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Sharks, turtles, billfish, and marine mammals are frequently caught accidentally in commercial fisheries. Although conservationists and fisheries managers encourage the release of these nontarget species, the long-term outcome of released animals is uncertain. Using blue sharks (Prionace glauca), we developed a model to predict the long-term survival of released animals based on analysis of small blood samples. About 5% of the sharks were landed in obviously poor condition (lethargic and unresponsive to handling); these moribund sharks were sampled and euthanized.

Seabird bycatch in the tuna and billfish longline fishery in South African waters has had one of the highest seabird bycatch rates in the world. Research was carried out aboard two Japanese longline vessels in the South African EEZ in 2010. Half of the branch lines on each vessel were weighted using the double-weight configuration, which consists of a weighted section that was inserted into the monofilament section of a branch line 2m above the hook. Each vessel also deployed two "hybrid" bird-scaring lines during every set. the lines had a mix of long and short streamers.

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 demonstrated a correlation between avoidance speed and distance with water temperature. 

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.

Two porpoises were subjected to 3 different underwater sounds (standard Dukane alarm, random Dukane alarm, and a "bird alarm") in a enclosed floating pen. Their behavior during a 15 min test period was compared to behavior during a baseline 15 min period before the test and a recovery period after the test. All alarms resulted in increases in both the distance of the animals' surfacings from the alarms and their respiration rates. The standard Dukane alarm and the bird alarm were more effective than the random alarm in inducing animals to swim away from the source. 

Two captive harbor porpoises were exposed to three sound types (frequency from 100 kHz to 140 kHz, 200 ms long, and presented once per 4 s). Each session consisted of a 10 min period persound, a 5 min period of sound, and a 10 min period after the sound. Behavior was recorded on video and with dataloggers. Animals reacted most to the intial presentations of sound, but the reactinos diminished rapidly in repeated sessions. 

A field test was conducted to test whether harbor porpoises habitutate to pingers over time. Echolocation and movements were monitored around a mooring equipped with a pinger (Dukane Netmark 1000) for 3 months. Initial displacement was 208 m from the pinger, but it diminished by 50% within 4 days. Echolocation rate and occurrence were significantly reduced near the pinger. 

The Hawaii longline swordfish fishery reduced seabird captures through mitigating bycatch during setting. Now, 75% of bycatch occurs during hauling. Observer data was fit to a generalized additive regression model and found that density of albatrosses during hauling, leader length, and year had the largest model effects. Heavier swivels, greater than 65g, had significantly fewer catch rates for seabirds. However, heavier weights with longer leaders had reduced effects.

An acoustic deterrent device (ADD) was tested at a Scottish salmon double bagnet to deter seals (grey and harbor). The ADD was randomly assigned to be on or off during observations, which were carried out from shore. When the ADD was on, there were significantly fewer seals observed and 1/3 more fish were landed per hour than when the ADD was off. Seal damaged fish were only found when the ADD was off.   

Trials of acoustic deterrent devices (ADD) were carried out on the River North Esk and River Conon in Scotland to test the effectiveness of deterring seals from a specific area of the river and as a barrier to upstream movement of the seals. The ADD was switched on and off alternatively for periods of several days and surveys were carried out to estimate the number of seals present within each river. The ADD had no significant effect on the abundance of seals in the survey area, but it did reduce seal movement upstream significantly.

Use-intensity distributions for 135 satellite-tracked adult leatherback turtles were combined with longline fishing effort to estimate predicted bycatch risk over space and time in the Pacific Ocean. For western Pacific nesting populations, the greatest risk was adjacent to primary nesting beaches in the tropical seas of Indo-Pacific islands. For eastern Pacific nesting populations, the greatest risk was in the South Pacific Gyre. Targeted management should be based on these predicted hotspots to reduce leatherback bycatch.  

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 to animal curiosity, high speed swimming, and calve protection.

Cory's shearwater, Calonectris diomedea, is the main seabird species incidentally caught by the Spanish longline fleet in the western Mediterranean Sea. The authors used onboard observer data to model the longline bycatch of Cory's shearwaters as a function of time of the year, technical characteristics of the fishing operation, and geographical location. The most explanatory factor for bycatch was the geographical location and then the technical characteristics (number of hooks and fishing during non-working days).

This study examined the spatial and temporal variations in bycatch rates of four species of great albatrosses. Observer data was obtained from the Uruguayan pelagic longline fleet and Japanese vessles operating in Uruguay. Vessel operational practices and habitat variables affected bycatch rates, including: setting time, moon phase, and area and season. 

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 gear-species interactions were also identified, such as humpback whales and pots/traps.  

The long-term effectiveness of acoustic pingers in reducing marine mammal bycatch was assessed in the California swordfish and thresher shark drift gillnet fishery. Bycatch was observed at sea between 1990 and 2009, with acoustic pingers being present from 1996 to 2009. Bycatch rates of cetaceans decreased by around 50% when pingers were present; the decrease was mostly driven by common dolphins. Beaked whales have not been incidentally caught since 1995. Pinger failure occurred in less than 4% of observed sets.

This study reviews existing data and information from key stakeholders on interactions between the fishing industry and seals. The data suggests that seal interactions with commercial fisheries in Ireland are most significant inshore (<12 nautical miles from shore), involves static-net (passive) fisheries (e.g. gill/tangle nets) and have increased following the driftnet ban in 2006, suggesting displacement of seal interaction from salmon to other fisheries.

Incidental captures of the franciscana dolphin (Pontoporia blainvillei) by artisinal coastal fishermen of Buenos Aires, Argentina were investigated. Data was collected on carcasses of 54 incidentally captured dolphins between 2003 and 2009. Results indicated that the majority (69%) were animals four years old and younger, 74% of entangled animals were sexually immature and 85% were physically immature. Entanglements were not associated with any disease or physiological disorder. No bycatch mitigation techniques were tested for this paper.

Information on the use of Dolphin Wall Nets (DWN) by fisherman in Kerala, India was presented in this paper.  The DWN was designed by these fishermen to reduce dolphin attacks during fishing operations. Specifically humpbacked dolphins tend to congregate in fishing areas, surrounding the ring seine net and removing fish from the net.  This net design can be used by fishermen instead of crackers, which can cause harm to the dolphins. The authors provided fishermen from four stations in Kerala, India (Kasargode, Kozhikode, Ernakulum and Kollam) questionnaires to fill out.

Field experiments were conducted to determine behavioral responses of minke whales to experimental ropes and buoys made up of different colors, simulating those used in crab and whelk fishing gear. Trials were conducted with yellow, orange, green, blue, white and black ropes. Visual and acoustic monitoring was used to assess behavioral responses of whales to the different experimental gears. In addition, remote sensing equipment was used to monitor oceanographic conditions, underwater sounds and to video the whales as they swam near the experimental ropes.