This episode focuses on increasing number of water gates built under the surface of river's water due to the need for water conservancy construction and agriculture irrigation in the 1970s. But water gates affect the fish's migrations and spawning habits, causing the sharp drop of fishery resouces. To solve this problem, fishpasses for fish migration were built along with Jiangsu Dou Long Gang Water Gates. Such practice was soon applied to other places in Jiangsu province.