Salmon Essay -- essays research papers

The upriver pink-orange migration is atomic number 53 of natures most exciting dramas. only to the five species of Pacific salmon (Chinook , helpmate, coho, pink, and sockeye), it is a long, strenuous, desperate race against time, with each obstacle taking its toll. Pacific salmon belong to a sort called anadromous slant that includes Atlantic salmon, sturgeon, lampreys, shad, herring, sea- run cutthroat trout, and steelhead trout. These species hatch and outlast the first part of their lives in fresh water, then migrate to the naval to spend their adult lives, which may be as short as 6 months or as long as 7 years. When they advert sexual maturity, they return to the freshwater stream of their origin to lay their eggs. Pacific salmon crop the round actuate only once, entirely somewhat Atlantic salmon may repeat the cycle several times. Migration between fresh and salt water occurs during every season of the year, depending on analog and genetic characteristics of t he fish. Groups of fish that migrate to signher are called runs or stocks. pink-orange spawn in virtually all types of freshwater habitat, from intertidal areas to last mountain streams. Pacific salmon may swim hundreds, even thousands, of miles to get back to the stream where they hatched. However, only a small percentage of salmon live to reach their natal stream or spawning grounds. Those males that survive the trip are often gaunt, with grotesquely humped backs, hooked jaws, and battle-torn fins. The females are swollen with a pound or more of eggs. Both have orotund white patches of bruised skin on their backs and sides. Since salmon do not open once they leave the ocean, some testament die on the itinerary because they lack enough stored body fat to fuck off the trip. Many will be caught in fishermens nets. Those that evade the nets may have to swim by dint of polluted waters near cities. Many must make their style over power dams, leaping up from one tiny pussy to t he coterminous along cement stairstep cascades called fish ladders. In the bird feeder streams, waterfalls and rapids are steep and swift enough to eliminate all but the strongest. Otters, eagles, and bears stalk 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 agitating the bottom gravel with her fins and tail, and bending ... ...almon belong to the Department of Commerces interior(a) Marine Fisheries Service. The U.S. Fish and Wildlife Service and other federal and state agencies in like manner have recovery responsibilities. The largest of the Pacific salmon, chinook (Oncorhynchus tshawytscha) average about 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. blue jack salmon (Oncorhynchus kisutch), fourth in Pac ific fishery abundance, is the number one sport 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 get similar migration paths in the Pacific and reach a common lading of about 12 pounds before returning to their natal river to spawn. Pink 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 technical catch. Pink salmon seldom travel more than 150 miles from the express of their natal river.