长江上游水下光照度的初步调查

2009年1月2日—2月10日,沿长江从上往下选取云南水富码头、四川泸州市合江弥陀镇、重庆江津航道处、宜昌葛洲坝下磨基山四个江段进行了6次不同天气下的水下光照度的测量。水富码头、弥陀镇以及江津航道处三个江段的4次测量,无论天气是阴雨天、阴天、大雾还是晴天,其水下照度在水面下0~1.5 m急剧衰减,在1.5 m处衰减率达到99.5%以上,以后光照度随着水深呈缓慢衰减之势,1.5 m以下至江底的照度基本维持在1.2~8.9 lx。而葛洲坝下磨基山江段的水下照度无论是大雾还是晴天,都呈逐步衰减的态势,在20 m的水底光度衰减率才达到99.9%,维持在9~20 lx。根据调查的数据,从鱼类行为生态学研究与野生鱼类驯养、中华鲟保护及四大家鱼等产漂流性卵鱼类的保护三个方面进行了生态学意义探讨。

Preliminary investigation of underwater illuminance in the upper reaches of Yangtze River

On January 2th to February 10th, 2009, we surveyed the underwater illuminance of four reaches of the Yangtze River for six times in different weather, they were Shuifu wharf of Yunan, Mituo town Hejiang county Luzhou city of Si-chuan, Jiangjin Hydrographic Bureau of Chongqing and Mojishan below the Gezhou Dam of Yichang along Yangtze River. Four surveys in Shuifu wharf, Mituo town and Jiangjin Hydrographic Bureau showed that underwater illumination decayed sharply in water depth from 0m to 1. 5 m regardless of the weather was rainy, cloudy, heavy foggy or sunshiny, with a more then 99. 5% attenuation rate at 1. 5 m depth, and maintained a intensity range from 1. 2 lx to 8. 9 lx from 1. 5 m wa-ter depth to river bottom. While underwater illumination of Mojishan below Gezhou Dam decayed gradually regardless of the weather was heavy foggy or sunshiny, with a 99. 9% attenuation rate at 20 m depth of river bottom, and maintained a in-tensity from 9 lx to 20 lx. According to the survey data, we discussed the ecological significance from following three as-pects: behavioral ecology research and wild fish cultivation, Chinese sturgeon protection and four major Chinese carps and other. floating-egg fish protection.