Effect of Different Funnel Designs on the Catching Ability of Small Pots for Prawns Macrobrachium nipponense

抄録

The number of entrapped prawns in a pot may be controlled by the funnel entrancedesign. The catching ability of small prawn pots was studied. To clarify how thepot funnel design affects the number of prawns in a pot, a series of test werecarried out with model pots withoutbait in the south-basin fishing ground of Lake Biwa, Japan. The data used in the evaluation were the catch of 249 test trials by prawn pots in six years (2 October 1986-26 December 1991). The variations in therelative catching index, R_i, could be explained satisfactorily by the differences in the funnel designs.
The pot used here had a characteristic effect forany one funnel design on the number of prawns entrapped. The results suggest that the diameter of the opening and the height of the funnel strongly control the number of entrapped prawns.