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Fisheries‐dependent data underpin essential scientific and management applications. Electronic monitoring (EM) systems are increasingly being used to supplement human observer programmes and provide coverage where none previously existed. Candidate methods were identified to expand EM functionalities to collect data fields of human observer programmes that contemporary EM systems either cannot collect or require improved accuracy. Options were also identified to enable EM systems to collect new data fields that human observers cannot collect, prioritized by scientists, managers and the catch sector. Many EM limitations could be resolved through simple changes of repositioning existing or adding new cameras with suitable fields of view and resolution, integrating additional sensors, and making minor modifications to fishers' practices. Research, development and trials, however, are required for possible EM integration of some existing and emerging technologies. Whether an EM improvement method should be pursued requires consideration of: the relative importance for meeting monitoring objectives; the accuracy and cost of alternative monitoring methods, such as data collection by fishers with EM auditing, and by dockside inspections; impacts on fishing operations and crew safety; and net costs. Active support from fishers is necessary for EM collection of some data fields, where EM enables auditing fisher compliance with required procedures. Having EM systems supply data desired by the seafood industry could augment their support for EM and incentivize fisher cooperation. EM systems have the capacity to collect most data fields collected by human observer programmes with high precision and in some cases improved accuracy, to supply information of interest to seafood companies, and to meet expanding data requirements as fisheries management frameworks continue to transition to implementing elements of ecosystem‐based fisheries management.

The collection of accurate fisheries catch data is critical to ensuring sustainable management of tuna fisheries, mitigating their environmental impacts and for managing transboundary fish stocks. These challenges are exemplified by the western Pacific tuna longline fishery, who’s management includes >26 nations, but is informed by critically low coverage of fishing activities by scientific observers. The gap in observer data could be filled by electronic monitoring (EM), but there are few trials that span multiple nations. A large-scale trial of EM systems on tuna longliners based in Palau, Federated States of Micronesia and the Republic of the Marshall Islands, is reported on. Comparisons are made of catch rates of market and bycatch species in corresponding EM, logbook and human observer data. Retained species were under-reported in logbooks by up to three times and discards of many species were not reported in logbooks. Discards identified in the EM data included threatened species such as marine turtles. Catch rate estimates from EM data were comparable to those estimated by human observers. EM data recorded a higher species diversity of catches than logbook data. Analysis of the EM data indicated clusters of bycatch that were associated with specific fishing practices. These results suggest further expansion of EM could inform improved management of both target and bycatch species. Ultimately greater coverage of EM data could contribute to reconciling debates in international stock allocation schemes and support actions to reduce the impacts of the fishery on threatened bycatch species.

Bycatch of sharks in longline fisheries has contributed to declines in shark populations and prompted the need for exploring novel technologies to reduce the incidental capture of sharks. One potential strategy is to exploit the unique electrosensory system of sharks, used to detect weak electric fields. Metals from the lanthanide series, made up of neodymium (Nd) and praseodymium (Pr), produce strong electric fields in water. In this study, we tested the effects of an Nd/Pr alloy on shark catch rates. Using longline fishing gear, we compared the catch rates of baited hooks affixed with either a block of the metal alloy (experimental) or a lead weight (control). Four experiments were conducted in different regions of the Pacific Ocean. Two bottom longline experiments were conducted inside and offshore of Kaneohe Bay, Hawaii. One of these experiments targeted young of the year scalloped hammerhead sharks (Sphyrna lewini), while the other targeted sandbar (Carcharhinus plumbeus) and tiger sharks (Galeocerdo cuvier). In the Southern California Bight (SCB), pelagic longlines were deployed to target mako (Isurus oxyrinchus) and blue sharks (Prionace glauca) and longlines targeting pelagic sharks were set in the Eastern Tropical Pacific (ETP) off Ecuador. There was a significant reduction in juvenile hammerhead sharks caught on hooks with the lanthanide metal compared to the controls. In contrast, there was no difference in the catch rates for experiments targeting sandbar sharks in Hawaii or those conducted in the SCB and Ecuador. These results suggest that there are inter-specific differences regarding the effects of lanthanide metals on catch rates. This may reflect the diverse feeding strategies and sensory modalities used by shark species for detecting and attacking prey.