葛洲坝下中华鲟产卵场初次水下视频观察

2007年初次采用水下视频观察了葛洲坝至庙咀江段中华鲟产卵场的河床质及中华鲟受精卵散布和附着状态.根据视频观察的结果,中华鲟产卵场区河床质主要为10～50 cm卵圆或扁圆的卵石排列叠加而成,其表层河床质排列可分为6种模式类型.卵石之间的立方体排列和四面体排列方式为中华鲟受精卵附着提供了2类散布方式.中华鲟受精卵主要散布于冲刷干净的卵石空隙或夹缝中,观察到卵散布区范围约0.25 km2,而被沙粒轻微填塞或掩埋的区域没有发现受精卵,沙粒沉降很可能是限制中华鲟产卵的关键因子之一.视频观察数据对于产卵场模型分析及产卵场改良提供了实证资料.

Underwater Video Observations of the Spawning Ground of Chinese Sturgeon Below the Gezhou Dam

Bottom substrates and the states of the Chinese sturgeon (Acipenser sinensis) eggs adhering to the bottom substrates were first observed with underwater camera in the spawning area of the Chinese sturgeon below the Gezhou Dam. The results show that the bottom substrates of the spawning ground are mainly composed of round or oblate cobbles of 10 to 50 cm in diameter and the arrangement of the surface bottom substrates can be described by six types. The cubical and tetrahedral interspaces of the cobbles provide two common ways for the sturgeon eggs to adhere to or drop in them and the distribution areas of the Chinese sturgeon eggs are estimated as 0.25 km2. The results also show that in the interspaces of the bottom substrates partially or fully filled with sands, no Chinese sturgeon eggs were found, so, the sedimentation of sands may play important roles in the natural reproduction of the Chinese sturgeon. The observation videos will help to validate the bedform morphology hypothesis of the spawning ground of Chinese sturgeon and reconstruct the spawning ground.