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Fisheries

Introduction

Lobster fishing off the coast of Cape Breton

Fisheries - industry of harvesting fish, shellfish, and other aquatic animals. Fisheries may be large commercial fisheries, recreational fisheries, or small subsistence fisheries (fishing to provide the basic needs of the fishing community). The term fishery is also used to describe the waters where fishing takes place or the species of fish being harvested, such as the Alaska halibut fishery. Fisheries include familiar finned fish species, like cod and flounder; mollusks, including oysters and squid; and crustaceans, such as shrimp and crabs. Lesser-known fisheries include echinoderms, like sea urchins; some amphibians, including frogs; and cnidarians, such as jellyfish. Even the harvest of whales is usually considered a fishery.

Fisheries are an important source of food, income, jobs, and recreation for people around the world. This is particularly true in island nations, such as Japan and Iceland, where seafood is eaten as a major source of protein. The average person in Iceland eats nearly 90 kg (200 lb) of fish per year, more than six times the worldwide average.

Worldwide harvest of fishery products has steadily increased to meet the growing global demand for seafood. In 2001 an estimated 130 million metric tons of fishery products were harvested. China was responsible for the largest harvest, followed by Peru, Japan, India, Chile, the United States, Indonesia, and Russia.

The increasing demand for seafood has led to a complex, global system of trade in fisheries products. Japan is the largest importer, followed by the United States, France, Spain, and Germany. Thailand is the largest exporter, followed by the United States, Norway, China, and Denmark. The United States imports large quantities of high-valued fishery products, such as shrimp and lobster, and exports products not as popular among American consumers, such as salmon roe (eggs) and sea urchin roe, which are exported to Japan.

Today scientists consider many fisheries to be fished beyond the capacity of the resource. Current harvest rates are thought to be unsustainable - that is, unable to be maintained year after year without depletion of the fish stock. Experts believe that increases in world fish supply will require better management of the resources as well as the increased use of fish farming or aquaculture.

Major Fisheries

The range of fisheries is immense-over 4,000 aquatic species are harvested worldwide. The shrimp fishery alone includes well over 40 species. Fisheries are located almost anywhere there is water-from the brine shrimp fishery in the Great Salt Lake of Utah in the United States, to the North Pacific Ocean where salmon, pollock, king crab, halibut, and many other species are caught. Over 80 percent of the world's fisheries are located in the coastal and ocean environment, and nearly 20 percent are found in inland fresh water fisheries. Currently, over half of the world's fishery harvests come from the Pacific Ocean; 25 percent are from the North Pacific alone.

The largest fisheries group is made up of small, pelagic (open ocean) fishes such as herring, sardine, anchovy, and related species. Over 20 percent of the world's fishery harvest comes from this group, and Chile and Peru are the leading harvesters. These fish have relatively low commercial value and are often used to make feed for poultry, hogs, and other animals.

The winter flounder, also called lemon sole, belongs to a group of marine fish known as flatfish, characterized by a flattened body with both eyes on the same side of the head. The winter flounder has the ability to change its body coloration to match that of the immediate background making it well adapted for a bottom-dwelling existence. Flounder is valued for its mild flavor and lean, firm flesh.

Another large category of harvested fishes, accounting for nearly 10 percent of the world's fishery harvest, is the groundfish, or demersal fish, that live near the ocean floor. These generally white-fleshed fishes include cod, haddock, pollock, and hake. Cod and haddock tend to be relatively high in commercial value. The Alaskan pollock is less valuable and is often used in the fish sandwiches sold at fast-food restaurants. Also in the groundfish group are flatfish, such as flounder, halibut, and sole, which live directly on the ocean bottom. This well-known group of fish usually has a high commercial value but accounts for less than 1 percent of world harvest.

The black marlin is the largest member of the Istiophoridae family, which includes sailfish and spearfish. It grows to a maximum weight of about 630 kg (1,400 lbs). The black marlin is a popular game fish found in the Pacific Ocean.

Skipjack Tuna

Fish such as tuna, swordfish, marlin, and mahi-mahi make up the large pelagic fish category and account for nearly 5 percent of world harvest. Tuna is consumed fresh in great quantities in Japan and sold canned around the world. Canned tuna is the fish eaten most often in the United States.

Once one of the most common species of salmon in the Pacific Northwest, the Coho have been diminished to 5 to 10 percent of their former population by a combination of overfishing, habitat destruction, and the erection of a series of dams. They are now dependent on state and federal fish hatcheries to sustain their numbers.

Coho salmon

Salmon belong to the anadromous group, meaning they lay their eggs in fresh water but usually spend their adult lives in the ocean. Although the salmon fishery only accounts for about 2 percent of world fishery harvests, it is one of the most important wild fisheries in Canada, Japan, Russia, and the United States (especially to the fishery industry in the state of Alaska). Salmon are also cultured in farms in many countries, including Australia, Chile, Canada, Norway, Scotland, and the United States. Some species of salmon are also highly prized sport fish.

The channel catfish is a commercially important food fish. Its tasty flesh has been compared to black bass. Originally found in freshwater streams and lakes in central and eastern parts of the United States and southern Canada, channel catfish have been introduced widely throughout the United States. Catfish farming, or raising catfish commercially in large ponds, is expanding rapidly in the southeastern United States.

Several freshwater fisheries are also important. Carp and related freshwater fish are consumed mostly in Asia and parts of Europe. Carp are generally raised in ponds and account for nearly 10 percent of all fish harvested worldwide. In the Southern United States, the farm-raised catfish industry grew rapidly from a cottage industry in the 1970s to the largest aquaculture industry in the United States in the 1990s. The tilapia, a freshwater or brackish water (mixture of fresh and saltwater) fish native to Africa, is now being raised globally to add protein to the diets of people in less-developed areas-especially in Asia and South America. It is also being sold to meet the growing demand for seafood in countries such as the United States. Tilapia harvests make up a relatively small percentage of the global fish supply, but production is still increasing.

