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A literature review of 30 studies was conducted to determine the  effectiveness of various bycatch reduction devices for elasmobranchs. The risk of capture was 1.2 times higher on circle hooks but haulbaulk mortality as well as deep hooking was reduced. Wire leaders had higher shark catch and haulback mortality rates compared to monofilament. Hooking position is determined by the hook shape and width combined with bait. These characteristics also affect the ability to sever monofilament leaders.

Information on bycatch of Hector's dolphins in New Zealand waters was reviewed and new estimates were presented. Prior to 2008, 110-150 Hector's dolphins were estimated to be caught annually. Of these, 35-46 were caught of the east coast South Island. Between May 2009 and April 2010, an estimated 23 Hector's dolphins were caught of the east coast South Island. Previous risk analyses have shown similar results. Combined this information suggests continued overlap between Hector's dolphins and fisheries.

Observer data from European purse seine vessels operating in the Atlantic and Indian Ocean (1995-2011) were used to assess spatial and temporal variation in sea turtle bycatch rates. Information from both free swimming school sets and sets made on drifting fish aggregating devices (DFADs) was included in the analysis. Overall the results indicate purse seine fisheries have a very low impact on sea turtles. Annual, 218 and 250 individual sea turtles were estimated to be captured by purse seine's operating in the Atlantic and Indian Ocean respectively.

Information on seal bycatch in Irish fisheries were collected through an onboard observer program. The gillnet fishery had no observed bycatch of seals. Grey seals (Halichoerus grypus) and harbor seals (Phoca vitulina) were caught as bycatch in large mesh tangle nets targeting crawfish (Palinurus elephas). The west and southwest coasts of Ireland have a high risk for seal bycatch in crawfish fisheries due to the presence of grey seal colonies and similar habitat preferences.

The elasmobranch assemblage associated with the shrimp trawl fishery operating along the Pacific coast of Costa Rica was assessed. Trawl hauls were conducted between August 2008 and August 2012, resulting in the sampling of 4,564 elasmobranchs from 25 species and 13 families. The most commonly caught species (66% of the elasmobranch abundance) included the Panamic stringray (Urotrygon aspidura), rasptail skate (Raja velezi), brown smoothhound (Mustelus henlei) and witch guitarfish (Zapteryx xyster).

Six different acoustic pingers and signals were tested at sea to determine their impact on dolphin behavior. Two prototype devices from the Board Iascaigh Mhara (BIM) were tested. One was a continuous pinger (CP) and the second a responsive pinger (RP). These were tested on five occasions. A third modified RP was also tested on five occasions and a fourth RP was modified into a multiple signal output device and tested on 15 occasions. In addition, the CETASAVER and Dolphin Deterrent Device (DDD) were tested on five and ten occasions respectively.

Field testing was conducted  in the lower Bay of Fundy during 1996 and 1997 to determine the effectiveness of acoustic alarms (Netmark 1000) in reducing bycatch rates of harbor porpoises in gillnets. Alarms were spaced 100 m apart along the gillnet float-line. There was a 77% reduction in bycatch of harbor porpoises in nets equipped with alarms compared to those with no alarms. There were no significant differences in catch rates of target species, Atlantic cod, Atlantic herring and pollock. 

Four commercially available pingers (AIRMAR, Aquamark 100, Fumunda, Save Wave Saver) were tested on vessels operating in Cornwall targeting hake with gillnets. Pingers were tested for their effectiveness at reducing incidental interactions between the gillnets and porpoises. Only one of the four tested pingers, AIRMAR, performed 'satisfactorily'. 

A study was conducted in Sundarbans mangrove forest of Bangladesh to assess the behavioral response of Ganges River dolphins to pingers. Just under 62 hours of theodolite tracking data from 75 dolphin sightings and 2,829 theodolite fixes of dolphin surfacing were analyzed. The results suggest pingers had a subtle displacement effect on the dolphins. There was an increase in the mean surfacing distance of dolphins from the pinger buoy within a 100 m radius. Pingers did not result in a decrease in the minimum distance of approach for dolphins.

The impact of Medina panels attached to tuna purse seine nets operating in the US fishery was investigating for their effect on porpoise mortality. Medina panels are reduced mesh size netting hung from 2-inch mesh webbing on the purse seine. The authors took measurements of penetration of porpoise snouts and flippers through mesh openings of 2, 1 7/8, 1 1/2 and 1 inch to determine the potential reduction in porpoise entanglements. Even the smallest porpoise could not fit it's snout through the 1 inch panel, even with it's mouth closed.

