The investigation of catch efficiency of crayfish fyke nets located in different duration

Objective: This study was carried out to determine the effect on catch performance, weight and sexual distribution of soaking duration of fyke nets used crayfish fishing. In this way, it was tried to procure more yield by less effort. Methods: The investigation surveys were performed in the fishing areas called Keban, Cemisgezek and Agin in the Keban Dam Lake. In the study, three sets of fyke nets, which consist of fifty fyke nets, were used. The fyke nets were found along shore in similar deeps one after another on the same day. The same conditions for each set of fyke nets were procured because season, structure of floor and deep are significantly affect the catch capacity. The first set, the second set and the third set were steeped for three days, five days and seven days, respectively. The crayfish caught were separated as male and female, and then their numbers and weight were determined. Four fishing trials were conducted and a total of 1412 crayfish were caught. Results and Discussion: It was identified that the crayfish caught were 77.26 % male and 22.24 % female. 14.16 %, 29.11 % and 54.74 % of total catch were caught by fyke nets steeped for three days, five days and seven days, respectively. In the fyke nets steeped for seven days in fishing area, 26.07 % of total catch entered into gears in the first three days, 25.69 % in 4th and 5th, 48.24 % in 6th and 7th. Catch per unit effort (CPUE) was calculated as 0.35, 0.41 and 0.57 crayfish/fyke net/day for the first set, the second set and the third set, respectively. Ratios of male and female were determined to be 3.93, 4.20 and 3.11. Common weights were determined as 36.29, 33.98 and 33.05 for male, 24.21, 22.71 and 24.07 for female, respectively. In the present study, it was concluded that the most efficient catching could be obtained by fyke nets steeped for seven days. In this catching method used by local fishermen, it has been evaluated that highest yield can be harvested by using the less effort. The more fishing period increases the more ratios of male and female decrease. It has been thought that this circumstance has arisen from what the crayfish desire to use as a shelter to fyke nets which they get used to presence, because of female crayfish whose total length less than male crayfish need more protection. Due to same reason, the more fishing period increases the more total length of crayfish that stayed in fyke nets decreases