Saving salmon why care? Dams serve vital human needs but may harm salmon. Should dams be busted to save a fish? (Life Cycle/Rivers).AFTER YEARS on their own, some animals will do anything to get back home. For several years, the Years, The the seven decades of Eleanor Pargiter’s life. [Br. Lit.: Benét, 1109] See : Time chinook Chinook, indigenous people of North America Chinook (shĭn  k`, chĭ–), Native American tribe of the Penutian linguistic stock. (or king) salmon roams the open
Pacific Ocean, where it feasts on crustaceans, squid, and smaller fish,
growing from a smolt smoltyoung salmon on its way downriver en route to the sea; covered with distinctive silvery scales. (juvenile) to an often 60-pound adult. Then it swims up to 3,300 kilometers (2,000 miles) back to its exact birthplace--a mountain stream in the U.S. Pacific Northwest. It migrates day and night without sleeping or eating, living off stored protein and fat. Its sole mission: to find its home stream to mate and spawn, or leave behind eggs that hatch the next salmon generation. As the chinook courses up the Columbia and Snake rivers (see map, above), it leaps and thrashes against rushing currents, even hurling itself over cascading waterfalls. How does a salmon find its way home? By its nose: Water flows in through one of two olfactory pits (nostrils not connected to the throat) and flows out the other. Odors in water stimulate its sensitive olfactory receptors (scent cells), which trigger the brain to analyze smells. And the chinook noses out the scent of the native stream it left years ago! [ILLUSTRATION OMITTED] But over the last century, humans have built massive dams that have transformed the Columbia River Basin. Dams help churn out the bulk of the region's electricity, prevent floods, create artificial lakes for boating and fishing, and irrigate ir·ri·gate v. To wash out a cavity or wound with a fluid. land for Idaho potatoes and Washington apples, among other crops. But dams invariably in·var·i·a·ble adj. Not changing or subject to change; constant. in·var  i·a·bil disrupt the
natural migration patterns of Pacific salmon, and since the completion
of more dams in the 1960s and '70s, salmon populations have steeply
declined--some species are already extinct. Now a heated debate rages:
Should dams be busted, or partly torn down, to meet the needs of salmon?
Or do human needs outweigh any concern for saving salmon?Q: WHAT'S SO IMPORTANT ABOUT SALMON? Salmon are a valuable and healthy food source for millions of people, providing protein, essential fatty acids Essential fatty acids Sources of fat in the diet, including omega-3 and omega-6 fatty acids. Mentioned in: Nutritional Supplements , and numerous vitamins and minerals. And they also play a vital role in the Pacific Northwest ecosystem. When bears eat salmon, for example, they pass nutrients from salmon into the forest via scat (feces) and urine. Riparian riparian adj. referring to the banks of a river or stream. (See: riparian rights) (streamside stream·side n. The land adjacent to a stream. ) forest ecologist Jim Helfield at the University of Washington tested bear scat samples and tree cores to identify ocean and soil nutrients near Alaskan streams. Turns out, nutrients from salmon (including nitrogen from ocean sources) passed via bear poop Poop A slang term often used to describe people with insider information. Notes: Not the most illustrious name. See also: Insider Information fertilize trees near streams--in fact, trees near salmon streams grow up to three times faster than trees along streams without salmon! "Salmon and bears help ensure the health of streamside forests," says Helfield. Q: AREN'T MOST DAMS SALMON-FRIENDLY? When a salmon confronts a towering dam, the fish seeks a flow path around it. If no such path exists? The salmon may spend the rest of its days swimming haplessly at the dam's base. Most Columbia and Snake River dams feature fish ladders, a series of steps and pools that let adult salmon climb gradually up and over the dams (see diagram, "HOW SALMON SURVIVE DAMS"). But some salmon have trouble finding a fish-ladder entrance. Others reach the top only to reel back from the gush of dam water, then exhaust themselves climbing again. Mostly, fish ladders have proved successful in allowing adult salmon to migrate past dams, but don't provide a downstream path for migrating juveniles. Behind dams, lake fishes often thrive while river fishes like salmon suffer. Some lake fish prey on smolts that swim slowly in reservoirs--they're not drawn along quickly enough by a river current. Smolts also have to battle dam turbines, rotors or blades that generate electricity when turned by rushing hydroelectric dam water, which can shred young salmon. Other smolts spill over a dam's rim and get gas-bubble disease (similar to "the bends" that scuba divers get when they surface too quickly). When falling water becomes supersaturated su·per·sat·u·rate tr.v. su·per·sat·u·rat·ed, su·per·sat·u·rat·ing, su·per·sat·u·rates 1. To cause (a chemical solution) to be more highly concentrated than is normally possible under given conditions of temperature and with air, an excess of dissolved nitrogen gas is absorbed into a smolt's bloodstream, where