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Between 2019 and 2022, trials using three different pinger models (Future Oceans 10 kHz, Future Oceans 70 kHz, and PAL Wideband) were conducted in Bulgaria during standard turbot (Scophthalmus maeoticus) fishing operations. Marine mammal bycatch was observed in  61% of all hauls. No significant difference in bycatch rates between active and control nets was observed in trials involving Future Oceans 10 kHz (17 trials) and 70 kHz (6 trials) pingers. However, a significant reduction (74%) in cetacean bycatch was recorded during the trials conducted with PAL Wideband pingers. 

This study evaluated the effectiveness of using plastic drink bottles as low-cost acoustic reflectors to reduce franciscana dolphin (Pontoporia blainvillei) bycatch in bottom-set trammel nets and gillnets off of southern Brazil. The bottles achieved an 88% reduction in dolphin bycatch per unit effort compared to control nets. In addition, the bottles had no significant impact on commercial target species catch (by weight). 

The study tested the use of glass and plastic drink bottles as low-cost bycatch mitigation devices (mechanical pingers and acoustic reflectors, respectively) in gillnet fisheries across three regions/fisheries: surface-set driftnet fisheries in Zanzibar and Peru and bottom-set trammel net fisheries in Brazil. In Brazil, plastic bottles reduced dolphin bycatch while increasing fish catch, although further trials are needed. In Peru, glass bottles had no effect on dolphin, porpoise, or turtle bycatch but altered target elasmobranch and teleost catches; plastic bottles similarly had no effect on dolphin bycatch but increased shark catch. In Zanzibar, no dolphin bycatch was recorded in any sets, though plastic bottles increased tuna catch. 

The study tested the use of glass and plastic drink bottles as low-cost bycatch mitigation devices (mechanical pingers and acoustic reflectors, respectively) in gillnet fisheries across three regions/fisheries: surface-set driftnet fisheries in Zanzibar and Peru and bottom-set trammel net fisheries in Brazil. In Brazil, plastic bottles reduced dolphin bycatch while increasing fish catch, although further trials are needed. In Peru, glass bottles had no effect on dolphin, porpoise, or turtle bycatch but altered target elasmobranch and teleost catches; plastic bottles similarly had no effect on dolphin bycatch but increased shark catch. In Zanzibar, no dolphin bycatch was recorded in any sets, though plastic bottles increased tuna catch. 

The study tested the use of glass and plastic drink bottles as low-cost bycatch mitigation devices (mechanical pingers and acoustic reflectors, respectively) in gillnet fisheries across three regions/fisheries: surface-set driftnet fisheries in Zanzibar and Peru and bottom-set trammel net fisheries in Brazil. In Brazil, plastic bottles reduced dolphin bycatch while increasing fish catch, although further trials are needed. In Peru, glass bottles had no effect on dolphin, porpoise, or turtle bycatch but altered target elasmobranch and teleost catches; plastic bottles similarly had no effect on dolphin bycatch but increased shark catch. In Zanzibar, no dolphin bycatch was recorded in any sets, though plastic bottles increased tuna catch. 

Experimental trials were carried out in Argentina comparing franciscana (Pontoporia blainvillei) 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.  

Experimental trials were carried out in Argentina comparing franciscana (Pontoporia blainvillei) 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.  

Potential risk of fisheries to cetaceans was assessed using a screening procedure based on a Productivity Susceptibility Analysis (PSA) using gears found in Ireland. Gillnets targeting demersal species was assessed as the fishery posing the greatest risk to cetaceans. Pelagic trawls targeting small pelagic species was found to pose a moderate risk to cetaceans. Specific gear-species interactions were also identified, such as humpback whales (Megaptera novaeangliae) and pots/traps.  

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. 

Small cetaceans are by-caught in salmon gillnet fisheries in British Columbia (BC) waters. In Canada, there is currently no generic calculation to identify when management action is necessary to reduce cetacean bycatch below sustainable limits. The researchers estimated potential anthropogenic mortality limits for harbour (Phocoena phocoena) and Dall’s (Phocoenoides dalli) porpoises and Pacific white-sided dolphins (Lagenorhynchus obliquidens) using quantitative objectives from two well-established frameworks for conservation and management (the United States’ Marine Mammal Protection Act and the Agreement on the Conservation of Small Cetaceans of the Baltic and North Seas), which are similar to some management objectives developed for marine mammal stocks elsewhere in Canada. Limits were calculated as functions of (i) a minimum abundance estimate (2004–2005); (ii) maximum rate of population increase; and (iii) uncertainty factors to account for bias in abundance estimates and uncertainty in mortality estimates. Best estimates of bycatch mortality in 2004 and 2005 exceeded only the most precautionary limits and only for porpoise species. Future research priority should be given to determining small cetacean stock structure in BC and refining species-specific entanglement rates in these and other fisheries. The approach offers a quantitative framework for Canada to meet its stated objectives to maintain favorable conservation status of cetacean populations.