Effects of Microcystins and Malachite Green on the Swimming Behavior of Tilapia nilotic and Micropterus salmoides
MC与MG对尼罗罗非鱼和大口黑鲈游泳行为的影响

Tilapia nilotica and Micropterus salmoides, main freshwater commercial fish species of China, are usually threatened by Microcystin (MC) and malachite green (MG) in aquaculture. They also become serious threat to human health via acumulating in human body. This study investigated the swimming behavioral responses of Tilapia nilotica and Micropterus salmoides in exposure to water with different concentrations of MC or MG. The results showed that when exposed to 2 μg/L MC or 5 μg/L MC, no significant swimming behavior response of Tilapia nilotica and Micropterus salmoides were observed. However, when exposed to 5 μg/L MG, the frequency of swing pectoral fins of Tilapia nilotica increased significantly after 30 min, and the frequency of swing pectoral fins of Micropterus salmoides changed notably at 25 min,30 min and 45 min. The results indicate that both Tilapia nilotica and Micropterus salmoides have a strong resistance to the natural toxin MC, but are more sensitive to the artificial toxin MG. The frequency of swing pectoral fins can thus be used as a behavioral indicator of environmental changes.