Abstract
Electronic monitoring systems (EMS) have increasingly been used as an alternative technology to complement onboard observer programs and improve the management of tuna fisheries. EMS was installed on French purse seiners in 2014 in the frame of the OCUP program and pilot studies have shown that the system allows in-depth monitoring of fishing activities by providing information on catch composition and handling on deck and below deck. In this study, we further explore the potential of EMS for monitoring the hauling process of tropical tuna purse seiners' catch from the net to the deck. Using information collected during brailing (number of brailers, timing, fullness) on board 5 vessels of the Indian Ocean during 2018-2019, we evaluate the suitability of EMS as a tool to describe the main trends in brailing operations over 50 fishing sets. Our results indicate a large variability in brailer fullness among fishing sets and a relatively fast loading of the catch onto the deck with brailing operations generally consisting of 4 to 5 brailers transferred on board in less than 15 minutes. Results confirm the potential of EMS for collecting complementary data to monitor brailing operations of tropical tuna purse seiners.