Spatial distribution and habitat suitability indices for non-spawning and spawning adult Chinese sturgeons...-长江水产研究所 长江水产研究所

Spatial distribution and habitat suitability indices for non-spawning and spawning adult Chinese sturgeons...

Summary:The study objectives were to identify the horizontal and vertical distributions of adult Chinese sturgeon Acipenser sinensis in relation to the Habitat Suitability Index (HSI) in order to assess the utility of the only remaining spawning grounds by adults and to understand the effects of river alterations on habitat use. Twenty-five adults were surgically implanted with ultrasonic transmitters and located by mobile tracking and fixed monitoring stations during the 2006–2009 spawning seasons. Fish locations and depths along with water depth and bottom characteristics (topography, velocity, and embeddedness) were measured during tracking and used to determine HSI curves for non-spawning and spawning adults. Most fish locations (91%) were on the spawning grounds (GZD to Miaozui reaches). Horizontal distribution differed before and after spawning, among years, and between the sexes. Adults used deeper depths during the day than at night (P < 0.001), while also preferring shallower depths on the day of spawning rather than the days before and after. Mature females used deeper water than other females (P < 0.001). Comparison of horizontal and vertical distributions before and after river alterations found fewer adults using the grounds impacted by a diversion dike which was built on the spawning grounds. Adults also used shallower depths after the Three Gorges Dam regulated river flow over the spawning grounds. The HSI model and the use of Weighed Usable Areas (WUA) for mature and immature adults indicated suitable habitat was available, but was reduced by the river alterations resulting in reduced spawning success and placing the population into a situation close to extirpation.

其它信息:C. Wang, B. Kynard, Q. Wei, H. Du, H. Zhang.J. Appl. Ichthyol. 29 (2013), 31–40