension trial of an acoustic deterrent system to minimize dolphin and porpoise bycatch in gill and tangle net fisheries | Consortium for Wildlife Bycatch Reduction
Fisheries observers and skippers tested the effectiveness of the Dolphin Dissuasive Device (DDD) as a bycatch mitigation tool for porpoises and dolphins. This study was conducted aboard fishing vessels in the Cornish over-12m static net sector fishery in the waters of Southwest England. DDD’s were placed at the end nets. The DDD’s caught significantly fewer […]
Accidents between artisanal fisheries and cetaceans on the Brazilian coast and Central Amazon: proposals for integrated management | Consortium for Wildlife Bycatch Reduction
This study qualitatively describes accidents between cetaceans and fishing boats on the Brazilian coast and the Central Amazon region through the perception of artisanal fishers. From 2005 to 2010, 215 interviews were conducted. Fishers identified encounters with five species: Inia geoffrensis, Sotalia guianensis, Tursiops truncatus, Eubalaena australis, and Megaptera novaeangliae. They said accidents occurred due […]
A field test of acoustic deterrent devices used to reduce interactions between bottlenose dolphins and a coastal gillnet fishery | Consortium for Wildlife Bycatch Reduction
A study was conduceted to test the effect of SaveWave acoustic deterrent devices on target fish catch and bottlenose dolphins in the North Carolina Spanish mackerel gillnet fishery. Observations were carried out on commercial vessels and focal visual and acoustic follows of dolphins were conducted. Fish catches were significantly lower when dolphins were observed interacting […]
Impact of Costa Rican longline fishery on its bycatch of sharks, stingrays, bony fish and olive ridley turtles (Lepidochelys olivacea) | Consortium for Wildlife Bycatch Reduction
An observer program assessed the impact of the Costa Rican longline fishery on bycatch species from 1999 to 2010. Observers recorded species, sex, reproductive state, and dimensions of all animals captured. They also recorded information about individual longlines, including location, set and haul back times, hook type, hook number, bait used, target species, and total […]
The effects of a lanthanide metal alloy on shark catch rates | Consortium for Wildlife Bycatch Reduction
Longlines with baited hooks affixed with a block of metal alloy (Nd/Pr) were tested against hooks with a lead weight attached (control), to determine their ability to repel sharks. Two experiments were conducted in Hawaiian waters, one in the Southern California Bight (SCB) and and one in the Eastern Tropical Pacific off the coast of […]
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