Effectiveness of Bait and Unbait in Trapping of Astacid Crayfish

Bolat Y., Mazlum Y., GÜNLÜ A., Bilgin S., Izci L.

TURKISH JOURNAL OF FISHERIES AND AQUATIC SCIENCES, vol.11, no.2, pp.227-232, 2011 (SCI-Expanded) identifier identifier


The effectiveness of baited and non-baited traps was evaluated from June and December 2003 in Egirdir Lake. A total of 400 fyke-nets was set randomly along the shoreline at intervals of approximately 3 m, and hauled over 7 months. The mean catch per unit effort (CPUE) was found vary for sampling periods and treatments. In both treatments, average of CPUE were increased with increasing sampling periods. In addition, mean CPUE was found significantly different in both treatments (P<0.05). The overall average CPUE in non-baited traps were 2 times greater than baited traps. More crayfish occupant non-baited traps (n= 1947 traps, 69.5%) than baited traps (n= 945 traps, 33.7%). The larger and older crayfish were caught non-baited traps while baited traps had smaller size crayfish. Although there were significant differences in the capture of crayfish between non-baited and baited traps, but no differences were found males and females in both treatments for 7 months study. There was an obvious increased number of traps caught crayfish in both non-baited and baited traps from July to December. The catching of crayfish had been prohibited by law until 1999 in Lake Egirdir. When catching of crayfish was allowed again, fishing potential increased gradually each season. Crayfish behaviour appears to have the most effect on catch per unit trapping effort, but without bait can improve the overall catch. Improvement in harvesting efficiency can be achieved by developing trap designs that maximize catch while minimizing escape of crayfish.