Efficiency of a Small Pot for Oriental River Prawn Macrobrachium nipponense in Terms of Entry and Escape

Abstract

The construction of the pot entrance may be reflected in the degree of the change in the individuals in a pot. The efficiency of a small pot for Macrobrachium nipponense was studied. To clarify how the pot entrance design affects the efficiency of a pot, a series of tests were carried out under actual fishing conditions. The prawn's entry and its escape behavior was observed frequently and the length of the individual's stay in a pot was relatively short. The variations in the efficiency could be explained by the differences in the funnel design of h (height of neck)/d (diameter of opening). The apparent efficiency was maximum at h/d=3.1. The results suggest that the interaction between individuals in a pot is controlled by the funnel design.