Illumination Intensity Preference and its effects on feeding efficiency of Juvenile Chinese Sturgeon, Acipenser sinensis Captured from the Estuary of Yangtze River

Habitat preference plays an important role in the life of fish. Illumination intensity preference and its effects on feeding efficiency of juvenile Chinese sturgeon, Acipenser sinensis were studied by Single Factor Experiments．The result shows that the percentage of time spent by Juvenile Chinese sturgeon in dark area(1.4-2.2 lx), transition area(10.4-12.3 lx) and illuminated area (200.2-209.1 lx) are (1.32%±3.50%) , (7.17%±13.5%) and (91.52%±14.9%) respectively; and the number percentage of the fish in three areas are (6.42%±4.13%)，(14.2%±7.45%) and (82.38%±15.2%). Juvenile Chinese sturgeons are photopositive significantly (Kruskal-Wallis Test, P<0.05). The typical behavior of juvenile Chinese sturgeon in the illuminated area is circling movement around the light source. The behavior type is coincident with the mechanism of fish phototaxis of ‘signal-adaption hypothesis’. When provided 206 lx illumination intensity, the feeding consumption(Fc), feeding intensity(Fi) and feeding rate(Fr) of juvenile Chinese sturgeon on Rhinogobius giurinus were (9.67±2.08), (0.97±0.21) and (0.24±0.05). When illumination intensity were 0 lx, the value of Fc, Fi and Fr were (10.67±2.31), (1.07±0.23) and (0.27±0.06). The feeding efficiency of juvenile sturgeons were not significantly different between two illumination conditions(P>0.05, Mann-Whitney Test). The result shows that feeding behavior of juvenile Chinese sturgeon might not be dependent on vision.