汉江中游产漂流性卵鱼类产卵场的现状

Current status of spawning grounds of fish with pelagic eggs in the middle reaches of Hanjiang River

于2004年5—8月对汉江中游江段产漂流性卵鱼类产卵场的现状进行了调查。结果表明：汉江中游现有产漂流性卵的鱼类16种，其中经济鱼类仅有草鱼Ctenopharyngodon idellus 、青鱼Mylopharyngodon plceus、鲢Hypophthalmichthys rnolitrix、鳙Aristichthys nobilis、长春鳊Parabramis pekinenzis、赤眼鳟Squaliobarbus curdculus螂等8种；产漂流性卵鱼类产卵和产卵的规模与江水的温度、流量、流速、涨水持续的时间紧密相关；汉江中游干流和支流唐白河共有11个经济鱼类产卵场，20个小型鱼类产卵场；干流鱼类产漂流性卵1632651万粒，“四大家鱼”、其它经济鱼类和小型鱼类分别占0．57％、2．23％和97．20％；支流唐白河鱼类产漂流性卵52985万粒，“四大家鱼”、其它经济鱼类、小型鱼类分别占0、14．15％和85．85％。与20世纪70年代相比，产漂流性卵鱼类种类减少9种，全部为经济鱼类；汉江中游干流产卵量增加2．59倍，支流唐白河的产卵量减少76．17％；“四大家鱼”和其它经济鱼类分别减少89．97％和80．17％；干流王甫洲和襄樊的2个重要经济鱼类产卵场与支流唐白河12种经济鱼类的产卵场消失，而小型鱼类产卵量增加9．48倍。汉江中游经济鱼类资源呈衰退趋势。

A survey on a status of spawning ground of fish with pelagic eggs was carried out in the middle reaches of Hanjiang River from May to August in 2004. It was found that there were 16 species of fish with pelagic eggs including some commercial fishes such as grass carp Ctenopharyngodon idellus, black carp Mylopharyngodon piceus, silver carp Hypophthalmichthys molitrix （ Cuvieret Valenciennes）, bighead carp Aristichthys nobilis （ Richardson）, bream Parabramis pekinensis （ Basilewsky）, and Squaliobarbus curriculus （Richardson） in the middle reaches of Hanjiang River. Temperature, discharge, current velocity, and period when freshet maintains in the river significantly impacted reproduction and fecundity of the fish. Both 11 spawning sites of commercial fish with floating eggs and 20 spawning sites of small fish was found in the middle reaches of Hanjiang River and one of its tributaries - Tangbai River. There were 0. 57% of four major Chinese carps, the 2. 23% of other commercial fishes and the 97.2% of small fish in 16. 326 billion of pelagic eggs in the mainstream of Hanjiang River. Meanwhile, there were the 0 of four major Chinese carps,the 14. 15% of other commercial fish and the 85.85% of small fish in its tributaries - Tangbai River. In comparison with the data in 1970s, the fish with pelagic eggs decreased by 9 species, all of which belonged to commercial fish species. The number of the fish eggs in the middle reaches of Hanjiang River increased by 2. 59 times, but the total eggs in its tributaries - Tangbai River decreased by 76. 17%. The four major Chinese carps decreased by 89.97% ,and other commercial fish decreased by 80. 17%. Two important spawning sites of the commercial fish situated in Wangfuzhou and Xiangfan in the mainstream of Hanjiang River and 12 species of commercial fish in the tributaries - Tangbai River were disappeared, but the egg number of the small fish increased by 9.48 times.