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Experiments were conducted aboard pelagic longline vessels in the western North Pacific to determine the effectivness 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 (90.2%).  There was a significant difference in the mean number of albatross and shearwater birds between ST and PT deployments, with the mean number of birds being lower with PT deployments.

Experiments were conducted at sea to determine the ability of a "topless" shrimp trawl to reduce bycatch of Atlantic herring.  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 catch.

Two types of longline sets, night and day, were evaluated for differences in catch composition in Seychelles waters.  Night sets were set at dusk and retrieved at dawn and used shallow baskets targeting swordfish, while day sets were set at dawn and retrieved at dusk and used shallow and deep baskets to target tuna.  The majority (75%) of species, both bycatch and market, were caught during day sets. The proportion of bycatch to target species decreased with depth.

Experiments were carried out aboard vessels in the Danish North Sea hake gillnet fishery to determine if increasing the spacing of Aqutec AQUAmark100 pingers could be done without negatively impacting the effectiveness of the pinger. Control nets without pingers were tested alongside nets with pingers spaced at 455 m and 585 m. The control nets had a bycatch frequency of 0.54 incidents/haul for harbour porpoises. Nets with pingers spaced at 455 m had an incidence rate of 0 and nets with pingers spaced at 585 m had a bycatch frequency rate of 0.12.

Blue sharks account for most of the bycatch in the Canadian pelagic longline swordfish fishery. Electropositive metals (e.g. lanthanide) oxidize in seawater and create electric fields, which can alter the behaviors of several species of sharks. Researchers deployed seven sets (6300 hooks) with three hook treatments (standard hooks, hooks with electropositive metals - neodymium/praseodymium - and hooks with lead weights) on the Scotian Shelf in the Northwest Atlantic. Electropositive metals did not reduce the catch of blue sharks or other common shark bycatch species.  

This paper is a global assessment of marine mammal (cetacean, pinniped, sirenian, and marine mustelids) bycatch in gillnets and other entangling nets from 1990 to 2011. The authors found that at least 75% of odontocete species, 64% of mysticetes, 66% of pinnipeds, and all sirenian and marine mustelids have been recorded as gillnet bycatch over the past 20 years. 

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 in the Northwest Pacific, Iceland, and the Baltic Sea.  

Studies were conducted aboard beam trawlers in the North Sea to determine the performance of pulse beam compared to conventional tickler chain beam trawlers.  Overall the pulse beam trawl caught 68% less than the conventional trawls.  Specifically, the pulse beam trawl caught significantly fewer plaice and sole compared to the conventional beam trawl. There was no significant difference in catch rates of undersized plaice between the two gears but the pulse beam trawl caught significantly less undersized sole.

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 the alarms were used but the likelihood of them leaving the area was not significantly different from the control.  This suggests this type of acoustic alarm may not be useful as a bycatch mitigation measure for these species.

Experimental trials were carried out in Argentina comparing franciscana bycatch rates in standard gillnets with gillnets with increased acoustic reglectivity by infusion with barium sulphate (BaSO4) and increased flexural stiffness of the nylon twine. There was no significant difference in franciscana bycatch rates or target catch rates among the three net types.  

Several seabird bycatch mitigation techniques were tested aboard distant water tuna fisheries in the South African EEZ.  Two types of bird scaring designs, light lines with short streams vs. hybrid lines with a mix of streamer lengths were compared with unweighted branch lines. In addition, unweighted to weighted branch lines were tested and night vs. day setting with a combination of bird scaring lines were tested for their effects on seabird avoidance and targeted fish catch rates.

Tests with lanthanide metals were conducted to determine their potential application as a shark repellent in longline fisheries.  Six lanthanide metals were tested (cerium (Ce), neodymium (Nd), praseodymium (Pr), cerium-lanthanum mischmetal (CeLa), praseodymium neodymium metal alloy (PrNdA) and praseodymium neodymium mischmetal (PrNdM)) to quantify their voltage and compare dissolution rates in seawater. A behavioral study was used to determine their efficacy in deterring bonnethead and lemon sharks.

Two experiments were conducted to determine if 1) UV illumination reduced green sea turtle capture rates in large mesh gilllnets and 2) what was the impact of UV illumination on target catch rates in bottom-set gillnets.  Paired tests were conducted using a control net and an experimental net with UV LEDs placed every 5 m on the floatlines for the sea turtle experiment.  In the target catch experiment, inactive LEDs were also placed on the control net at 5 m spacing's.

This paper presents a review of studies on gear technologies used to improve species and size selection in Nephrops trawl fisheries in the North Sea, Irish Sea, Kattegat and Skaggerak.  The following categories of gear modifications were analyzed: separator grids, separator/guiding panels, square-mesh panels, capture avoidance designs, and codend modifications.  The best gear design depends on the management objectives of the fishery.

At sea trials were conducted comparing the catch composition and weight of standard Nephrops scraper trawls and a new trawl termed the Flip Flap netting Grid trawl (FFG).  The FFG includes a 160 mm mesh size netting in the top wing and top sheet netting panels, flip-flap netting grid, and fish outlet hole and 200 mm square mesh panel fitter in front of the fish outlet hole. The FFG trawl resulted in a ~30% reduction (number) of small cod around 32 cm in length but not in fish smaller than this.

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 number of hooks.

Acoustic pingers (Dukane Netmark 1000; frequency of 10-12 kHz and emit 300 ms tone every 4 sec with a source level range of 120-146 dB) were assessed to determine the effectiveness for reducing bycatch of dolphins and porpoises (common dolphins, dusky dolphins, bottlenose dolphins, Burmeister's porpoise, and pilot whales) by Peruvian small-scale driftnet fleets. Pingers were tested between April 2009 and August 2011. Twenty-two percent of the control nets captured small cetaceans and 16% of experimental nets captured small cetaceans.

Shrimp is one of the most valuable fishery resources of Venezuela, with landings about 12 400 t (2007) and worth more than US $35 million. Fishing is carried out along the coast; the industrial trawl fleet used to operate at depths between 10 and 120 m, while fishing with artisanal gears is done close to shore, in coastal lagoons, gulfs and in Lake Maracaibo at depths from 1 to 40 m. The latter represent 84% of landings, mainly from Lake Maracaibo. While only the shrimp is sold by the artisanal fleet, the industrial fleet also sells some fish species, crabs and mollusks.

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 from longline fishing gear.

Campana et al. (2009; Mar Ecol Prog Ser 387:241–253) explored the survival of blue sharks (Prionace glauca) captured and released from the North Atlantic commercial longline fishery. We think that their comments and comparisons do not accurately reflect a previous survival study of blue sharks in Hawaii (Moyes et al. 2006; Trans Am Fish Soc 135:1389–1397). The differences in mortality between the studies, ~5% in the Hawaii-based fishery and ~35% in the North Atlantic fishery,