it forms bubbles that block circulation and kill the fish. Q: SHOULD DAMS BE BUSTED? After four lower Snake River dams were completed in the '70s, the number of returning adult chinook salmon chinook salmon or king salmon Prized North Pacific food and sport fish (Oncorhynchus tshawytscha) of the salmon family. The average weight is about 22 lbs (10 kg), but individuals of 50–80 lbs (22–36 kg) are not unusual. plummeted from around 58,000 adults to around 23,000 between 1974 and 2000. "We need to take down the four lower Snake River dams," says media director Melissa Pease of Save Our Wild Salmon in Seattle. One proposed strategy to restore salmon populations: Breaching, or removing the dam's earthen earth·en adj. 1. Made of earth or clay: an earthen fortification; an earthen pot. 2. Earthly; worldly. portion--allowing a river to flow around the concrete structure. Supporters claim these dams provide less than 5 percent of the region's electric power, as well as no flood control or irrigation irrigation, in agriculture, artificial watering of the land. Although used chiefly in regions with annual rainfall of less than 20 in. (51 cm), it is also used in wetter areas to grow certain crops, e.g., rice. water. Breaching is also much cheaper than removing an entire dam. But opponents argue that breaching dams won't help save salmon, because their population decline is caused by other factors: unfavorable ocean conditions, spawning-habitat destruction, and overfishing Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans. More precise biological and bioeconomic terms define 'acceptable level'. . "Salmon runs in areas without dams have seen the same salmon declines," says Tom Flint, chairman of the Save Our Dams coalition. "Dams do have an impact on salmon, but it's very, very small." Opponents also maintain that dam-busting could severely impact the region's economy by eliminating a plentiful source of cheap electricity and of transporting crops downstream. Q: WHAT'S BEING DONE TO HELP SALMON? In the last three decades, the National Marine Fisheries Service The U.S. National Marine Fisheries Service (NMFS) is a United States federal agency. A division of the National Oceanic and Atmospheric Administration (NOAA) and the Department of Commerce, NMFS is responsible for the stewardship and management of the nation's living marine has implemented an unusual tactic to save salmon: driving smolts around dams! Workers load them on trucks or barges and motor them past Bonneville Dam, the last dam on the Columbia. While the free ride has improved smolt survival, migrating adult salmon numbers remained mysteriously low until the '90s. The reason? The stress of diversion, collection, and transportation may increase the smolts' susceptibility to disease and predation predation Form of food getting in which one animal, the predator, eats an animal of another species, the prey, immediately after killing it or, in some cases, while it is still alive. Most predators are generalists; they eat a variety of prey species. in the sea. Another possibility: Pacific Decadal Oscillation The Pacific Decadal Oscillation (PDO) is a pattern of Pacific climate variability that shifts phases on at least inter-decadal time scale, usually about 20 to 30 years. The PDO is detected as warm or cool surface waters in the Pacific Ocean, north of 20° N. , a 20-year-cycle in which the Pacific Ocean warms and cools. When the ocean is colder, salmon thrive; when it's warm they languish. The Pacific entered a cool phase in the late '90s, and in 2001 the number of returning chinook to the Snake River skyrocketed to more than 190,000 from a 1995 low of about 3,000. "Returning salmon runs are the largest they've been since 1938--when the first dam was built on the Columbia River," says Tom Flint. However, most returning salmon are produced in hatcheries or fish farms, and wild salmon still hover on extinction. For wild salmon to survive, they need human help fast. WHAT DO YOU THINK? Should dams be busted? Why or why not? Check out these Web sites to help form your opinion: nwd.usace.army.il/ps/colrvbsn.htm howdyneighbor.com/flyfisherman/mfarnell/ THE DALLES dalles pl.n. The rapids of a river that runs between the steep precipices of a gorge or narrow valley. [French, pl. of dalle, gutter, from Old French, from Old Norse dæla.] DAM features fish paths, but altered the Columbia River's natural downstream surge and salmon's migratory patterns. BEAR CHOW: Nutrients from salmon pass through bear poop to fertilize soil--part of the balance of the Pacific Northwest ecosystem. SILVERY SOCKEYE salmon sockeye salmon or red salmon Food fish (Oncorhynchus nerka) of the North Pacific that constitutes almost 20% of the commercial fishery of Pacific salmon. It weighs about 6 lbs (3 kg) and lacks distinct spots on the body. , one of six Pacific species, turn red before they spawn, or lay eggs. Only a few eggs of thousands escape predators to become adults. HOW SALMON SURVIVE DAMS An alternative to the current system would be the removal of earthen portions of dams, restoring the river's natural flow. Re-routing Nature's Flow Dams on the lower Snake and Columbia rivers interrupt the natural migrations of Pacific salmon