Classical Hypothesis for Pacific SalmonEvolution and Diversification• Isolation during glacial advances• Problem: Fossil salmon pre-date Pleistoceneglaciations!Evolution of the Pacific Salmon• Pacific salmon evolved between 20million and 6 million years ago(Miocene).• Radiation of Pacific salmon intodistinct species coincides with upliftof Pacific Rim topography.The Skokomish River fossilsalmon locality is justupstream of the gorge of theSouth Fork at the edge of thePuget Lowland.Skokomish River, Sockeye Salmon4 year old, spawning populationMajor life history traitsestablished by 1 million years agoSalmon and Natural DisturbancesFor millions of yearssalmon thrived in alandscape shaped byfloods, volcaniceruptions, and naturaldisturbances.Archaeological excavations along the ColumbiaRiver confirm extensive salmon fishing for >9300years…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 salmonproduction in the Northeast Pacific ecosystem: Evidence of a nutrient deficit in the freshwater systems of thePacific Northwest. Fisheries, 25(1): 15-21.History, The 5th HStrikingly similarpattern of changes toriver systems andsalmon crises in GreatBritain, New England,and now the PacificNorthwest.HarvestThe earliest recorded salmon-fishinglegislation was an edict issued by King MalcolmII of Scotland in 1030 that established aclosed season for taking “old salmon”.HabitatA statute dating from the reign ofRichard the Lion-hearted declared thatrivers must be kept free of obstructionsso as to permit a well-fed three-year-oldpig, standing sideways in the stream, notto touch either side.Hydro (dams)An Act passed in the reign of King Robertthe First, in 1318, forbade the erectionof fixtures of any size or dimensions thatwould prevent the progress of salmon upand down a river.In 1714 George I enacted a law to prevent blockingsalmon from their spawning grounds in seventeenEnglish rivers.By 1868, all seventeen rivers protected by George Iwere either blocked or poisoned by pollution.[habitat and hydro]George I Tries to Save the SalmonAlexander Fraser proposed steps to increase thenumber of salmon in Scottish rivers (1833):(1) don’t block the ability of salmon to migrate upor down stream [hydro];(2) limit fishing intensity so as to not take the majority of the spawners [harvest];(3) prevent habitat degradation that could damagethe fishery [habitat].“If the Pigeons plagued us by theirabundance, the Salmon gave us even moretrouble. So large a quantity of thementers into this river that at night one isunable to sleep, so great is the noise theymake in falling upon the water afterhaving thrown or darted themselves in tothe air.”— N. Denys (1672 , p. 199).New World SalmonThe proliferation of small dams gradually blockedsalmon from New England’s rivers.First laws outlawing salmon-blocking dams datefrom 1709.Between 1820 and 1880 over one hundred andfifty fishery laws relating to salmon were passedby the state of Maine.Enforcement, provided for at the local level, wasvirtually nonexistant.Local control and lax enforcementGradual accumulation of manyindividual habitat impactsOver-reliance on hatcheries at theexpense of habitatLack of long-term planning andunderstanding of habitat-fishlinkages…Key factors in British and New England salmon declinesHave we learned any of these lessons?Are we really doing anything anydifferent in the Pacific Northwest?HarvestHydroHabitatThe supply and transport of water, sediment, andwood interact to structure salmon habitat.02000400060008000100001880 1900 1920 1940 1960Snags/YearRivers & 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 mostmajor 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 helpdescribe historical wetland habitat“Through marsh Covered with HardHack Willow and scattering firs.Standing water from 6 in to two feetdeep” --August 30, 1872“The water was 2 _ feet deep andappeared to be deeper fathernorthward, we therefore consider itunfit for cultivation and impracticableto now survey it” --November 2, 1866Descriptions of wetlands inSkagit 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 provideit quickly, before complications arise which maymake it impracticable, or at least very difficult.… If we procrastinate and put off our rescuingmission too long, it may be too late to do anygood. After the rivers are ruined and thesalmon gone they cannot be reclaimed … all thepower of the United States cannot restoresalmon to the rivers after the work ofdestruction has been completed.— Livingston Stone (1892)One of the few strategies that mightwork over the long run would be tocreate a network of SalmonSanctuaries by restoring forestedriver corridors along riverfloodplains.Urbanization changes the way that watermoves across and off the land, resulting inincreased high flows, and often turning thepre-urbanization 10 year flood into a post-urbanization annual flood.MostMoscrip and Montgomery, JAWRA, 1997Recurrence intervalDischarge(cfs)beforeafterPuget SoundPartnershiprecommendationsessentially ignorethe adverseimpacts likely tooccur due tofuturedevelopment.On October
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