我国幅员辽阔,南北跨度大。由于南北纬度相差的较多,对于同一个种类生物生长在不同的纬度地区,结果就会有很大的差别,河蟹就是这样的一个品种。成蟹(商品蟹)是由扣蟹经一年的生长达到的。下面就以其生长的过程看南北方的不同结果。南方的长江流域,扣蟹经一年的生长,达到成蟹规 Our country has a vast territory and a large span of north and south. Because of the difference between north and south latitudes, for the same species of biological growth in different latitudes, the result will be very different, crab is one such species. Crab (commercial crab) is achieved by crabs growing by one year. Following the process of its growth to see the different results of North and South. The Yangtze River in the south, buckle crabs after a year of growth, to become crab rules