COMPARISON OF TRAP AND BAITED STICK CATCH EFFICIENCY FOR NOBLE CRAYFISH (ASTACUS ASTACUS L.) IN THE COURSE OF THE GROWING SEASON

摘要

Noble crayfish (Astacus astacus) were caught using traps and baited sticks in Sv?tlohorská reservoir in the Czech Republic, and the catch efficiency and size and sex composition in catches were compared during the growing season (May-September). One trapping period per month (1.5 hour from 6-7: 30 pm) was applied. Trap catches were significantly higher in September compared to the other months, and baited stick catches were significantly higher in May, June and September. Baited sticks were significantly more effective than traps in all months except in July. Males dominated in all catches, except in September trap catches. Females were totally absent in traps in June, July and August. Baited sticks caught females more successfully than traps, especially females with eggs. Traps did not catch any females with eggs. Males and females caught by baited sticks were of larger size range (range of body length 60-125 mm) than those caught by traps (range of body length 75-120 mm) however, there were no significant differences in mean size. Due to high catch efficiency, baited sticks may be considered as an appropriate catching gear in crayfish monitoring projects, especially when a short-time catching effort is required.