Effects of Water Temperature and Depth on the Catch Rate and Catch per Unit Effort for Mirror Carp (Cyprinus carpio) caught by Gillnets

Abstract

This study was conducted in Keban Dam Lake (38 degrees 49.271'N - 39 degrees 17.057'E) between July and March 2012 in Elazig, Turkey. In this study examined variations in CPUE fishing values of mirror carp (Cyprinus carpio) according to different hanging ratios (E=0.5, 0.67), materials (multi-monofilament and multifilament), water temperature, and water depth. CPUE values were found to be higher at 24.5 degrees C water temperature and 13.7 m water depth with multi-monofilament gillnets with a result of 15.23 g/m, and the lowest was with multifilament gillnets with a result of 3.95 g/m (0.5); however, multi-monofilament gillnets had a result of 23.28 g/m and multifilament gillnets 14.58 g/m (0.67) in July, respectively. Depending on the water temperature and the water depth, the CPUE values were higher in July than the other months. The lowest CPUE value was in March with 11.5 degrees C water temperature and 18.5 m water depth. Finally, these findings clearly show that increasing and/or higher temperatures supported higher CPUE values. In contrast increasing depths gave rise to a decrease in CPUE values.