Monitoring the behavior of young bluefin tuna Thunnus orientalis and yellowtail Seriola quinqueradiata in set nets using ultrasonic biotelemetry

Abstract

As the resource management of bluefin tuna Thunnus orientalis is becoming increasingly important, a new technology for set-net fisheries to separate young bluefin tuna from other catches is needed. If behavioral diŠerences in a set net between bluefin tuna and other species could be detected, it would help to develop such new technology. In this study, we used an ultrasonic telemetry system to study the behavior of young bluefin tuna and yellowtail Seriola quinqueradiata in a set net. The results showed that bluefin tuna swim back and forth between the second bag net and the first bag net, while yellowtail swim all the way into the final net. These behavioral diŠerences could be used in the development of a technology to separate young bluefin tuna from other catches in set nets.