Comparing Electronic Monitoring and human observer collected fishery data in the tropical tuna purse seine operating in the Pacific Ocean

Citation
Murua H, Herrera M, Morón J, et al (2020) Comparing Electronic Monitoring and human observer collected fishery data in the tropical tuna purse seine operating in the Pacific Ocean. In: IATTC - 11th Meeting of the Scientific Advisory Committee. IATTC-SAC-11 INF-G REV, Electronic Meeting, p 25
Abstract

Electronic Monitory (EM) systems have been proven a valid tool for collecting fishery dependent data. They are being widely used in many fisheries as a complement or alternative to human observers to increase the monitoring coverage of fisheries. However, considering its wide application, following agreed minimum standard, it is important to compare the congruence between the information collected by EM and observers. We compared EM and observer data collected on 7 trips of tuna purse seiners in the Eastern and Central Pacific Ocean to analyze the similarity of fishing set type identification, estimation of tuna and bycatch catches between both monitoring systems. Overall EM was a valid tool to estimate the type of fishing set. Retained total catch of tunas by set was estimated by EM as reliable as that by observers/logbook. When comparing the information by set, EM estimation of the main species, such as skipjack and bigeye and the combination of bigeye/yellowfin, was proven to be less accurate but statistically similar to the estimates made by observers. For bycatch species, EM allows to identify main bycatch species as observers do. For large individuals, such as sharks, billfishes and, to a lower extent, large bony fishes, EM identified a similar overall number of individuals when considering all trips together. For sharks, which are the main bycatch issue in the FAD purse seine fishery, the congruence between EM and observer was high.