Salmon Essay -- essays research papers

The upriver chromatic migration is one of natures most exciting dramas. But to the cinque species of peaceable salmon (Chinook , chum, coho, pink, and sockeye), it is a long, strenuous, desperate race against time, with every obstructer taking its toll. Pacific salmon belong to a group called anadromous fish that includes Atlantic salmon, sturgeon, lampreys, shad, herring, sea- run cutthroat trout, and steelhead trout. These species hatch and harp the first part of their lives in scented water, then migrate to the ocean to croak their adult lives, which may be as short as 6 months or as long as 7 days. When they reach cozy maturity, they evanesce to the freshwater stream of their origin to lay their eggs. Pacific salmon make the round trip only formerly, but some Atlantic salmon may repeat the cycle several times. Migration between fresh and salt water occurs during every season of the year, depending on latitude and contractable characteristics of the fish. Groups of f ish that migrate together atomic number 18 called runs or stocks. Salmon father in virtually all types of freshwater habitat, from intertidal areas to high mound streams. Pacific salmon may swim hundreds, even thousands, of miles to get spinal column to the stream where they hatched. However, only a small percentage of salmon live to reach their natural stream or spawning grounds. Those males that survive the trip are often gaunt, with grotesquely humped backs, hooked jaws, and encounter-torn fins. The females are swollen with a pound or more of eggs. Both reserve large pureness patches of bruised skin on their backs and sides. Since salmon do not feed once they leave the ocean, some will die on the way because they insufficiency enough stored body fat to make the trip. Many will be caught in fishermens nets. Those that evade the nets may have to swim through foul waters near cities. Many must make their way everywhere power dams, leaping up from one tiny pool to the ad joining along cement stairstep cascades called fish ladders. In the tributary streams, water go unders and rapids are steep and swift enough to eliminate all but the strongest. Otters, eagles, and bears prow the salmon in shallow riffles. Once on the spawning grounds, the fish battle each other females against females for places to nest, males against males for available females. The female builds her nest, called a redd, by stir up the bottom gravel with her fins and tail, and bending ... ...almon belong to the Department of Commerces National oceanic Fisheries Service. The U.S. Fish and Wildlife Service and other federal and state agencies also have recovery responsibilities. The largest of the Pacific salmon, chinook (Oncorhynchus tshawytscha) average nigh 24 pounds when they return to their natal river to spawn, most after 2 or 3 years at sea. The chinook is the least abundant of the Pacific salmon. Coho salmon (Oncorhynchus kisutch), fourth in Pacific fishery abundance, is the number one playfulness fish. It spends only one winter at sea, returning the next fall to spawn. It averages about 10 pounds when full grown. Sockeye salmon (Oncorhynchus nerka) make up about 25 percent of the West Coast catch, and chum salmon (Oncorhynchus keta) make up about 13 percent. Both follow mistakable migration paths in the Pacific and reach a common weight of about 12 pounds before returning to their natal river to spawn. wiretap salmon (Oncorhynchus gorbuscha), the smallest of the Pacific salmon, average only about 3 to 5 pounds. However, they make up more than half the total West Coast commercial catch. Pink salmon seldom travel more than 150 miles from the mouth of their natal river.