历史时期,三峡水域盛产长江上游很多特有鱼类,是世界上最大的淡水鱼类产卵场之一。这么丰富的渔业资源仰赖于以下四大有利自然条件。地形地貌。长江从我国第二级阶梯下降至第三级阶梯时,形成“西控巴渝收万壑,东连荆楚压群山”的壮丽三峡。在亚洲气候区划图上,可看到中亚热带气候区从云贵高原向北方高纬度地区呈犄角状延伸,至三峡后,在北方北亚热带气候区的包围下,三峡形成一个特殊的中亚热带“热岛”。该独特气候与当地陡峡 During the historical period, the Three Gorges area is rich in many endemic fish species in the upper reaches of the Yangtze River and is one of the largest spawning grounds for freshwater fish in the world. Such abundant fishery resources depend on the following four favorable natural conditions. topography. When the Yangtze River fell from the second stage to the third stage in our country, the Yangtze River formed a spectacular “Three Gorges” where the west belts converge and the east meets Jingchu hills. In the zoning map of Asia, we can see that the Central Asian tropical climates extend from the Yunnan-Guizhou Plateau to the northern high latitudes. After the Three Gorges, under the northern subtropical climate zone, the Three Gorges formed a special subtropical “ Heat island ”. This unique climate and local steep gorge