Species selectivity of fish basket

To demonstrate the species selectivity of fish baskets, fishing experiment was conducted using baskets of iron frame covered with netting in a rocky ground. The baskets were baited with frozen sardine (baited basket) or partly covered with brushwood on their top (covered basket) and their catches were compared with that of the control (without bait and brushwood). The total catch from 156 hauls was much better in the covered baskets and baited ones than in the control. The influence of the bait and brushwood on the catch was fish species selective; the filefish was significantly dominant in the catch of the covered baskets, the grass puffer was caught only by the baited baskets, and no influence was seen in the wrasse and striped catfish. A tank experiment implied that the species selectivity was different between day and night; the rockfish and filefish ingressed preferably into the covered basket in daytime but into the control at night. An exploratory behavior was hypothesized for the ingress of the fishes into the control, and the brushwood was thought to enhance an exploratory drive of fish.