There are many spawning grounds and feeding grounds for economic fish and shrimp. The hairtail fishing ground with the largest scale and the most output in winter along the coast of China is a good area for bottom trawling and has become the most famous fishing ground in China. The important types of operation in this sea area are light purse seine, gill net and sail net.
Zhoushan Fishing Ground is the largest offshore fishing ground in China, which is as famous as Kuril Islands Fishing Ground in the Soviet Union, Newfoundland Fishing Ground in Canada and Peru Fishing Ground in Peru. Fishermen used to divide Zhoushan fishing ground into Dakun fishing ground, Shengshan fishing ground, Langgang fishing ground, Huang Ze fishing ground, Daiqu fishing ground, Zhongjieshan fishing ground, Yang 'an fishing ground and Jintang fishing ground.
Zhoushan fishing ground has been a common fishing ground for coastal fishermen since its development. Since liberation, the number of fishing boats in Zhejiang, Jiangsu, Fujian and Shanghai (referred to as "three provinces and one city") has been increasing, and some fishing boats from Liaoning, Hebei, Shandong, Tianjin and other provinces and cities have also come to Zhoushan Fishing Ground for fishing. In the 1960s and 1970s, fishing boats gathered in Shengshan Fishing Ground to catch hairtail in winter. At the peak of flood season, there were 6,543,800 fishing boats and 6,543,800 fishermen.
The central base of the fishing ground is located in the holy mountain. Influenced by the confluence of warm current in Taiwan Province Province and cold current in Japan, the fishing ground is rich in bait, which provides a good material environment for local aquatic animals. Zhoushan Fishing Ground is located in the north of the East China Sea and the southeast of the Yangtze River estuary, outside the Qiantang River estuary and in the south of the Yangtze River estuary, with a range of 29° 30ˊ~ 365° 438+0 00ˊN 00ˊ N, 65 438+0 2500 ˊ E and an area of about 14350 square nautical miles.
Zhoushan Fishing Ground is located in the east of Zhouwai Fishing Ground, connected to Yushan Fishing Ground in the south and the Yangtze River Estuary Fishing Ground in the north, covering an area of about 53,000 square kilometers. The seabed is mainly composed of fine-grained sedimentary mixtures such as silty ooze and clayey ooze, which is an integral part of the continental shelf of the East China Sea. The water depth is generally 20 ~ 40 meters. The north-south 80-meter isobath is 280 ~150km wide from the shore.
Zhoushan Fishing Ground is located at the confluence of the estuaries of the Yangtze River, Qiantang River and Yongjiang River, the coastal current, the warm current of Taiwan Province Province and the cold water mass of the Yellow Sea. On the mainland, the average annual discharge of the Liujing River into the sea is nearly 1 trillion cubic meters, forming a powerful low-salt water mass, with turbid water color, extending outward in spring and summer and retreating to the coast in autumn and winter. The warm current in Taiwan Province Province is hot and salty, and the water is clear. Wedge from south to north in spring and summer, reaching the coastal waters, deviating from the coast in winter and retreating to the south. The Yellow Sea cold water mass moves south. With the change of warm current intensity in Taiwan Province Province, it extends into the fishing ground like the tip of the tongue in autumn and winter, and gradually recedes northward in early summer, forming a mixed zone of north and south water masses. The tidal current of fishing ground belongs to the regular semidiurnal tidal area, and the peripheral islands are connected with the eastern sea area, and the flow direction is clockwise. The western sea area and islands are arranged, and the reciprocating flow is prominent. The average monthly water temperature in fishing ground is 28℃ ~ 29℃ in summer and below 8℃ in winter. The salinity of fishing grounds in the outer sea area is 29 ~ 34 ‰. The inner sea area is greatly influenced by continental current, which is low in summer and high in winter.