1Graduate School of Marine Science and Technology, Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, 2Tokyo University of Marine Science and Technology, Minato, Tokyo 108-8477, Japan
To study conger eel tube fishery in Tokyo Bay, we developed equipment to measure the time at which conger eel first entered the tubes and, after testing the equipment in the laboratory, conducted field experiments around Naka-no-Se, Tokyo Bay. A total of 192 experimental tubes were deployed and 85 of them were successfully measured. Conger eels are generally known to be active at night; however, in this study, even though the tubes were deployed during the daytime, 35% of the first entry times were within one hour after deployment and 63% of them were before sunset.