USGS Home
Contact USGS
Search USGS

Search fish passage bibliography

Zhao, X. and Z. Han (1980). Experiments on the current overcoming ability of some freshwater fishes. Journal of the Fishes of China. 4:31-37.

The ability of fish to overcome currents should be the first consideration in designing the inlet of a fishway according to the authors. A series of experiments were conducted in the flume of a hydraulic laboratory. Various kinds of fishes were selected for the experiments, such as common carp Cyprinus carpio; Crucian carp Carassius auratus; silver carp Hypophthalmichthys molitrix; grass carp Ctenopharyngodon idellus; mullet Liza soiuy; whitefish Erythroculter erythropterus; snake head Ophiocephalus argus; catfish Parasilurus asotus; blunt-headed bream Megalobrama amblycephala, etc. At a water temperature of 10- 27°C, and a water depth of 25-50 cm, the starting velocity of the various kinds of fishes is about 0.2 m/sec. The optimum velocity ranges from a lower limit of 0.3-0.4 m/sec to an upper limit of 0.5-0.8 m/sec. The limiting velocity for the different kinds of fish varies greatly. The upper limit of optimum velocity is generally considered as the preferable velocity for a fishway inlet. The value is about 15-30% less than the limiting velocity. The experiments denote that the current overcoming ability of fish is mainly related to their body shape, body length and the variation of the water temperature. By analyzing the results of the experiments and date from some existing fishways, it was seen that the current overcoming ability of a fish is closely related to its body length. An empirical formula is proposed for estimation purposes.