Evaluation of cage traps to control the invasive signal crayfish (Pacifastacus leniusculus) in Lake Harutori

Abstract

 We conducted a comparative experiment to investigate the suitability of cage traps for efficiently capturing invasive crayfish (Pacifastacus leniusculus) in Lake Harutori, Hokkaido, Japan. For the experiment, we set up three types of cage traps (conger cage, crab cage and shrimp cage) in five spots along the lakeside. The result of the experiment revealed that the numbers of P. leniusculus captured were significantly higher for the conger cage than for the other cages. In addition, both the smallest individual and the largest individual of all captured individuals were captured by the conger cage. Moreover, the averages of body size of captured individuals were no significantly different between conger cage and the other cages. Thus, we concluded that the conger cage is the most efficient trap to capture crayfish in Lake Harutori.