CATDOLL : CATDOLL: Go to the Hard North Temperate Zone

Go to the Hard North Temperate Zone

Latitude: 66 degrees 34 minutes north latitude to 23 degrees 26 minutes north latitude, that is, between the Tropic of Cancer and the Arctic Circle. Includes most of Asia, Europe, and North America.

The seasonal changes here are obvious, the population is large, and it is affected by polar air masses all year round. Although the surface water temperature is low in winter, the salinity is low, the oxygen content is high, the vertical exchange of water masses is strong, the water is rich in nutrients and plankton is abundant, so a large number of fish that feed on plankton are reproduced and grown, making it an important distribution area of ​​the world's fishing grounds. The number of fish species in this zone is far richer than that in the Arctic zone, mainly Pacific cod, herring, salmon, etc. It plays an important role in the world's fishery economy. Among mammals, there are fur seals, sea donkeys, sea otters, Japanese whales and dolphins in the Pacific; there are Biscay whales, white sea dolphins, seals, etc. in the Atlantic waters. The northern temperate zone will become smaller and smaller! Because the greenhouse effect makes the temperate zone larger, the cold zone also becomes larger!

What type of ocean current is the Peru Current?

The Peru Current, also known as the Humboldt Current, is a compensatory current and the most powerful of the cold currents. It is a low-salinity ocean current that stretches from the southern tip of Chile to the northern Peru along the west coast of South America, flowing from the Antarctic to the equator. At the northern end, it can extend to 1,000 kilometers offshore, and its influence can even reach the Galapagos Islands. It starts from the West Peru Current wind flow at about 45° south latitude, flows northward along the west coast of South America through Chile, Peru, Ecuador and other countries until it reaches the Galapagos Islands in the equatorial sea. The ocean current is 3,700 to 5,500 kilometers long, more than 370 kilometers wide, and has an average flow rate of 0.9 kilometers per hour. In the process of flowing northward, due to the influence of the Coriolis force and the prevailing southerly and southeasterly winds along the coast, the surface seawater deviates westward from the coast, causing the average middle layer of cold water of 100 meters per second to rise to the sea surface, and the seawater temperature is very low. The annual average water temperature is generally 14°~16°C, which is 7°~10°C lower than the surrounding air temperature, making the ocean surface near the coast cloudy and foggy with weak sunshine.

The Peruvian cold current is an important cause of drought in northern Chile, coastal areas of Peru and southern Ecuador: onshore winds are cooled by the cold current and cannot produce precipitation.

The Peruvian Cold Current Large Marine Ecosystem is one of the most important upwelling systems in the world, supporting a large number of marine life. 18%-20% of the world's annual fishery catch comes from this ecosystem. As the upwelling of seawater brings a large amount of nutrients such as nitrates and phosphates, it promotes the proliferation of plankton and provides abundant food for fish. Therefore, the coast of Peru has become one of the world's famous fishing grounds - the Peruvian fishing ground.

Peruvian fisheries

Located on the coast of Peru in the southeastern Pacific Ocean. The Peruvian cold current flowing through the coast of Peru, under the influence of the southeast trade winds and southerly winds and the deflection of the earth's rotation, forms an offshore current of the surface seawater. The lower seawater carries nitrate and phosphate nutrients upwelling, rich in plankton, and abounds in cold-water fish, including anchovies (sardines), bonito, cod, etc. Among them, the output of anchovies ranks first in the world. The annual catch of fish in Peru alone can reach more than 10 million tons, of which 98% are anchovies. It is one of the world's famous large fishing grounds.