Life Cycle of the Pacific Salmon – YouTube Dictation Transcript & Vocabulary

1.[Music] every year pacific salmon migrate from their home stream to the sea and back again this incredible journey can be hundreds or even thousands of miles long during their migration salmon play an important role in the health and stability of ecosystems making them a keystone species their long journey starts here in a riverbed where thousands of tiny eggs have been laid in a gravel nest called a red the eggs remain in the gravel throughout the winter while the embryos develop in late winter or early spring eggs hatch and the alvins emerge these tiny fish live off the nutritious yolk sacks that hang off their stomachs during this stage they stay under the cover of their gravel nests despite this relative safety many things can still harm salmon in their early stages of life rising water temperatures and predators such as blue herons osprey and kingfishers they will not leave the protection of the gravel until the yolk is used up in about 12 weeks at that time the young salmon called fry swim up to the surface gulp air to fill their swim bladders and begin to feed too weak to travel upstream the little fry begin to drip downstream along the way they stop at calmer pools to rest and feed on zooplankton and small bugs some species immediately head out to sea while others spend up to two years in fresh water migrating to sea is a long and arduous journey the young salmon will spend this time avoiding predators and imprinting the smells of their home stream into their memory eventually they make their way towards an estuary estuaries are where fresh water and salt water meet this brackish water provides many nutrient-rich foods for growing salmon here young salmon undergo many changes to transition from living in fresh water to salt water this process is known as smultification during smultification salmon develop a dark back a light belly and will change to have silvery colors this coloring will help them hide in the open ocean smolts seek deeper water and avoid light and their gills and kidneys begin to change so they can process salt water young fish remain in the estuaries in tidal creeks feeding on small fish insects crustaceans and mollusks meanwhile older fish gradually move into deeper saltier water until they enter the ocean some salmon remain in coastal waters others travel thousands of miles through the open ocean depending on the species they will stay at sea for one to seven years as they travel they will feed on animals such as fish squid eels and shrimp these ocean adults have grown larger and stronger in order to prepare for their difficult journey home this journey begins when they are ready to spawn and they are guided back by the smells of their home stream on their way back to the estuary they will have to navigate past fissures and predators such as porpoises sharks and seals those that do make it back to the estuary will face many obstacles in their battle upstream such as waterfalls dams and even more predators when migrating adults reach fresh water they stop eating during the remainder of their journey their bodies prepare to reproduce they change color from a silver to a brown green or red depending on the species the males of some species develop a hook snout humpback and elongated teeth this transformation occurs to attract potential mates and to defend spawning territory upon reaching their natal stream females build nests they turn on their side and use their tails to dislodge stones or pebbles males fight with other males for spawning rights with a female the dominant male will court a female and she will lay her eggs in the nest while the male will fertilize them with milk the female then covers the nest with loose gravel and moves upstream to prepare another red after swimming hundreds or even thousands of miles to get here and having completed their quest the salmon's energy is completely drained most die within a few days of spawning while the journey of these salmon has come to a close the nutrients from their decomposing bodies will fertilize the stream and provide food for insects and microorganisms nourishing the next generation of salmon bears wolves otters birds and other animals bring nutrient-rich droppings as well as uneaten parts of salmon into the forest helping to fertilize the surrounding land pacific salmon have been nourishing our culture's economies and ecosystems for millions of years the choices we make today affect salmon and all the species that depend on them visit www.fisheries.noaa.gov to learn how you can be a salmon steward and ensure the cycle continues [Music] you