Model experiments on the catching mechanism of a small shrimp pot-IV. Daily variations in the number of prawns in small prawn pots.

Abstract

The number of creatures remaining in a pot may be closely related to the pot construc-tion and the degree of interaction between the captured individuals in the pot, influenced by its passive catching function. We examined aspects of escape and capture of Macrobra-chium nipponense in small prawn pots under actual fishing conditions. The number of in-dividuals in a pot changed in an oscillatory pattern. The entry and escape of small prawns was an important factor in daily variations in the number remaining in a pot. There was no difference in the mean values of animals remaining obtained under different conditions. There was a similarity between the period for a peak catch in the experimental results and findings from actual operations.