Flow, Temperature And Weight Influence On Bream (Megalobrama Amblycephala) Juvenile Swimming Behavior And Standards Metabolism

It is well known that many bio tic and abiotic factors could influence the fish survival and reproduction.For example, the ecological effects of water rate and water temperature on the fish growth, predation and embolism are significant.Therefore, it is helpful to understand the mechanism that fish adapt to the envirment change, through discolsing the impact of some critial environmental factors, such as water rate and water temperature, on fish swimming behaviors.Megalobrama amblycephala, a still water fish, belonging to Cypriniformes, Cyprin idae, Culterinae, is one of main cultured freshwater fish in our country with a great p otential for aquaculture. While a large amount of studies published on physiology, nutr ition and gene of juvenile M. amblycephala very limited litratures involved in the phy siological and ecological researches on the swimming behavior and energy metabolism of fish in the surrounding environment.To investigate the effects of water velocities and water temperatures on the swim ming behavior of juvenile M. amblycephala, a series of experiments were conducted at four water velocities (Om/s、0.1m/s、0.2m/s、0.3m/s and0.4m/s), three water tempera trues(21℃、25℃and29℃) and two weight groups (L and S) using a special tracking analysis device. Furthermore, the effects of water temperature and body weight on th e standard embolism was conducted in juvenile M. amblycephala using using a aquati c organisms breathe measuring instrument. The results are listed as follows:(1) Effects of water velocity on swimming behavior of juvenile M. amblycephalaThere were no significant difference of water velocity on velocity, swimming distance, turn angel and distance to center-point under the same water velocity. The velocity, swimming distance and turn angle did not change markedly with the rates increasing. However, swimming track became more complex as the increasing of water temperature.(2) Effects of water temperature on swimming behavior of juvenile M. amblycephalaThere were no significant effects of water temperature on velocity, swimming distance, turn angel and distance to center-point under the same water velocity. The velocity, swimming distance and turn angle did not change markedly with the rates increasing. However, swimming track became more complex as the increasing of water temperature.(3) Effects of water temperature on Rs of juvenile M. amblycephala.There were significant effects of temperature on Rs of juvenile M. amblycephala. Whaterever the weight is, the Rs’and Rs of M.amblycephala increased with the increasing of temperature, respectively. Besides, the Rs’ had a significant circadian rhythm.There were markedly correlation relationship of indices between temperature and Rs.(4) Effects of weight on Rs of juvenile Megalobrama amblycephala.The Rs of juvenile M. amblycephala belong to L group exceeded the Rs of S gr oup under the same water temperature. However, the Rs’ of L group was smaller the Rs’ of S group. Meanswhile, there was less effect of water temperature on the Rs’ of L group than the Rs’ of S group.