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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 stingray (Urotrygon aspidura), rasptail skate (Rostoraja 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.

Observer data collected between 2011 and 2014 from the Fijian longline fleet was analyzed 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 ((Prionace glauca; 51% of sharks) and pelagic stingrays (Pteroplatytrygon violacea; 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'. 

The study tested the use of a modified turtle excluder device (TED) - using substantially reduced grill spacing - in order to reduce elasmobranch bycatch in the Guyanese seabob shrimp (Xiphopenaeus kroyeri)  fishery. The use of the modified TED resulted in a significant reduction (by 40%) of the bycatch rate of elasmobranchs. The TED also was highly effective in reducing the capture of three "Near Threatened" ray species. However, the TED preferentially released larger-sized individuals, meaning that smaller-sized individuals and species, including the "Critically Endangered" Bancroft's numbfish (Narcine bancroftii), were still captured by the trawl. Since the modified TED was generally successful in reducing important elements of elasmobranch bycatch, future study will extend the study to determine the impact of the TED on the capture rate of the target seabob shrimp. 

Global Bycatch Exchange note (2026): In 2017, a re-evaluation of available information found that the Bancroft's numbfish is not at risk of extinction, although population trends are highly variable. It is currently classified as a species of "Least Concern" by the IUCN. 

Illuminated nets were tested to evaluate their effect on catch and bycatch in set nets, principally green (Chelonia mydas) and loggerhead (Careta caretta) sea turtles, in northern Cyprus. Reductions in the catch of sea turtle and non-target sharks and rays were recorded with no effect on target catch. Data were collected from 130 field sets that occurred over a two-year period. Experimental effort should be expanded to better ascertain the relationship between the illuminated devices used and sea turtle bycatch reduction.

The present study was designed to incorporate stakeholder input and fisher expertise in the design of mobulid (mantas and devil rays) bycatch technology in large-scale tuna purse seine fisheries operating in the EPO (Eastern Pacific Ocean). Surveys and focus groups of fishers suggested that the primary obstacles to mitigating mobulid bycatch are 1) inability to sight them before capture, 2) lack of appropriate response equipment on board, and 3) the difficulty of releasing large individuals. Many suggestions were made for both pre-capture and post-capture bycatch mitigation strategies.

A mobuilid sorting grid placed over the hopper used to sort bycatch on tuna purse seine vessels aided in the release of larger mobuilid rays without increasing handling time.  

Elasmobranch bycatch significantly decreased in bottom-set gillnets in the Gulf of California, Mexico using orange LEDs, ultraviolet LEDs, green LEDs, and green glow sticks, with orange LEDs being the most effective at reducing bycatch. As a whole, catch of bony fish was not affected by illumination, although responses were taxonomic-specific.  

The catches from five experimental trawls (TED + fisheye BRD, upward facing TED, downward facing TED, bigeye BRD and square-mesh panel BRD) were compared to those of the standard twin Florida Flyer prawn trawl. Nets with a combination of a TED and BRD reduced sea turtle catches by 100%, large sponges by 85.3%, sharks by 36.3% and rays by 17.7% and reduced the proportion of soft and damaged prawns by 41.6% and catches of tiger prawns by 6.5%. Upward and downward facing TEDs reduced sea turtle bycatch by 99% and 100% respectively and large sponges by 81.6% and 95.9% respectively. Catches of tiger prawns (P. semisulcatus and P. esculentus) were reduced by 6.3% with the use of TEDs. The BRDs had little impact on the catch of either target or bycatch species.

The study evaluated if green LED lights and pulsed electrical deterrents (SharkGuard) could reduce bycatch of threatened elasmobranchs in Northern Australia gillnet fisheries. 23 paired deployments of LED lights (Fishtek Marine) and 7 electric deterrent trials were analyzed. Nets with green LED lights caught 35% fewer elasmobranchs, while also resulting in a significant increase (76%) of bony fish catch (however, commercially-targeted species of bony fish were not caught significantly more in the LED nets). Electric deterrents did not significantly reduce bycatch or fish catch, however, the small sample size limits the ability to detect meaningful effects. Both green LEDs and electric deterrents showed moderate effects related to reduced sawfish (Pristis clavata, P. zijsron, Anoxypristis cuspidata) catch per unit effort (CPUE), particularly for the electrical deterrents, which could be explored in a larger study. 

The addition of a prototype "tunnel excluder" consisting of a filter grid (inclined at ca. 20 degrees) that leads to an escape tunnel in the Mauritanian industrial trawl fishery nets achieved a 40-100% reduction in bycatch of vulnerable species, including allowing 100% of rays and turtles to escape, 75% of manta rays, 40% of billfish and between 20-75% of sharks to escape. Cetaceans were less likely to use the tunnel to escape due to the narrowness of the design.