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Salmon Species & Estuary Use  

Some salmon species use estuaries and nearshore areas longer than others.

 
More Use  
  • ocean type chinook
  • chum
  • ocean type coho
  • pink
  • Less Use  
  • stream type chinook
  • stream type coho
  • sockeye
  • Some salmon species pass through nearshore waters quickly on their way to sea. Others may spend months in estuaries, feeding, growing, and adjusting to salt water. A lot depends on the size of the salmon when it reaches the estuary. In general, larger salmon such as sockeye, coho and chinook yearlings are less dependent on estuaries and may pass through relatively rapidly. Smaller salmon such as chum, pink, and chinook fry and fingerlings may use estuaries and nearshore waters for up to 180 days.

     
    Pacific Salmon Species  
     

    Chinook Salmon
    Oncorhynchus tshawytscha  
     
    The "ocean-type" chinook generally spends a brief time in freshwater streams. It then migrates to estuary waters, where it may stay for an extended time before heading out to sea. The "stream-type" chinook lives one or more years in freshwater streams and typically passes through estuaries quickly before moving out to sea.
     
    Of all Pacific salmon species, "ocean-type" (fall) chinook rely most on estuaries and nearshore waters along Puget Sound - some stay as long as 189 days. Chinook fry and fingerlings move downstream to estuaries at a young age. Here they adapt to saltwater, hide from predators, and grow rapidly feeding on planktonic animals.  
     

    Saving Estuaries and Chinook

    • Puget Sound chinook salmon are a threatened species. Chinook populations in Puget Sound have declined 18 to 90 percent since the 1960's. One cause is the destruction of wetlands and estuaries.
    • Puget Sound has lost more than 70% of its tidal wetlands to filling, dredging, and diking - crucial areas for developing young chinook salmon.
     

    Chum Salmon
    Oncorhynchus keta  
     
    Chum fry travel downstream shortly after hatching, form dense schools, and spend a month or more in estuary waters. Young chum favor eelgrass meadows and often prey on small crustaceans such as harpacticoid copepods, gammarid amphipods, and isopods. Many genetically distinct runs exist on Puget Sound and Hood Canal. As many as three distinct populations may exist on the same river, passing through estuaries and on to sea at different rates.  
     

    Threatened Chum Salmon

    • Listed as a threatened species in 1999, the populations listed include all naturally-spawning summer-run chum salmon in Hood Canal and populations in Olympic Peninsula rivers between Hood Canal and Dungeness Bay.
    • Hood Canal summer-run chum have disappeared from several streams. Populations in other streams show severe decline.
     
    Sockeye salmon.
    Sockeye Salmon
    Oncorhynchus nerka  
     
    Sockeye spend one or two years developing in lakes. Large smolts typically pass quickly through estuary waters for ocean rearing grounds. One type of sockeye, however, migrates quickly down to estuaries and develops there over time.  
     

    Saving Sockeye Salmon

    • Because young sockeye rely on lakes or estuaries, areas where people also congregate, they are susceptible to water quality and habitat threats.
    • Sockeye salmon have greatly declined over the last 70 years and in some areas are now extinct.
     
    Pink Salmon.
    Pink Salmon
    Oncorhynchus gorbuscha  
     
    Pink salmon begin migrating downstream almost immediately after emerging from the gravel. Pinks move rapidly into tidal channels and nearshore nursery areas, often in schools and usually in darkness. Juvenile pinks grow quickly while in nearshore waters, up to 5-6% body weight per day. Preferred prey of young pinks includes small crustaceans (euphausids, amphipods, and cladocerans). After a few weeks to a few months in estuaries and nearshore regions, pink salmon move offshore, where they migrate at sea for 12-16 months.  
     

    Pink Salmon & Development

    • Schools of juvenile pink salmon have been observed in Puget Sound avoiding deeper waters near marinas and bulkheads ­ where they may be more vulnerable to predators.
     
    Coho salmon.
    Coho Salmon
    Oncorhynchus kisutch  
     
    When coho enter estuary waters, they may be two years old and relatively large. As larger smolts, coho may pass quickly through estuaries and out to sea. In some cases however, the transition to the ocean may be prolonged. Some coho never leave coastal waters and return early to spawn as immature "jacks." Another "ocean type" coho migrates as fry to brackish waters in estuaries. These juveniles may use tidal sloughs and flood plains for development.  
     
    Steelhead.
    Steelhead
    Oncorhynchus mykiss  
     
    Recently designated the same genus as Pacific salmon, steelhead are large rainbow trout that go to sea. Young steelhead spend two to three years in streams developing. In estuaries, larger smolts feed on insects, small crustaceans, and crab larvae. Studies show that steelhead from the Puget Sound area are genetically distinct from other regions. There may also be some genetic differentiation between populations from northern and southern Puget Sound. Even when Puget Sound steelhead migrate to the ocean, they may spend considerable time as juveniles or adults in the protected waters of the Sound.  
     
    Cutthroat Trout
    Cutthroat Trout
    Oncorhynchus clarki clarki  
     
    Recently designated the same genus as Pacific salmon, cutthroat can be found year round in shallow water close to shore. Juvenile cutthroat trout spend a range of times in estuaries. Some cutthroat trout may remain in nearshore/estuary waters most of their lives feeding on amphipods, isopods, shrimp, and young fish such as pink and chum salmon.  
     

    Salmon Species & Survival

    • Each stock of wild salmon is important. The genetic variation among salmon species and the range of estuary use helps salmon survive.
    • Of 148 stocks reviewed in Puget Sound in 1993, 11 stocks of Puget Sound Chinook, chum and steelhead were found to be in danger of extinction. 44 stocks including coho and Hood Canal pink salmon were "depressed" or below expected levels.

    Source: Salmon and Steelhead Stock Inventory, Washington Department of Fish and Wildlife, 1993. Fish images courtesy Washington Department of Fish and Wildlife.

    Related Topics

    Salmon, Why salmon use estuaries and nearshore waters.
    Salmon Life Cycle, The life cycle varies.
    Salmon & Nearshore, Plants provide food and shelter.
    Bulkheads, Bulkheads can damage salmon habitat.

    Related Links

    Puget Sound Nearshore Environments: Salmon Use, Large River Mouth, King County Department of Natural Resources. A color illustration showing zones used by juvenile salmon.

    Anadromous Fish Life History Profiles, Pacific States Marine Fisheries Commission. Anadromous fish species that inhabit the Pacific Northwest including salmon.

    Wild Salmon: Our Precious Natural Resource, Washington State Department of Fish & Wildlife. Salmon/Steelhead species information.

    Salmon & Steelhead, NOAA Fisheries Northwest Regional Office. Salmon information & programs, publications & resources, regulations & laws.

    Puget Sound Chinook Salmon ESU, NOAA Fisheries Northwest Regional Office. ESA listing status.   

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