The characteristics and effect of natural reproductive behavior of Yangtze River sturgeon under the creation of spawning habitat in natural waterbody

<p indent="0mm">Restoring the natural reproduction of Yangtze sturgeon (<italic>Acipenser dabryanus</italic>) is a key and challenging issue in rebuilding its wild population. In March 2023, through the creation of habitat conditions such as water flow and substrates, the Yangtze sturgeon was successfully induced to reproduce in the wild for the first time. Our results revealed that sturgeons exhibited typical reproductive responses to the constructed habitat. As the breeding phase approached, their activities increased, with an average of 1.6 leaps per hour. Before spawning, the sturgeon’s activity was most frequent in the areas of the spawning nest with lower water flow <sc>(0.04–0.36 m/s).</sc> After spawning began, their activity frequency significantly increased in areas with moderate water flow <sc>(0.32–0.60 m/s)</sc> within the nest, and their presence in high-flow areas <sc>(0.1–1.34 m/s)</sc> also became more noticeable. During sperm release, males exhibited rapid tail beats, with a frequency of 232.71±13.74 beats per minute. Females exhibited two types of oviposition movements: one resembling the males’ rapid tail beats but with a lower frequency of 140.38±13.53 beats per minute, and the other involving large and lateral tail movements at a frequency of 105.20±22.25 beats per minute. The participation rate of broodstock in this spawning event reached 75%, with a fertilization rate of 54%. This is the first successful experiment to induce natural spawning behavior in Yangtze sturgeon through environmental regulation in a natural water body, laying the foundation for the restoration and reconstruction of the wild population.