Observer data collected between 2011 and 2014 from the Fijian longline fleet was analysed to characterize the shark and ray catch composition. In addition, factors that could significantly explain standardized catch rates were identified. Catch data were fitted to a generalized linear model to identify significant explanatory variables. The nominal catch rate for elasmobranchs was 0.610 per 1000 hooks. Twenty seven species of elasmobranchs were observed captured. Of the elasmobranchs captured, 48% are categorized as Threatened by the IUCN Red List.

Short term behavioral responses of Chilean dolphins (Cephalorhynchus eutropia) to acoustic alarms, or pingers, were tested using exposure-control experiments (pinger on/off treatments). Field trials were conducted in the south-eastern Chiloe Archipelago  between February and April of 2013. BananaBP154 pingers (FishTek Marine) were used for the tests. Static passive acoustic monitoring (PAM) techniques were used at two sites (Bahia Yaldad and Canal San Pedro) and land based observations, which included theodolite tracking, were also conducted at Bahia Yaldad.

Fisheries observer data from six gear types operating in the US Northeast and mid-Atlantic were analysed for seabird interactions. Between 1996 and 2014 an estimated 48,821 seabirds interacted with commercial fishing gear. This resulted in an estimated average interaction rate of 2,570 seabirds per year. The majority of interactions occurred in gillnet fisheries and involved shearwaters/fulmars. A comparison with previous work in the region was also conducted.

Bycatch interactions with deep-sea elasmobranchs are increasingly common and can lead to dramatic declines in abundance over short time scales. Sharks hooked in the deep sea could face a higher likelihood of severe physiological disturbance, at-vessel mortality, and post-release mortality (PRM) than their shallower counterparts.

Estimates of post-release mortality (PRM) rates for discarded bycatch are largely unknown across marine fisheries and represent a substantial source of uncertainty when estimating total fishery mortality. One way to predict PRM is through the use of reflex action mortality predictors (RAMP), whereby the presence or absence of target reflexes and known post-release fate are used to create a delayed mortality model.

Light-emitting diodes (LEDs) were mounted on the lower part of a Nordmore grid to determine if they would encourage fish to move up towards the escape outlet prior to contacting the grid. Trials were conducted to assess the size selective properties of a 19 mm bar spaced Nordmore grid with and without LEDs. The target in the fishery is deep water shrimp (Pandalus borealis). Small fish are bycatch, with 51-100% passing through the Nordmore grid.

The potential benefits of permanent magnets on ocean fish traps targeting snapper (Pagrus auratus) and their abiliy to reduce elasmobranch bycatch. The study deployed over 1000 traps in a fishery-dependent survey in New South Whales, Australia. The incorporation of magnets into fish traps significantly reduced incidences of elasmobranch bycatch by more than a thrid. At the same time, the target species catch rate was significantly increased. Magnets can therefore be used as an effective bycatch reduction device to reduce interactions with elasmobranchs.

Fishery data collected from the Reunion Island and Sechelles pelagic longline fisheries (targeting swordfish and tuna) between 2004 and 2015 was used to propose depredation indicators and to assess depredation levels in these fisheries. The interaction rate (depredation) was significantly higher for sharks compared to toothed whales in both fisheries. However, there was a higher depredation per unit effort from toothed whales compared to sharks indicating the impact was more significant. The gross depredation rate in the Seychelles fishery was 18.3%.

Experiments on the use of sea bird mitigation methods were conducted aboard Uruguayan pelagic longliners between 2010 and 2012. Experiments looked at the difference between setting bait at the sea surface and setting baits underwater. The researchers recorded the abundance of sea birds following the vessel and incidences of attacks on bait and mortality. When the bait was set underwater, there was a marked reduction in the number of seabirds following the vessel and attacks on bait.

This research examined the spatial and temporal characteristics of pilot whale habitat use and longline fishing effort. The information was used to assess the potential for a spatial management approach to mitigate pilot whale bycatch. The Area Under the Curve and Williamson's Spatial Overlap Index were both used to assess patterns of overlap and bycatch by applying them to telemetry data from short-finned pilot whales, longline fishery effort and Pelagic Observer Program (POP) data (2014-2015).