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Pingers have been used on shark nets set along Queensland's beaches since 1992. Due to an increase in whale entanglements in 2009, new pingers (Fumunda F3 whale pingers and F10 dolphin pingers) were deployed between July and August 2010. Subsequently updated research on the use of these pingers was needed. For this study, the acoustic characteristics of pingers used on shark nets in Queensland Australia were measured and used to model sound propagation, estimate over what range marine mammals could detect the pingers, monitor ambient noise and to make recommendations on pinger deployment to the Queensland Shark Control Program (QSCP). The results of the sound propagation study indicate that the tones were a few hundred Hz less (2.6-2.8 Hz for F3 and 9.4-9.6 Hz for F10) than indicated. All pingers emitted multiple harmonics and fundamental tones. The power spectrum density levels varied up to 20 dB from angle to angle and pinger to pinger. The 1st harmonic of F3s was audible to all marine mammals over the longest ranges. Only 2 of the 6 tested pingers reached the manufacturer's listed audible range of 1-5 km. During testing, the ranges depended on the individual pinger and angle of the pinger toward the mammal. When animals travel alongside the net, a number of pingers should be set in a series. Based on the current configuration of 3-4 pingers per net of 200 m, humpback whales (Megaptera novaeangliae) would hear all of the pingers at any location along the net but dolphins would hear only 1-2 pingers. When animals swim straight at the net, maximum pinger spacing would need to be based on the animals swim speed. The current net/pinger configuration is adequate for humpback whales, dugongs (Dugong dugon) and dolphins swimming at normal travelling speeds. The current pinger spacing is insufficient for dolphins swimming straight at the net at high speeds.

This study qualitatively describes collisions 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. The authors propose co-management with local members, researchers, and the government to encourage feelings of collective ownership within communities aiming to minimize the number of collisions. 

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 (Megaptera novaeangliae) and pots/traps.  

Entanglements of large cetaceans in fishing gear that occurred off the coast of Peru between 1992 and 2012 were catalogued. Direct observations, local news and online graphical evidence was used to identify any entanglements. A total of 15 confirmed entanglements were identified. The species involved in these entanglements included humpback whales (Megaptera novaeangliae), sperm whales (Physeter macrocephalus) and Antarctic minke whale (Balaneoptera bonaerensis). The most common entanglements occurred in gillnets, followed by longlines. This study did not investigate the use of bycatch mitigation techniques.

Entanglements of large cetaceans in fishing gear that occurred off the coast of Peru between 1992 and 2012 were catalogued. Direct observations, local news and online graphical evidence was used to identify any entanglements. A total of 15 confirmed entanglements were identified. The species involved in these entanglements included humpback whales (Megaptera novaeangliae), sperm whales (Physeter macrocephalus) and Antarctic minke whale (Balaneoptera bonaerensis). The most common entanglements occurred in gillnets, followed by longlines. This study did not investigate the use of bycatch mitigation techniques.

This article reviewed bycatch mitigation methods that rely on sensory ecology to reduce interactions with seabirds, 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, except for cetaceans. Cetaceans require both visual cues and warning through echolocation.

Depredation by Antarctic fur seals (Arctocephalus gazella), sperm whales (Physeter macrocephalus) and orcas (Orcinus orca) were studied in a Patagonian toothfish (Dissostichus eleginoides) fishery operating around South Georgia Island. While sperm whales come in contact with about one third of longlines (averaged over 1997 and 2012), depredation events from this species were considered insignificant. Orcas interacted with only 5% (averaged over 1997 and 2012) of longlines, but can remove over half the catch during an interaction. Interactions with orcas are spatially limited to migration routes; however, fishing is concentrated in these areas during migrations times. Interactions with fur seals were the most frequent until 2009, averaging just under 9% from 1997-2012. The catch-per-unit-effort of toothfish was higher when no mammals were observed near longlines. 

Interactions between vertical lines under increased tension with a physical model of a North Atlantic right whale (Eubalaena glacialis) flipper was investigated. This was an updated experiment. The original flipper model was based on data (flipper outlines and bone measurements) collected from three different whales. The physical flipper was computer generated from these data and covered with 1/2 in neoprene rubber, which was overlayed with 1/8 in thick vinyl rubber sheeting. The flipper was made from fiberglass, was free flooding and covered with 1/2 in neoprene and then with 1/8 in vinyl-rubber. The flipper angle was adjustable forward and aft, relative to the 'whale body'. The flipper and frame was attached to a fishing boat, and deployed 12 feet below the surface. A taut vertical line was created using a large mooring block, which was fitted with a pulley and a swivel. A 5/8 in line was attached to a 28 in float and attached to a sinking line that ran across the bottom. Cameras were used to observe the flipper-line interactions. Scenarios were run using both forward and aft flipper positions, and at different contact points along the flipper's leading edge. There were three zones (relative to the whale body panel) on the leading edge: A) acute, N) normal and O) oblique. During the first 11 trials, six events were glancing interactions in zone C (outer edge) and five interactions occurred at zones A and B. The flipper moved vertically down, with a slight angle towards the back edge of the flipper, in the water column during these interactions. The second 11 trials occurred in zones A and B with one glancing event in zone C. The interactions (except for the glancing) resulted in the float moving downward. Interactions that occurred in zone A and B lead to significant damage to the leading edge of the flipper. The results from these trials suggest that for entanglements involving a whale flipper as the initial point of contact with vertical fishing ropes, increased line tension will likely produce more severe lacerations than ropes under lower tension. Any potential benefit of using ropes with increased tension may be offset by the potential for more severe injury.

This study investigated whether North Atlantic right whale (Eubalaena glacialis) behavior changes, in terms of response distance, to changing visual characteristics of rope mimics in their path. 20 ft rope mimics were made from two 10 ft sections of rigid PVC pipe, with an approximate diameter of 1 inch. The rope mimics were weighted and attached to a lobster buoy to simulate a vertical line in the water column. A 30.5 cm disk was placed around the rope for reference use in video footage. The following color ropes were used: black, green, two types of white (white and glow in the dark), orange and red. Experiments were conducted in Cape Cod Bay (United States) using surface feeding whales. A significant difference in the distance of first change in behavior occurred between black and green ropes vs red and orange ropes. The response time was earlier with the latter colors. No significant difference was found between frontlit and backlit ropes.

Low-powered sound sources were tested for their ability to deter gray whales (Eschrichtius robustus) from potentially harmful areas. An acoustic device (1-s frequency modulated 1-3 kHz warble deterrent signal) was moored to the seafloor in the gray whales migration path off central Oregon (United States). Observers (land based) tracked whales with a theodolite to locate whales as they passed the headland. Tracklines were compared between times when the acoustic deterrent was on and off. Statistical analysis did not show a significant difference between the hypothesized zone of influence (within 500 m of the deterrent) and areas out to 3 km. Poor weather and equipment issues prevented acquiring an adequate sample size, so the results were considered inconclusive.