The spot prawn is commercially harvested in the northeast Pacific ocean from southern Alaska to southern California. Popular for cooking, the spot prawn has a sweet, delicate flavor and a firm texture.

Shrimp

Shrimp are harvested worldwide. Most large- and medium-sized shrimp come from the tropical waters of countries like Thailand, India, Ecuador, and Mexico. Many small shrimp are harvested from the cold waters of Iceland, Greenland, and Canada. Today, cultured or farmed marine shrimp play an important role in supplying the world's shrimp demand. Total wild and farmed shrimp harvest accounts for less than 5 percent of the total world fisheries harvest. Even so, shrimp has a very high commercial value and is the most important species group in world fisheries trade. The United States spends more on shrimp purchased from around the world than on any other imported fishery product.

From the appearance of its small body and long, jointed legs, it is easy to understand how the spider crab got its name. All spider crabs are decapods, having ten legs. Each of the first two legs has a moderately large sharp claw. Found in nearly all oceans and seas, the spider crabs range in leg span from a few centimeters to nearly 4 m (13 ft). Many of the larger species are edible.

Other important fisheries include scallops harvested from Japan, Canada, China, and the United States; king crab from Alaska and Russia; clawed lobster from Canada and the United States; and spiny lobster, squid, and octopus from around the world.

Fishing Methods

Fishing for anchovies

The methods used for catching fish are nearly as diverse as the fisheries themselves. For over a thousand years, fisheries in parts of Japan have used trained cormorants (sea birds) to harvest small fish. Elsewhere, sport fishermen use hand-tied, artificial flies to catch trout. Scuba divers harvest abalone and ornamental reef fish. In the United States, harpoons are still used to harvest some bluefin tuna.

The net, however, is the most common type of fishing equipment. Various kinds of nets are used for different kinds of fish. Seine nets encircle entire schools of fish and are used to harvest tuna, salmon, anchovies, and menhaden. Trawl nets are usually shaped somewhat like a cone and are towed behind fishing boats to catch cod, flounder, and shrimp. Gill nets are made with openings that are just large enough for the head of the fish to pass through, hooking the gills into the mesh. This method is often used to catch salmon and herring. Fish traps use nets as underwater fences to guide fish into a holding area from which they cannot exit. This method is particularly useful if the fish are to be sold live.

Dredges and dredge nets use a metal frame at the mouth of a net that is dragged along the bottom. This type of gear is used to harvest scallops and oysters. Crab and lobster are generally caught using baited cages called pots. Some octopus fisheries use clay pots into which the octopus enters instinctively when looking for a hiding place.

Variations of the rod and reel method are used in both recreational and commercial fisheries. They are used in trolling (trailing a baited line behind a moving boat) for high-valued species, such as bluefin tuna and chinook salmon. Longlines are long, heavy ropes attached to lines with baited hooks. They can extend for several kilometers and are attached to moored buoys or trolled from vessels. Longlines are used to catch halibut, swordfish, shark, and cod.

In the 1950s large-scale commercial fishing, known as industrialized fisheries, began to exploit increasingly larger areas of the oceans. Industrialized fisheries used improved fishing vessels, including factory ships that could process fish catches at sea, and fish-finding equipment that included sonar and even airplanes for spotting schools of fish, making it easier than ever to find the target fish. In the 1980s the global positioning system began to be used so that fishing vessels could return to precise locations where fish were found. Improved nets and other fishing gear also greatly improved the efficiency of harvests. The use of these improved methods led to intense pressure on fish stocks, resulting in the potential depletion of many fisheries.

Depletion Of Fish Stocks

The increasing global demand for fish over the past several decades has increased the pressure to harvest more and more fish. In the 1970s, most nations enacted laws to protect a 300-km (200-mi) ocean zone along their own coastlines. In the United States and many other places, this eventually resulted in the prohibition of foreign fishing vessels within these protected boundaries. However, in most cases, rather than limiting the amount of fishing, this measure has caused fishing to increase as domestic fishing vessels replaced the foreign fleets. Fishing effort has been consistently increasing for several decades, resulting in world harvests more than 300 percent above 1950 harvest levels.

In 1992 a decline in the cod supply led the Canadian government to impose a ban on cod fishing off the coast of Newfoundland and Labrador. The ban instantly eliminated thousands of jobs, but enabled the cod stocks to rebound. In 1997 Canada reopened the waters to cod fishing on a limited basis. Toronto Sun reporter David Kendall explores the devastating economic effects of the ban on the coastal communities of Newfoundland and Labrador.

This increased harvest has had major consequences. Scientists at the Food and Agriculture Organization of the United Nations (UN) consider over one-third of the world's top 200 marine fisheries to be in a state of decline. Some of the fisheries in decline include swordfish, bluefin tuna, red snapper, many flatfish species, and Atlantic cod. Furthermore, as popular fish stocks become depleted, harvesters begin to fish more actively for other seafood, such as mackerel, Pacific whiting, and squid. Because the marine ecosystem is complex and involves the interaction of many species, some scientists are concerned that more-intensive fishing in lower niches of the marine food chain may inhibit the recovery of popular fish stocks. This is because the popular fish may depend on these fish for food. On the other hand, the substitute fish and the popular fish may compete for the same food or habitat. In this case, harvesting the substitute fish may help the recovery of the popular fish species.

Anderson, James L. "Fisheries." Microsoft® Student 2007 [DVD]. Redmond, WA: Microsoft Corporation, 2006.