Slide 1Slide 2Classical Hypothesis for Pacific Salmon Evolution and DiversificationEvolution of the Pacific SalmonSlide 5Slide 6Slide 7Salmon and Natural DisturbancesSlide 9Status of Salmon Populations TodaySlide 11Slide 12HarvestHabitatHydro (dams)Slide 16Slide 17Slide 18Slide 19Slide 20Slide 21Slide 22Slide 23Slide 24Slide 25Slide 26Slide 27Army Corps of Engineers aggressively “de-snagged” American RiversSlide 29Slide 30Slide 31Slide 32Slide 33Slide 34Slide 35Slide 36Slide 37Slide 38Slide 39Slide 40Slide 41Slide 42Slide 43Slide 44Slide 45Slide 46Slide 47Slide 48Slide 49Slide 50Classical Hypothesis for Pacific Salmon Evolution and Diversification•Isolation during glacial advances•Problem: Fossil salmon pre-date Pleistocene glaciations!Evolution of the Pacific Salmon•Pacific salmon evolved between 20 million and 6 million years ago (Miocene).•Radiation of Pacific salmon into distinct species coincides with uplift of Pacific Rim topography.The Skokomish River fossil salmon locality is just upstream of the gorge of the South Fork at the edge of the Puget Lowland.Skokomish River, Sockeye Salmon4 year old, spawning populationMajor life history traits established by 1 million years agoSalmon and Natural DisturbancesFor millions of years salmon thrived in a landscape shaped by floods, volcanic eruptions, and natural disturbances.Archaeological excavations along the Columbia River confirm extensive salmon fishing for >9300 years…Butler and O’Connor, Quaternary Research, v. 62, p 1-8, 2004Status of Salmon Populations TodayRegion Percent of Historical Run Size •Alaska 106•British Columbia 36 •Puget Sound 8•Washington <2•Columbia Basin <2•Oregon 7•California 5•California, Oregon, Washington, Idaho 5Gresh, T., J. Lichatowich and P. Schoonmaker (2000) An estimation of historic and current levels of salmon production in the Northeast Pacific ecosystem: Evidence of a nutrient deficit in the freshwater systems of the Pacific Northwest. Fisheries, 25(1): 15-21.History, The 5th HStrikingly similar pattern of changes to river systems and salmon crises in Great Britain, New England, and now the Pacific Northwest.HarvestThe earliest recorded salmon-fishing legislation was an edict issued by King Malcolm II of Scotland in 1030 that established a closed season for taking “old salmon”.HabitatA statute dating from the reign of Richard the Lion-hearted declared that rivers must be kept free of obstructions so as to permit a well-fed three-year-old pig, standing sideways in the stream, not to touch either side.Hydro (dams)An Act passed in the reign of King Robert the First, in 1318, forbade the erection of fixtures of any size or dimensions that would prevent the progress of salmon up and down a river.In 1714 George I enacted a law to prevent blocking salmon from their spawning grounds in seventeen English rivers. By 1868, all seventeen rivers protected by George I were either blocked or poisoned by pollution. [habitat and hydro] George I Tries to Save the SalmonAlexander Fraser proposed steps to increase the number of salmon in Scottish rivers (1833):(1) don’t block the ability of salmon to migrate up or down stream [hydro];(2) limit fishing intensity so as to not take the majority of the spawners [harvest];(3) prevent habitat degradation that could damage the fishery [habitat].“If the Pigeons plagued us by their abundance, the Salmon gave us even more trouble. So large a quantity of them enters into this river that at night one is unable to sleep, so great is the noise they make in falling upon the water after having thrown or darted themselves in to the air.” — N. Denys (1672 , p. 199).New World SalmonThe proliferation of small dams gradually blocked salmon from New England’s rivers.First laws outlawing salmon-blocking dams date from 1709.Between 1820 and 1880 over one hundred and fifty fishery laws relating to salmon were passed by the state of Maine. Enforcement, provided for at the local level, was virtually nonexistant.Local control and lax enforcementGradual accumulation of many individual habitat impactsOver-reliance on hatcheries at the expense of habitatLack of long-term planning and understanding of habitat-fish linkages…Key factors in British and New England salmon declinesHave we learned any of these lessons?Are we really doing anything any different in the Pacific Northwest?HarvestHydroHabitatThe supply and transport of water, sediment, and wood interact to structure salmon habitat.02000400060008000100001880 1900 1920 1940 1960Rivers & HarborsSkagit RiverAll RiversArmy Corps of Engineers aggressively “de-snagged” American RiversCollins et al. (2002)Nisqually River FloodplainNumerous floodplain channels withinlets controlled by log jams Collins et al. (2001)Big Trees Influenced Big RiversStillaguamish River, WashingtonSingle floodplain channel withevidence of remnant sidechannels Collins et al. (2001)Skagit 1860Historical changes in salmon habitat along the Skagit RiverHuge losses of side channels and valley bottom wetlands along most major Puget Sound rivers, yet the story for each river is unique.Collins et al. (2001)Seasonal inundation (> 1 ft for most of season):W: winter W&S: winter & summer04,0008,000CHANNEL TIDAL SEASONALSkagitW&SWNOArea (hectares)Seasonal water depths from GLO field notes help describe historical wetland habitat“Through marsh Covered with Hard Hack Willow and scattering firs. Standing water from 6 in to two feet deep” --August 30, 1872“The water was 2 ½ feet deep and appeared to be deeper father northward, we therefore consider it unfit for cultivation and impracticable to now survey it” --November 2, 1866Descriptions of wetlands in Skagit Flats:Estimating historical aquatic habitat in wetlands:Historical wetland habitats, Skagit River estuarymid 1800s mid 1900s010,00020,000NKS SKG STL SNHPRTESSEEM010,00020,000NKS SKG STL SNHWetland area (hectares)EEM=estuarine emergent; ESS=estuarine scrub-shrub; RT=riverine-tidal; P=palustrineChange to wetland area in four North Sound estuaries/deltasProvide some refuge for the salmon, and provide it quickly, before complications arise which may make it impracticable, or at least very difficult. … If we procrastinate and put off our rescuing mission too long, it may be too late to do any good. After the rivers are ruined and the salmon gone they cannot be reclaimed … all the power of the United States cannot restore
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