The reasons for the formation of fisheries, the conditions for the formation of fisheries

The world's four largest fishing grounds.

Respectively, the North Sea Fisheries (Western Europe.

Newfoundland Fisheries (Canada), Peru.

Fishing grounds (Peru), Hokkaido fishing grounds (Japan).

There are generally two reasons for the formation of fishing grounds, one is the convergence of cold and warm currents, where the environment of the water changes, where fish gather, and the cold and warm currents converge, stirring the seawater, bringing the bottom nutrients to the surface and becoming bait. For example, the Hokkaido fishing grounds are located in the Japanese Warm Current.

confluence with the cold current of the Kuril Islands; The Newfoundland Fishery is located at the confluence of the Mexican Warm Current and the Cold Labrador Current; The North Sea fishery is located at the confluence of the North Atlantic Warm Current and the East Greenland Cold.

Another reason is the influence of upwelling. Peruvian fisheries are affected by the southeast trade winds, which blow from the shore to the Pacific Ocean, causing the sea water on the shore to continue to decrease, and the nutrient-rich sea water at the bottom is replenished and used as bait to collect fish.

In his analysis of the causes of fishing grounds in Newfoundland and Hokkaido, Japan, he said, "It is related to the convergence of cold and warm currents, which brings a variety of bait to fish. "When reviewing the knowledge of fishing grounds, it is necessary to synthesize the relevant narratives of geography in junior and senior high schools in order to make a comprehensive and systematic analysis

The conditions for the formation of fishery grounds can be summarized as follows:

How are fisheries formed?

1) The formation of fishing grounds on the continental shelf can be analyzed from three aspects:

The sea water of the continental shelf is shallow, and the solar radiation heat energy reaches the seabed, which is conducive to the reproduction and growth of fish bait (plankton);

The bottom of the continental shelf is deposited with sediment brought by the continent, which is conducive to fish spawning.

The continental shelf is contiguous to the continent, and the various organic matter brought by the rivers flowing from the continent provides nourishment for fish and plankton.

2) The convergence of cold and warm currents to form a fishing ground is mainly analyzed from two aspects:

In the sea where cold and warm currents meet, the sea water is prone to agitation, and the nutrients from the lower layer are flooded to the upper layer, which is conducive to the growth of plankton and attracts a large number of fish.

In the sea area where the cold and warm currents meet, there are often cold-water and warm-water fish that come with the cold and warm currents to stay here (the fish are not used to the nature of the oncoming currents and do not dare to move on), so the fish gather and form a large fishing ground. For example, the world-famous fishing grounds in Hokkaido, Newfoundland and Zhoushan in China have this condition.

The reason for the formation of the fishery is that there is a large amount of plankton, which provides a lot of food for the fish, attracts a large number of fish to feed, and forms the fishing ground.

Conditions for the formation of fishing grounds: 1. At the confluence of cold and warm currents. It is conducive to plankton blooms and provides bait for fish.

2. Sea area with upwelling compensation current. 3. In the coastal continental shelf waters. 4. Near the mouth of the river.

5. It belongs to the temperate sea area.

Fishery refers to the waters with fishing value where fish or other aquatic economic animals pass through or swim intensively, and with the changes in environmental conditions such as spawning and breeding, feeding and fattening or wintering temperature, they gather in groups in a certain season to swim through or stay in a certain water area and form a relatively concentrated place with fishing value in fishery production.

The world's four major fishing grounds: North Sea Fisheries, Newfoundland Fisheries, Hokkaido Fisheries and Peruvian Fisheries, the first three are formed by the cold and warm currents after the cold and warm currents meet, and the rich materials on the seabed tumble up, forming the Peruvian fishing grounds are upwellings, which belong to the vertical compensation flow.

There are various types of fishery divisions. Generally, according to the distance between the fishery and the fishery base, the depth of the fishery, the geographical location, the environmental factors, the habitat distribution of fish at different stages of life, the operation mode and the fishing object.

Distribution of the world's fishing grounds and their causes.

Temperate coastal continental shelf fisheries (the part of the continental seabed that extends from the coast to a depth of about 200 meters underwater) Causes:

1.The continental shelf has shallow waters, concentrated sunlight, strong biological photosynthesis, and abundant plankton. 2.Rivers that flow into the sea bring abundant nutrients that feed fish and plankton.

3.In the temperate zone, the surface sea water and the bottom sea water are exchanged in winter, and the upper sea water is rich in nutrients, which is conducive to the reproduction of plankton.

From the perspective of the impact of ocean currents on fishing grounds, there are four major fishing grounds in the world: 1. Hokkaido fishing grounds are formed by the confluence of the warm current of Japan and the cold current of the Kuril Islands.

2. The Newfoundland Fishery is formed by the confluence of the warm Gulf Current and the cold current of Labrador. 3. The North Sea Fishery is formed by the confluence of the warm current of the North Atlantic Ocean and the cold water of the Arctic Ocean to the south. 4. Peruvian fisheries are formed by rising compensating currents along the Peruvian coast.

