Tropical tuna biomass indicators from echosounder buoys in the eastern Pacific ocean

The collaboration with the vessel-owners associations and the buoy-providers companies operating in the Pacific Ocean, has made it possible to obtain information recorded by the satellite linked GPS tracking echosounder buoys used by some of the tropical tuna purse seiners in the Eastern Pacific Ocean since 2010. These instrumental buoys inform fishers remotely in real-time about the accurate geolocation of the FAD and the presence and abundance of fish aggregations underneath them. Echosounder buoys have the potential of being a good observation platform to evaluate abundances of tunas and accompanying species using catch-independent data. Current echosounder buoys provide a single acoustic value without discriminating species or size composition of the fish underneath the FAD. Therefore, it has been necessary to combine the echosounder buoy data with fishery data, species composition and average size, to obtain a specific indicator. This paper presents a novel index of abundance of skipjack tuna in the Eastern Pacific Ocean derived from echosounder buoys for the period 2012-2020.