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Five biodegrabable twine types were investigated for potential use in the snow crab (Chinoecetes opilio) fishery that operates off Newfoundland and Labrador, Canada. The five twine types included 1) 2-ply Sisal, 2) 3-ply Cotton 60-threated, 3) 3-ply Cotton 72-thread, 4) 3-ply Cotton 96-thread and 5) 3-ply Hemp 40 strand. Each twine was deployed at sea for 124 days and their degradation rates over time were studied. The results indicate variability in twine degradation rates. The 3-ply cotton 96-thread twine was the best performing twine.

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 is a comprehensive, critical overview of studies on the use of electrotrawling in the North Sea. Electrotrawling, involves replacing the tickler chains or bobbins with electrical stimulation. The result is reduced contact with bottom habitats, reduced fuel costs and reduced discards. An overview on the current status and implementation of this technique in flatfish, shrimp and razor clam fisheries is provided. In terms of the flatfish fisheries, while electrotrawling is a promising alternative, potential negative impacts (i.e.

Experimental studies were conducted over a three year period (August 2008-December 2011) to determine the effects of changing traditional J-hooks baited with squid bait to circle hooks (offset and non offset) with mackerel bait on sea turtle interactions. Studies were carried out aboard pelagic longline vessels targeting swordfish in the tropical northeast Atlantic Ocean. Overall, sea turtle interactions were reduced when circle, compared to J-hooks were used. However species specific differences did occur.

A population viability analysis and evaluations of bycatch mitigation techniques were used to investigate the impact of bycatch mortality on the populations of four freshwater turtles (common snapper, Chelydra serpentina, eastern musk, Sternotherus odoratus, northern map, Graptemys geographica, and painted, Chrysemys picta) incidentally captured in small-scale commercial fisheries operating in Lake Opinicon, Ontario, Canada.  Two approaches to bycatch reduction were investigated.

The authors conducted an extensive literature review to determine if Sea Lion Excluder Devices (SLEDs) allow sea lions to escape from trawl nets and if they subsequently survived. In addtion, the literature was reviewed to determine if head trauma was likely when sea lions come into contact with stainless steel SLED grids. According to the literature, SLEDs are effective in reducing sea lion bycatch in trawl nets and resulted in a reduction of observed sea lion mortalities.

A study was conducted to determine the impact of removing the 'tickler' from in front of groundgear of trawls. The 'tickler' is a length of chain placed in front of the groundgear of trawl gear, which is supposed to increase catches of sharks and rays. Tests were conducted where the 'tickler' was removed and secondary nets (groundgear bags) were placed behind the groundgear to determine the amount and species of fish that escaped capture. The results indicated that removing the 'tickler' from in front of the groundgear reduced the capture of skates and sharks.

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

The authors investigated the effects of a large-scale gillnet closure on sea bird populations in Canadian waters. After a 1992 closure, breeding populations of bycatch-prone diving birds (auks and gannets) increased, with a corresponding decrease in surface-feeding scavengers such as gulls that are less prone to bycatch in gillnets but that do consume fisheries discards.

Trials were conducted using excluder grids on trawls targeting Norway lobster (Nephrops novegicus) and greater forkbeard (Phycis blennoides) in the Tyrrhenian Sea. The excluder grids were tested for their ability to reduce the incidental capture of blackmouth catshark (Galeus melastomus).  In order to estimate the number of escaped fish, covers were placed over the escape outlet before the grid and over the codend. The 90 mm excluder grid did not result in reduced catches of blacknouth catshark.

Pelagic longline hooks equipped with magnets were tested for their ability to repel blue sharks.  Tests were conducted aboard pelagic longliners operating in the Northeast Atlantic Ocean. Two magnets, one large and one small, were tested. Magnets were manually attached to the hooks (polarized so the magnet field was oriented N or S and in parallel with the hook axis). Three test zones, each with 5 hooks with 1 magnet, 11 hooks with 2 magnets and 16 control hooks, were deployed along a longline.

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. 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.

The authors conducted a review of post release mortality studies on billfish caught in recreational fisheries.

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 30% reduction in population size. Therefore, reported bycatch mortality rates pose a substantial threat to this species.

Experiments were conducted along the Swedish coast to investigate the impact of seal exclusion devices (SEDs) on seal bycatch. Pot entrances were fitted with SEDs of different shapes and sizes. The pots were a two-chambered single entrance floating cod pot. Pots were equipped with a 45 mm escape window. Experimental pots had vertically mounted metal frames that were secured with nylon line. Five different types of SEDs were used. They had different metal frames, different shapes, thickness of material or inner circumference.

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 also differences in the species composition of nets attacked and not attacked by dolphins. Those nets attacked by dolphins showed a reduction in the catch of cuttlefish and red mullet while catches of scorpionfish increased.

A study was conducted on observed interactions between a Portuguese purse-seine fishery and cetaceans. Cetaceans, primarily common dolphins (Delphinus delphis), were present during 16.9% of fishing events. The majority of these occurrences happened during the summer and early fall, and during the night. The presence of cetaceans was significantly linked to sardine catches, effort and latitude/longitude. Encirclement of cetaceans occurred in 2.3% of fishing events, with moralities occurring in 1%.

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 gillnet fishing gear, and from short-beaked common dolphins (Delphinus delphis) interactions with purse seine fisheries.

Three types of bycatch reduction devices (BRD) [turtle excluder device (TED), square mesh codend (SMC) and fisheye (FE)] were tested aboard shrimp trawl vessels. Differences in catch from nets equipped with a BRD on one side and a standard net on the other were compared for each of the three BRD's. Use of the TED resulted in no captures of sea turtles or large animals, and did not significantly reduce shrimp catches or fish bycatch.

A study was conducted aboard vessels from the South Australian Spencer Gulf prawn fishery to examine the utility of a mechanical-separating bycatch reduction device. The fishery targets prawns but has bycatch of giant cuttlefish (Sepia apama) and blue swimmer crabs (Portunus armatus). Conventional codends were tested against small and large Nordmore-grids set at high and low grid angles. Both grids resulted in bycatch reductions. The number and weight of cuttlefish were reduced by 50.4% and 59.7%, respectively, when the small grid was used.