and are considered a major factor in their declining numbers. Officials are debating alternatives to the present system for routing the fish around the dams. A. Downstream THE YOUNG GO TO SEA 1 SPILLWAYS Some juvenile fish bypass dams through spillways built into the dams. One concern: The large volume of water spilling through these gates can produce excessive amounts of gases harmful to fish. 2 TURBINES Others go through turbines, where high pressure and whirring whir v. whirred, whir·ring, whirs v.intr. To move so as to produce a vibrating or buzzing sound. v.tr. To cause to make a vibratory sound. n. 1. blades kill up to 10 percent of smolts. Some of those that make it through end up disoriented dis·o·ri·ent tr.v. dis·o·ri·ent·ed, dis·o·ri·ent·ing, dis·o·ri·ents To cause (a person, for example) to experience disorientation. Adj. 1. and vulnerable to predators. 3 BYPASS SYSTEM ... Large screens prevent fish from being drawn into the turbine intakes and direct them upward into a bypass channel. Some fish re-enter re·en·ter also re-en·ter v. re·en·tered, re·en·ter·ing, re·en·ters v.tr. 1. To enter or come in to again. 2. To record again on a list or ledger. v.intr. the river on the downstream side. ... AND TRANSPORT At some dams, fish are transferred to barges or trucks that transport them past the Bonneville Dam, the last dam interrupting their migration to sea waters. B Upstream THE ADULTS' RETURN TRIP Adult fish swimming upstream to spawn pass the dams through an artificial set of rapids and pools constructed of concrete. About 95 percent complete the journey, but how many live to reproduce is in dispute. A FISHY fish·y adj. fish·i·er, fish·i·est 1. Resembling or suggestive of fish, as in taste or odor. 2. Cold or expressionless: a fishy stare. 3. LIFE-CYCLE Natural Propagation ... Spawning females deposit eggs in gravel nests in streams, where the eggs are fertilized fer·til·ize v. fer·til·ized, fer·til·iz·ing, fer·til·iz·es v.tr. 1. To cause the fertilization of (an ovum, for example). 2. by adult males. Males and females then die. Some salmon species do not die after spawning ... Eggs hatch in streams and young fish live there until ready to migrate ... Hatchery hatchery a commercial establishment dedicated to the hatching of bird eggs to provide day old chicks and poults to the poultry industry. hatchery liquid the contents of unfertilized eggs. Used in petfood manufacture. Propagation ... Eggs from adult females are fertilized with sperm from multiple males to ensure genetic diversity. Eggs and young are cared for at the hatchery; smolts are released into streams ... As smolts travel from streams to main rivers and on to the ocean, some must pass dams and all must dodge predators ... Smolts enter the ocean ... Survivors grow to maturity at sea ... Ocean and river harvests reduce the numbers of returning salmon ... Adult fish enter the rivers and move upstream toward spawning areas ... On the way, they climb ladders at dams ... Changes in body color and form occur ... Did You Know? * Chinook are the largest and least abundant Pacific salmon species. * At maturity, chinook are generally 50 centimeters (20 inches) to 1 meter (39 in.) long and weigh around 7 to 14 kilograms (15 to 30 pounds). But some tip the scales at up to 27 kg (60 lbs). * The National Marine Fisheries Service has calculated the risk at 50 percent that all Snake River runs of spring and summer chinook will be extinct in 100 years. Cross-Curricular Connection Health: Research and compare the nutritional value of different types of fish, including salmon. [ILLUSTRATION OMITTED] National Science Education Standards The National Science Education Standards (NSES) are a set of guidelines for the science education in primary and secondary schools in the United States, as established by the National Research Council in 1996. Grades 5-8: structure and function in living systems * reproduction and heredity heredity, transmission from generation to generation through the process of reproduction in plants and animals of factors which cause the offspring to resemble their parents. That like begets like has been a maxim since ancient times. * regulation and behavior * populations and ecosystems * risks and benefit Grades 9-12: interdependence of organisms * behavior of organisms * natural resources * natural and human-induced hazards Resources For more information and activities, visit the University of Washington School of Fisheries' Salmon in the Classroom Web site: www.fish.washington.edu/sic/index.html Visit the following sites to learn about two opposing views. For saving salmon: www.columbia-snake.org For saving dams: www.saveourdams.com CHECK FOR UNDERSTANDING
Directions: Match the word in the left column with the correct phrase
in the right column.
1. spawn a. scent cells
2. turbines b. natural warming and cooling ocean
cycle
3. olfactory pits c. dam's hydroelectricity-producing
blades
4. olfactory receptors d. fish farm
5. hatcheries e. leave eggs behind to hatch
6. Pacific Decadal Oscillation f. juvenile salmon
7. smolt g. nostrils not connected to throat
8. alevin h. newly hatched salmon
ANSWER
1. e 2. c 3. g 4. a 5. d 6. b 7. f 8. h
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