于桥水库的水质保护与渔业生产

WATER QUALITY PROTECTION AND AQUACULTURE IN YUQIAO RESERVOIR

大水面增养殖将水体中的氮、磷、有机物转化成鱼产品,并以渔获物的形式输出水体,从而加大水体氮、磷、有机物的输出量,有减缓水体富营养化、净化饮水水质的作用;同时鱼类的摄食、消化、排泄等新陈代谢活动可加速水中氮、磷等物质循环,使藻类繁衍,如果大量放养草鱼还会导致水草资源破坏、生态失衡,对饮水卫生、安全不利;网箱养鱼投入饲料,直接增加了水源有机污染。围网养殖对局部水域生态平衡有破坏作用,放养密度过大,投入饲料也会直接增加有机污染。库周鱼塘排水会增加水库氮、磷输入量。为保护水库水质和生态平衡,不要盲目往于桥水库中大量投放草鱼,禁止或限制网箱投饵养鱼和围网养殖。同时建议:保护现有鲤、鲫鱼资源,引进能利用腐屑资源的鲴类鱼,加大鲢、鳙放养规格,适度增殖鳜鱼,利用库中水草和库周鱼塘养殖草鱼,防治库中水草对水库水质的二次污染,同时发展了池塘渔业。

The aquaculture can lighten water eutrophication and improve drinking water quality. But on the other hand, the fish metabolism activities as eating, digest and drain can speed up the cycle velocity of the N . P and organic matter in the waters and accelerate reproduction of algae. If a large number of the grass carp ( Ctenopharyngodon iadllus) are put in the reservoir, the fish will destroy the ecological balance and the macrophytes which can improve the drinking water quality. Farming fish in net cases with composite food can increase organic pollution to the reservoir. Farming fish in the waters enclosed with the purse seine can also destroy the local macrophyte and ecological balance. and when a great number of the fish are put in the purse seine, the composite food must be thrown into the purse seine in the later culture period. So farming fish in the purse seine also increases organic pollution by the food to the waters. The waste water discharged from the reservoir-side fishponds may increase N , P to the reservoir. The proposals for how to develop the aquaculture and protect the drinking water quality and ecological balance are as follows: 1 ) A great number of grass carps should not be put blindly in the reservoir ; 2 ) Farming fish in the net case and purse seine should be stopped or limited; 3) The carp ((?)) and crucian carp (Curasstus auratus ) should be protected; 4) The Xenocy prisargenteu Gunther and Plagwnathops microlepis Bleeker) which feed chiefly on decomposed macrophytes should be introduced into the reservoir; 5) Put bigger fingerlings of silver carp (Hypophlh almichthys molitrixi) and bighead carp (Aristichthys nobilis) to the reservoir, and breed the manderin fish (Siniperca chuatsi ) in the reservoir; 6) The grass carp should be farmed in the reservoir-side fishponds with the macrophytes gathered from the reservoir.