Classical 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 Salmon 4 year old spawning population Major life history traits established by 1 million years Salmon and Natural Disturbances For 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 2004 Status of Salmon Populations Today Region Alaska British Columbia Puget Sound Washington Columbia Basin Oregon California Percent of Historical Run Size 106 36 8 2 2 7 5 California Oregon Washington Idaho 5 Gresh 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 H Strikingly similar pattern of changes to river systems and salmon crises in Great Britain New England and now the Pacific Northwest Harvest The 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 Habitat A 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 George I Tries to Save the Salmon 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 Alexander Fraser proposed steps to increase the number of salmon in Scottish rivers 1833 1 up don t block the ability of salmon to migrate 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 New World Salmon 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 The 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 ey factors in British and New England salmon declines Local control and lax enforcement Gradual accumulation of many individual habitat impacts Over reliance on hatcheries at the expense of habitat Lack of long term planning and understanding of habitat fish linkages Have we learned any of these lessons Are we really doing anything any different in the Pacific Northwest Harvest Hydro Habitat The supply and transport of water sediment and wood interact to structure salmon habitat Army Corps of Engineers aggressively de snagged American Rivers 10000 Rivers Harbors Skagit River All Rivers 8000 6000 4000 2000 0 Collins et al 2002 1880 1900 1920 1940 1960 Nisqually River Floodplain Numerous floodplain channels with inlets controlled by log jams Collins et al 2001 Big Trees Influenced Big Rivers Stillaguamish River Washington Single floodplain channel with evidence of remnant side channels Collins et al 2001 Historical changes in1860 salmon habitat along the Skagit River Skagit Huge 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 Estimating historical aquatic habitat in wetlands Historical wetland habitats Skagit River estuary Seasonal water depths from GLO field notes help describe historical wetland habitat Descriptions of wetlands in Skagit Flats The water was 2 feet deep and appeared to be deeper father northward we therefore consider it unfit for cultivation and impracticable to now survey it November 2 1866 Through marsh Covered with Hard Hack Willow and scattering firs Standing water from 6 in to two feet deep August 30 1872 Area hectares Skagit 8 000 NO 4 000 W W S 0 CHANNEL TIDAL SEASONAL Seasonal inundation 1 ft for most of season W winter W S winter summer Change to wetland area in four North Sound estuaries deltas Wetland area hectares mid 1800s 20 000 mid 1900s 20 000 P RT 10 000 10 000 ESS EEM 0 0 NKS SKG STL SNH NKS SKG STL EEM estuarine emergent ESS estuarine scrub shrub RT riverine tidal P palustrine SNH Provide 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 salmon to the rivers after the work of destruction has been completed Livingston Stone 1892 One of the few strategies that might work over the long run would be to create a network of Salmon Sanctuaries by restoring forested river corridors along river floodplains Urbanization changes the way that water moves across and off the land resulting in increased high flows and often turning the pre urbanization 10 year flood into a post urbanization annual flood Most after Discharge cfs before Recurrence interval Moscrip and Montgomery JAWRA 1997 Puget Sound Partnership recommendation s essentially ignore the adverse impacts likely to occur due to future development On October 26 2006 fourteen so called experts sent a letter to the Puget Sound Partnership expressing
View Full Document
Unlocking...