In order to analyze the capturing mechanism of pot traps, fish behavio
r was observed in and around a trap using an underwater TV system. The
behavior pattern was classified as follows: 1 appearing in the camera
view, 2 swimming towards the entrance, 3 entering inside the funnel,
4 eating the bait, 5 going backward foward the funnel, 6 passing throu
gh the inner opening, 7 swimming out of the camera view. During the 1,
150 min of observed period, total numbers of appearances were 131 time
s, entering inside the funnel 57 times and capture 3 times, respective
ly. The puffer swan backward from the funnel by paddling the pectral f
ins foward the snout of the fish. The capturing mechanism of the fish
trap seemed to be affected by the freedom of swimming behavior of puff
er fish inside of the funnel.