Substrate color preference and feeding by juvenile Chinese sturgeon Acipenser sinensis

What is it about?

Experiments were conducted in artificial stream tanks with juvenile Chinese sturgeon, Acipenser sinensis, captured in the Yangtze Estuary to test two null hypotheses (1) juveniles have no preference for white or black substrates, and (2) white or black substrate color has no effect on juvenile feeding efficiency on the barcheek goby,Rhinogobius giurinus, a dark-colored prey of wild juveniles. Juveniles strongly preferred white substrate. However, in feeding tests, feeding efficiency by juveniles was similar on white or black substrates. Thus, substrate color had no effect on feeding efficiency. Results suggest the innate preference for white substrate is not a visual adaptation for capturing prey on a contrasting background, but is an adaptation predisposing juveniles to seek light-colored sandy substrate where forage abundance is greatest.

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Why is it important?

Chinese sturgeon, Acipenser sinensis (Gray, 1835), is an anadromous species that only spawns in the Yangtze (=Changjiang) River of China. Adults migrate in coastal waters for years before returning to the Yangtze River to spawn from mid-October to early November. As a result of damming and overfishing, the population of A. sinensis has greatly declined in abundance. The species is classified as endangered by national and international agencies: the Chinese government , the world wildlife trade convention appendix II protected species (CITES), and in 2010, the International Union for Conservation of Nature (IUCN) upgraded the species to critically endangered (CR) status. Understanding habitat preference of rare and endangered animals is critical to improved management and conservation. In order to understand the environmental factors important to feeding and habitat preference of juveniles, two null hypotheses were tested: (1) juveniles have no preference for white vs. black substrate colors, and (2) substrate color (white or black) has no effect on feeding efficiency of juveniles on a common prey, the dark-bodied barcheek goby,Rhinogobius giurinus.