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The Patagonian toothfish (Dissostichus eleginoides) longline fishery has high levels of depredation by killer and sperm whales (Orcinus orca;Physeter macrocephalus) , which puts the whales at risk of becoming bycatch. Observations from 2003 to 2008 revealed significant variations of interaction rates with killer whales between vessels, suggesting the influence of operational factors on vessel interaction and depredation. When killer whales were absent at the beginning of the line hauling process, short lines (<5,000 m) provided higher yield and were significantly less impacted by depredation than longer lines. The authors also recommend that when facing depredation, vessels should leave the fishing area and travel distances > 40 n miles to prevent killer whales from finding them within a few hours. 

A double-fish aggregating device (FAD) design was tested for its ability to mitigate the incidental capture of juvenile bigeye tuna (Thunnus obesus) in purse seine fisheries in the Western and Central Pacific Ocean. The design consisted of two separate FADs with underwater light stimuli attached. The number of animals caught was not large enough to conduct statistical analyses, but based on the weight of fish, the size proportion of skipjack (Katsuwonus pelamis), yellowfin (Thunnus albacares), and bigeye was bigger using the Double-FAD design compared to the standard design. The bycatch rate (proportion of total catch) of bigeye tuna was 6.1% and 7.2% using Double-FADs and 8.9% and 14.2% using standard FADs for numbers and weight respectively.  The proportion of skipjack tuna caught using the Double-FADs was 58.6% (number) and 29.1% (weight) compared to 72.4% (number) and 39% (weight) with the standard FAD.  The proportion of yellowfin tuna using the Double-FADs was 35.4% (number) and 63.7% (weight), while with the standard FAD, the proportion was 18.7% (number) and 46.8% (weight).  It appears this design has some effect on reducing bigeye tuna bycatch, despite the low sample size.

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.

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.

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.

A study was conduceted to test the effect of SaveWave acoustic deterrent devices on target fish catch and bottlenose dolphins (Tursiops trunactus) in the North Carolina Spanish mackerel (Scomberomorus maculatus) gillnet fishery in the United States. 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 with gillnets. The SaveWave device did not affect fish catch. Dolphins were less likely to interact with gillnets and more likely to echolocate when SaveWaves were present. However, SaveWave devices were not sufficiently durable to be deployed in this fishery.

Gear modifications to the Loligo squid trawl net were developed to reduce scup (Stenotomus chrysops) bycatch. Two extension modifications, vee and ring excluders, were developed to aid in reducing scup bycatch when large schools are encountered.  These extensions were based on the grid/gate design but made flexible enough to be wound up. The extensions work as an obstruction device and are flanked by fisheyes, which allow the fish to escape.  Previous trawl net modifications were unable to reduce scup bycatch when large schools entered the gear.  The two extensions were able to remove scup at mean rates of 86-100% compared to standard trawl gear, although small (<10 cm FL) scup were not excluded.  There were no real differences in removal rates between the two extensions.  However, the vee excluder did also remove more squid (53-69%) from the net compared to the ring excluder (7-58%).   

Experiments were conducted aboard pelagic longline vessels in the western North Pacific to determine the effectiveness of paired tori lines in reducing seabird bycatch.  Paired tori lines (PT) were compared against single tori lines (ST) during these tests.  The most abundant species of bird attacking longlines was the Laysan albatross (Phoebastria immutabilis) (90.2%).  There was a significant difference in the mean number of albatross and shearwater between ST and PT deployments, with the mean number of birds being lower with PT deployments.  PT deployments reduced attacks by albatross by 47.8% and few attacks occurred within 75 m of the stern.  However when ST were deployed, albatross attacked from 25 to 200 m of the stern.  The number of secondary attacks was significantly lower when PT were used compared to ST, with PT deployments reducing secondary attacks by 43.4%.  In addition, no statistically significant difference in the distribution of secondary attacks between port and stern were found when ST were used but statistical differences were found during PT deployments.

Experiments were conducted at sea to determine the ability of a "topless" shrimp trawl to reduce bycatch of Atlantic herring (Clupea harengus). The "topless" effect was created by removing the square and the top part of the section after the square on the trawl.  At-sea trials resulted in a reduction of Atlantic herring bycatch by an average of 86.6% and produced an increase of 13.5% in pink shrimp (Pandalus borealis) catch. The bycatch of several species of flounder did increase with this new design, albeit less than 3%, which could have been a factor of the wider wingend spread and slight difference in the footgear between the experimental and traditional gear.  There were no differences in catches for other bycatch species (blueback herring (Alosa aestivalis) and silver hake (Merluccius bilinearis)) between the two gears. In addition, the "topless" trawl was easier to sort and clean and therefore required less labor.