Due to the difference in the density of cold and warm seawater, the seawater is stirred, so that the nutrients in the lower layer reach the surface of the seawater, which is conducive to the reproduction of plankton, and then provides sufficient bait for fish, forming a world-famous large fishing ground. The cold current in Peru is due to the influence of the southeast trade winds along the coast of Peru, the surface sea water flows northward under the action of the wind, and the sea water flowing away from the original sea area is replenished by the deep sea water, which turns upside down, bringing rich nutrients on the seabed, and plankton multiplies in large quantities, providing sufficient bait for fish and shrimp to form a large fishing ground. (Upcompensating Flow).

Summary. 1. There is sufficient sunlight and sediment (1) Fishing grounds are usually mainly concentrated in the temperate continental shelf waters, because the sea water of the temperate continental shelf is relatively shallow, so solar radiation can irradiate the seabed, so that plankton can better reproduce and grow, so as to provide enough bait for fish to attract fish to gather. (2) Because the continental shelf is connected to the continental shelf, sediment, various organic matter and other substances will enter the continental shelf, which is conducive to the spawning and development of fish.

2. The intersection of cold and warm currents (1) In temperate areas, there is a situation where cold currents and warm currents meet, in winter, when the surface sea water and the bottom sea water are exchanged, the bottom sea water will be flooded, because it contains rich nutrients, so that phytoplankton can grow better, so that fish are gathered. (2) In addition, cold currents can attract fish of different natures to stay here, and then the area will be formed by the aggregation of fish.

1. There is sufficient sunlight and sediment (1) Fishing grounds are usually mainly concentrated in the temperate continental shelf waters, because the sea water of the temperate continental shelf is relatively shallow, so the solar radiation can be enough to irradiate the seabed, so that plankton can better reproduce and grow, so as to provide enough bait for fish to attract fish to gather. (2) Because the continental shelf is connected to the continental shelf, sediment, various organic matter and other substances will enter the continental shelf, which is conducive to the spawning and development of fish. 2. The intersection of cold current and warm current (1) In the temperate zone, there is a situation where the cold current and the warm current meet, in winter, when the surface sea water of the cave balance and the bottom sea water are exchanged, the bottom sea water will be flooded, because it contains rich nutrients, so that phytoplankton can grow better, so that the fish are gathered.

(2) In addition, cold currents can attract fish of different natures to stay here, and then the area will be formed by the aggregation of fish.

I'm still a little confused, can you be more detailed?

3. In areas where cold sea water is flooded, bait is usually more abundant, which will cause fish to gather, and then form a fishing ground.

Reasons for the formation of the fishing grounds: The Hokkaido fishing grounds are formed by the confluence of the warm current of Japan and the cold current of the Kuril Islands; The Newfoundland fishery is formed by the confluence of the warm Gulf Current and the cold Labrador Current; The North Sea fishery is formed by the confluence of the North Atlantic Warm Current and the East Greenland Cold Current; Peruvian fishing grounds are formed by upwelling compensating currents along the Peruvian coast. Reasons for the formation of fisheries:

The Hokkaido Fishing Ground was formed by the confluence of the Japanese Warm Current and the Kuril Cold Current'；The Newfoundland fishery is formed by the confluence of the warm Gulf Current and the cold Labrador Current; The North Sea fishery is formed by the confluence of the North Atlantic Warm Current and the East Greenland Cold Current; Peruvian fishing grounds are formed by upwelling compensating currents along the Peruvian coast.

The confluence of cold and warm currents disturbs the seawater, and the upper seawater brings nutrients to the surface of the ocean, so that plankton can flourish, and then provide abundant bait for fish, and fishery resources are abundant. In addition, the confluence of cold and warm currents can create "water barriers" that prevent fish from swimming, and for these reasons large fishing grounds can be formed.

1. Peruvian fishing grounds are formed by upwelling.

2. The North Sea fishery is formed by the confluence of the North Atlantic Warm Current and the East Greenland Current.

3. The Hokkaido fishing grounds are formed by the confluence of the warm current of Japan and the cold current of the Kuril Islands.

4. The Newfoundland fishery was formed by the confluence of the warm Gulf Current and the cold Labrador Current.

That is, only the Peruvian fishery is formed by the upwelling, and the other three are formed by the convergence of cold and warm currents!

1. Rivers input a lot of nutrients.

2. The water area is shallow, under the action of wind, waves, tides and convection, the water body is fully mixed, the bottom layer is supplemented to the upper layer, and the whole water body is well nourished.

3. Photosynthesis is sufficient, and phytoplankton multiplies in large quantities.

4. The water area is shallow, so the material circulation is fast and the primary productivity is high.

5. Due to the abundance of bait organisms, the continental shelf is generally a spawning ground, and the bay is also a fattening place for fish.

6. The water depth of the continental shelf is suitable, and the seabed is relatively flat, which is suitable for fishing gear operations.

7. At the edge of the continental shelf, due to the offshore action of the upper current, the water in the lower layer of the open sea is introduced, resulting in upwelling.

8. In the sea area near the edge of the continental shelf, coastal water systems and open sea systems generate coastal fronts.