A study by the NGO The Nature Conservancy shows significant differences in catches recorded with EM versus manual methods

Electronic observation systems on board fishing vessels (also known as Electronic Monitoring or EM) are the most accurate and reliable source of data for the development of selective fishing practices and for the control of compliance with management measures because of their ability to be verified. 

23 February 2022

Electronic observation systems on board fishing vessels (also known as Electronic Monitoring or EM) are the most accurate and reliable source of data for the development of selective fishing practices and for the control of compliance with management measures because of their ability to be verified. This is the main conclusion of a study[1], coordinated by the environmental organization The Nature Conservancy, which shows the remarkable differences between catch and bycatch records obtained with EM systems versus those recorded in traditional logbooks.

The research has been carried out on 15 ships dedicated to tropical tuna longline fishing in the Western Pacific and equipped with the electronic monitoring system of the Spanish technological company Satlink, called SeaTube. Specifically, the researchers have analyzed the data collected by this solution from a total of 98 trips in the Exclusive Economic Zones (EEZs) of Palau, the Federated States of Micronesia and the Republic of Marshalls Islands.

According to the study, the biggest difference between the two recording systems occurred in the case of yellowfin tuna (Thunnus albacares) caught in Palau waters, whose estimated catches calculated from the EM are up to 1.3 (30%) times higher than those recorded in the logbooks. Likewise, also in Palau, estimates of shark bycatch calculated from EM were almost eight times higher than those obtained from logbooks. In addition, according to the study, the EM system identifies a greater variety of species in each haul, specifically, between eight and ten, compared to those shown by the logbooks, approximately five to eight.

In this sense, the authors point out that the widespread use of these systems by governments and Regional Fisheries Management Organizations (RFMOs) would improve the accuracy of target and non-target catch reporting, including species whose populations are in decline, and would provide more reliable data for scientific assessments on which to base more precise measures for sustainable resource management.

The authors also stress the value of these systems for improving the management of fisheries that, like the Pacific longline fishery, have low human observer coverage, with a minimum rate of 5% recommended by the Western and Central Pacific Fisheries Commission (WCPFC) and the possibility of increasing this rate to 20% as recommended by scientific organizations.