The Hokkaido fishery is located at the intersection of the Japanese warm current and the Qiandao cold current. Due to the difference in seawater density, the cold water with high density sinks and the warm water with low density rises, causing vertical agitation of the sea water and bringing the organic matter deposited on the seafloor to the sea surface. The seawater is disturbed, and the flooded seawater brings nutrients to the ocean surface, making plankton prosperous, and then providing abundant bait for fish, and fishery resources are abundant. Hokkaido fishery in Japan mainly produces salmon, pollock, Pacific herring and saury, which is one of the four major fisheries in the world.

The North Sea fishing grounds are located at the confluence of the warm North Atlantic current and the icy waters from the Arctic Ocean going south. Cold and warm ocean currents meet to produce upwelling currents. In the upwelling area, the seawater continuously flows from the lower layer to the surface layer, and the decomposed organic matter and other nutrients in the lower layer of the seawater are also brought to the surface layer. Therefore, the water quality of this sea area is fertile, forming a high-yield fishing area in the North Sea. It is one of the four major fishing grounds in the world, with abundant fish production and various species, mainly herring, mackerel, cod and other fish.

The Newfoundland fishery is located in Canada, in the waters near Newfoundland Island in the Atlantic Ocean, at the intersection of the Gulf of Mexico warm current and the Labrador cold current. Proliferate here. Known as "walking ashore on the backs of cod fish in the water", it is one of the four major fishing grounds in the world.

There is a strong Peruvian cold current on the coast of Peru. Under the prevailing westerly and southeasterly winds, the surface seawater deviates from the coast and the lower layer of cold water overflows. This not only causes the water temperature to drop significantly, but more importantly, it brings a large amount of nutrients such as nitrate and phosphate. In addition, the coast is cloudy and foggy, and the sunshine is not strong, which is conducive to the large-scale reproduction of plankton along the coast. For cold-water fish, In particular, it provides extremely favorable conditions for the reproduction and growth of anchovy (like cold water below 20°C), making it one of the four major fisheries in the world.