EFFECTS OF BOULDER DIAMETER OVER OPEN CHANNEL BED ON SWIMMING BEHAVIOR OF OPSARIICHTHYS PLATYPUS

Abstract

 It is important to keep suitable area by boulders to make rest area for fish. In this study, swimming behavior of Opsariichthys platypus in open channel were compared with change of the boulders diameter in over open channel bed. Swimming behaviors of Opsariichthys platypus were obtained with the aid of two sets of digital video cameras. It was found that Opsariichthys platypus preferred swimming in the behind boulders in cases when the boulders diameter is large. It is because that there are more low velocity spaces in this case compared with cases when the boulders diameter is small.