What are ways in which the sea is harvested for food?

What are ways in which the sea is harvested for food?
Fish from the sea, has been on the staple diet of man for ages. Fishing is one of the oldest occupations known to man. Today many efficient methods are used in fishing to catch fish that inhabit different depths in the ocean. Sonar systems help fishing boats to track shoals of fish. Trawlers haul nets across the seabed, and catch fish, that dwell at the bottom. Drift netting involves hanging a long net curtain across a stretch of sea.

In the long-lining method, fishes are caught on several long fishing lines that are laid out. Fishing boats clean and freeze the fish that is caught. This way, they are able to stay long at sea and supply large quantities to factories. Shellfish, another major seafood, is now raised in farms under the sea, as also seaweed, which is used as food in Japan and China.

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