池塘养鱼,为近期我国水产的调整重点。池塘养鱼的迅猛发展,带来的一个新问题是:饲料资源的日趋贫乏。这在食用鱼商品率较高的长江中、下游地区尤为突出。一些国营和乡村经营的鱼池、中小型湖泊以及河沟外荡,主要依靠天然饵料,许多靠近湖泊的养殖单位,在湖泊中捞取水草和螺蚬作饲料。这一方面减少了湖泊中鱼类的饲料,影响其生长;另一方面浪费大量的人工及一定的能源,还常常受到天气和季节的制约,造成被动局面。当然也有一些单位种植了部分青饲料;由于品种少,搭配比例不恰当,普遍存在着供需不协 Pond fish, aquaculture for the recent adjustment of China’s key. One of the new problems brought about by the rapid development of fish culture in the ponds is that the feed resources are getting scarcer. This is particularly prominent in the middle and lower reaches of the Yangtze River, where the commodity fish consumption rate is high. Some state-run and rural-operated fish ponds, small and medium-sized lakes, and river ditches depend mainly on natural food supplies and many aquaculture units near the lakes to harvest aquatic plants and snails for feed. On the one hand, it reduces the feed of lakes and fish and affects their growth. On the other hand, it is wasteful of manpower and certain energy and is often restricted by the weather and the seasons, resulting in a passive situation. Of course, some units planted some green fodder; due to a small variety, with the proportion is not appropriate, there is widespread supply and demand