This study provides a summary of methods that can be used to reduce depredation and bycatch of marine mammals in longline fisheries. Methods include 1) spatial management methods, 2) acoustic methods, 3) physical methods and 4) ‘other methods’. The results indicate that some methods can be used with both pelagic and demersal longlines, while others […]
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Behavioral responses of bottlenose dolphins, Tursiops truncatus, to gillnets and acoustic alarms | Consortium for Wildlife Bycatch Reduction
The authors tested the behavioural response of bottlenose dolphins (Tursiops truncatus) to gill nets equipped with active and control Dukane NetMark 1000 pingers. Although dolphins were observed significantly fewer times within a 100m circular buffer zone from the alarms, overall results showed no significant differences in the number of groups observed, or closest approaches by […]
A risk-based approach to rapidly screen vulnerability of cetaceans to impacts from fisheries bycatch | Consortium for Wildlife Bycatch Reduction
Potential risk of fisheries to cetaceans was assessed using a screening procedure based on a Productivity Susceptibility Analysis (PSA) using gears found in Ireland. Gillnets targeting demersal species was assessed as the fishery posing the greatest risk to cetaceans. Pelagic trawls targeting small pelagic species was found to pose a moderate risk to cetaceans. Specific […]
Post-release survival, vertical movements and thermal niche partitioning in five species pelagic sharks released from longline fishing gear in the central Pacific Ocean | Consortium for Wildlife Bycatch Reduction
From 2001 to 2006, 71 pop-up satellite archival tags (PSATs) were deployed on five species of pelagic shark (blue shark [Prionace glauca]; shortfin mako [Isurus oxyrinchus]; silky shark [Carcharhinus falciformis]; oceanic whitetip shark [C. longimanus]; and bigeye thresher [Alopias superciliosus]) in the central Pacific Ocean to determine species-specific movement patterns and survival rates after release […]
Health of North Atlantic right whales Eubalaena glacialis over three decades: from individual health to demographic and population health trends | Consortium for Wildlife Bycatch Reduction
Photographic data on body and skin condition, blowhole cyamids and rake marks were used to evaluate the health of North Atlantic right whales (Eubalaena glacialis) from 1980-2008. A hierarchical Bayesian model was applied to the data to estimate demographic groups, underlying health status conditions and the population to characterize health patterns and temporal trends. Visual […]
Hector's dolphin risk assessments: old and new analyses show consistent results | Consortium for Wildlife Bycatch Reduction
Information on bycatch of Hector’s dolphins in New Zealand waters was reviewed and new estimates were presented. Prior to 2008, 110-150 Hector’s dolphins were estimated to be caught annually. Of these, 35-46 were caught of the east coast South Island. Between May 2009 and April 2010, an estimated 23 Hector’s dolphins were caught of the […]
Interaction between bottlenose dolphin (Tursiops truncatus) and trammel nets in the Archipelago de La Maddalena, Italy | Consortium for Wildlife Bycatch Reduction
A study was conducted in the waters off the coast of Archipelago de La Maddalena (Italy) to determine the impact bottlenose dolphins had on gillnet fisheries targeting a variety of fish species. The study showed that the catch per unit effort of target species was significantly higher when there were no dolphin interactions. There were […]
Review and evaluation of three mitigation measures-bird-scaring line, underwater setting and line shooter-to reduce seabird bycatch in the north Atlantic longline fishery | Consortium for Wildlife Bycatch Reduction
Bird-scaring lines, underwater setting and line shooters all reduced the incidental capture of seabirds, with bird-scaring lines being the most effective. These mitigation measures also reduced bait loss and increased the catch rates of target species.
The effects of neodymium-iron-boron permanent magnets on the behavior of the small spotted catshark (Scyliorhinus canicula) and the thornback skate (Raja clavata) | Consortium for Wildlife Bycatch Reduction
Neodymium-iron-boron (Nd2Fe14B) permanent magnets were used to test behavioral responses in spotted catsharks (Scyliorhinus canicula) and thornback skates (Raja clavata). Both species significantly avoided the Nd2Fe14B magnets more often in comparison to the control and procedural control and they fed significantly more from the control an procedural control in comparison to the magnets. The study also […]
Effects of bycatch on the population viability of the narrow-ridged finless porpoises in Ariake Sound and Tachibana Bay, Japan | Consortium for Wildlife Bycatch Reduction
A Leslie Matrix model was used to simulate the impact of bycatch mortality on the narrow-ridged finless porpoise (Neophocaena asiaeorientalis). Based on the model results, there is an annual rate of decrease of 0.671 to 3.87%, with a population reduction of 29.6 to 86.3% over three generations. The most optimistic simulation showed at least a […]
Cetacean-fishery interactions in Galicia (NW Spain): results and management implications of a face-to-face interview survey of local fishers | Consortium for Wildlife Bycatch Reduction
A survey was conducted with fishers in Galicia Spain to investigate interactions between fishing gear and cetaceans. Cetacean fishery interactions appear to be frequent events. Although the damage to the catch and fishing gear were generally reported to be small, substantial economic loss can result from interactions with common bottlenose dolphin (Tursiops truncatus) and coastal […]
Stress, post-release mortality, and recovery of commonly discarded deep-sea sharks caught on longlines | Consortium for Wildlife Bycatch Reduction
Bycatch interactions with deep-sea elasmobranchs are increasingly common and can lead to dramatic declines in abundance over short time scales. Sharks hooked in the deep sea could face a higher likelihood of severe physiological disturbance, at-vessel mortality, and post-release mortality (PRM) than their shallower counterparts. Unfortunately, robust PRM rates have not yet been estimated for […]
Compose tips | Consortium for Wildlife Bycatch Reduction
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Comparison of circle hooks and J hooks in the catch rate of target and bycatch species taken in the Korean tuna longline fishery | Consortium for Wildlife Bycatch Reduction
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 […]