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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. Shark catch rates and deep hooking were increased when fish was used for bait compared to squid. Wider hooks resulted in reduced pelagic stingray catch and mortality.

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. The risk analyses indicate that Hector's dolphin populations could recovery to 15,000 individuals (from 7873) over the next 50 years if there was no fishing mortality. Risk analyses all indicate that the population of Hector's dolphins has declined substantially due to fishing mortality. Current management and  recovery actions are unlikely to to result in recovery of this species. 

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. The majority, 75%, of these turtles were released alive. The study also suggests that DFADs may play a role in aggregating juvenile sea turtles.

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). Elasmobranch species richness was significantly higher at depths less than 100 m, compared to deeper depths. In addition, size and sex distribution is influenced by depth of fishing. The movement of this fishery into shallower waters could be problematic for elasmobranch bycatch.

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. The BIM and RP acoustic pingers did not elicit any response from the dolphins. The CETASAVER and DDD elicited a mild response. The authors suggest significant modification to the signal type or source level. At the current state of development acoustic pingers may not provide effective deterrent signals to dolphins.

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. Pingers did not change the frequency of sightings detected within 100 m of the pinger buoys. The results remain unclear whether pingers would be able to prevent entanglement in gillnets by Ganges River 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. Recent tests of porpoise 'aprons' and 'chutes' could be promising in making these small mesh panels compatible with tuna purse seine performance.

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. Sharks and rays made up 2.4% and 1.4% of the total catch respectively. The most commonly caught elasmobranchs were blue sharks (51% of sharks) and pelagic stingrays (99% of rays caught). Significantly higher catch rates were observed on narrower J-shaped hooks compared to wide circle hooks. Catch rates of sharks and rays were lower during the latter half of the year. The fishery does not use 'shark lines'.