Feeding events of Japanese lates Lates japonicus detected by a high-speed video camera and three-axis micro-acceleration data-logger
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- Tanoue, H., Komatsu, T., Tsujino, T. et al. Fish Sci (2012) 78: 533. doi:10.1007/s12562-012-0470-z
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The feeding events of wild animals have been widely researched in recent decades. The use of invasive methods to determine stomach contents in which the fish is killed can, however, be considered to be unjustifiable in the case of an endangered fish, such as the Japanese late. Here, we report on a method that can be used to verify feeding events of a fish species without the need for killing the fish through the use of a high-speed video camera and a three-axis micro-acceleration data-logger. High-quality images obtained by the video showed that the fish opens its mouth with a quick downward movement of the mandibles and ingests prey via suction feeding. The movement of the mandibles was also simultaneously recorded by changes in the three-axis accelerations obtained by the logger attached to the dorsum. We attached the logger with an automatic release system to the dorsum of one captive Japanese lates and two wild fish together with an acoustic transmitter and then released the fish in the Shimanto River in Japan. After retrieving the logger, the movement records of the fish obtained by the three-axis accelerometer showed the same pattern of feeding events as those in captivity. A total of 13 feeding events at night and five during the daytime were obtained for the three fish during a total 129.7 h of recording.