A bedform morphology hypothesis for spawning areas of Chinese sturgeon |
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Authors: | Hui Zhang Qiwei Wei Hao Du |
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Institution: | (1) College of Fishery, Huazhong Agricultural University, Wuhan, Hubei Province, 430070, China;(2) Key Laboratory of Freshwater Fish Germplasm Resources and Biotechnology, Ministry of Agriculture of China, Yangtze River Fisheries Research Institute, Chinese Academy of Fisheries Science, Jingzhou, Hubei Province, 434000, China;(3) Freshwater Fisheries Research Center, Chinese Academy of Fisheries Science, Wuxi, Jiangsu Province, 214081, China |
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Abstract: | Results from previous research suggested that geomorphic characteristics may be important controlling factors among other
microhabitat variables for spawning fish. We investigated the bedform morphology of seven spawning areas (five historic and
two present spawning areas) of Chinese sturgeon (Acipenser sinensis) by analysis of relief maps of the riverbed and by field surveys. We conclude that the topographic characteristics of the
spawning areas include rocky or gravelly substrate river bend, large variations in water depth and river width and a slope
with moderate length and slope. The turning structure and the adverse slope may be the most important topographic characteristics
for the spawning areas. Combined with the reproductive occurrence of the fish in these spawning areas, we tentatively propose
a bedform morphology hypothesis for the spawning areas. We consider that a spawning area of A. sinensis should consist of three functional areas: Mating area (M), Dispersal area (D) and Incubation area (I). M, D and I are distributed
along the water current and their bedform characteristics are clearly different. M is the place for mature fish to mate and
spawn. It is usually below a riffle with rolling terrain. D is the place for fertilizing and dispersing fertilized eggs. It
is usually in a river bend with sharp variations in terrain, such as deep pools or steep slopes. I is the place for dispersal
of fertilized eggs. It is usually in long point bars or broad shallow areas with rocky substrate. This hypothesis could serve
as a guideline for improving the present spawning areas or constructing new spawning areas, so as to rehabilitate the wild
stock of the sturgeon. |
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Keywords: | Acipenser sinensis Natural reproduction Riverbed topography Microhabitat Yangtze River |
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