Abstract
The fishing mechanism of fish pots was studied through both field research and laboratory experi-ments using puffer, Fugu niphoble. Sizes of fish pots and puffer, Lagocephalus wheerleri caught were measured on board. As a first step to investigate swimming motion near the entrance to pots, the behavior of fish at the entrance to a simplified pot set in the aquarium were recorded on video tape and investigated using a motion analyzer. The following results were obtained.
The turning motion of fish varied with the width of the pot's entrance “…when the ratio of the width of the pot entrance to the total length of the fish was less than 0.78.” However, no turning motion was observed when the ratio fell below 0.57. These values appear to be the upper and lower limits for the turning motion of fish in the pot's entrance. The numbers of fish caught estimated from tank experiments agree well with the field research. The fish-catching mechanism of fish pots seems to depend on the behavior of the fish inside the pot's entrance.
