Pilot study on the movement of Mekong giant catfish in the reservoir

Abstract

Mekong giant catfish Pangasianodon gigas is endangered species. It is urgently necessary to learn more about the movement pattern of the catfish to conserve. We started the Mekong giant Catfish Tracking Project (MCTP) that is ecological research cooperative with Thai government at 2001. In this paper, the first results of MCTP are introduced. Horizontal and vertical movements of Mekong giant catfish were determined using pressure-sensitive ultrasonic transmitters in the reservoir. We found the clear daily movement patterns of the catfish. The catfish appeared to favor relatively deep areas and had 2-3 km excursions at night. The catfish exhibited the ascent to the surface at dusk and the descent to the thermocline at dawn in the reservoir. These behaviors of the catfish might be related to the feeding behavior.