People have been catching fish from the sea, rivers and lakes for thousands of years. Fishing is still a source of food, and an important industry for many people living near the sea. Japan, China and Russia are the largest commercial fishing nations. The world’s major fishing grounds are the areas of relatively shallow waters that lie above the continental shelf – those parts of the Earth’s landmasses that are submerged by ocean waters.
Most sea fish are caught by fishermen working on trawlers. Trawlers are equipped with a large net that is trawled (dragged) along the sea bed. Distant-water trawlers, the most numerous type, can stay at sea for several months. Many of them have freezers so the fish can be gutted and frozen on board. Middle-water trawlers go out for two or three weeks and near-water trawlers for only a few days at a time.
Trawlers catch demersal fish, those kinds that live near the sea bed. North Atlantic trawlers catch cod in the cold waters off Canada, Greenland and Scandinavia. Japanese and American fleets catch tuna in the deep waters of the Pacific Ocean.
Middle-water trawlers catch fish such as halibut and plaice, while near-water vessels catch fish that live in the warmer waters close to shore, such as haddock, plaice, sole and turbot. These boats do not have freezers on board but the fish can be packed in ice to keep them fresh.
Different techniques are used to catch other marine creatures. Lobsters and crabs are caught in small traps called pots. Oysters and scallops are collected with a dredge, a triangular steel frame with a net on it, which is towed along by a fishing boat.
Today, in many traditional fishing grounds numbers of fish are declining fast, the result of overfishing. In the North Atlantic, herring are now almost extinct and there are far fewer cod and haddock. The use of huge factory ships, on which large quantities of fish can be frozen, is severely depleting supplies for local people in developing countries, who rely on fish for their livelihood. There is also concern about the destruction of ocean food chains by overfishing. It is estimated that 20 million tonnes of fish a year are discarded by fishing boats because they are not the right kind – a practice that needlessly reduces stocks of other kinds of fish.
TRADITIONAL FISHING
In some parts of the world, fishermen still go out in small boats and catch fish with hand-held nets, as they have done for centuries. These fishermen catch only enough fish for their local communities.
Whales used to be hunted for their meat and oil. Harpoons and factory ships were used. So many species became endangered that commercial whaling of a number of different species was banned by international agreement in 1986.
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