Tuesday, January 5, 2010

An Extinction Time Bomb. Climate Change and Threatened Salmon

The UN has declared 2010 the "Year of Biodivesity." Biodiversity is disappearing at an alarming rate across the globe and and IUCN (International Union for the Conservation of Nature) identified salmon as a group of species particularly likely to become extinct due the effects of climate change.

While this is somewhat of a generalization since each species of salmon will likely respond to climate change differently, it highlights the challenges salmon face over the coming century. Rising sea surface temperatures, changing wind and weather patterns and changes in coastal upwelling mean that salmon in the southern end of their range may experience far more hostile conditions in the Ocean than they have in their recent evolutionary history. Already many populations of salmonids are depressed in the southern range meaning these sub-populations have a high extinction risk.

Story on the UN's efforts and the 10 species facing the highest extinction risk:

All this means that there is no time to waste recovering salmon populations in the southern part of the range. The Snake River stands out as a perfect illustration of this challenge. The Obama administration recently chose not to push for removal of the Lower Snake River dams, opting instead to postpone consideration of breaching until salmon populations have declined further. During the 1990s ocean and in-river conditions on the Columbia were poor for juvenile salmon and steelhead survival and populations throughout the basin crashed to all time lows. Sockeye returns to Redfish Lake numbered in the Single digits in some years. Follwing an apparent change in ocean conditions at the end of the last decade, marine survival and consequently numbers of fish in the Columbia have improved substantially.

We're constantly barraged with the illusion of abundance by the banner returns of hatchery salmon to the system however the reality is the Columbia is on the path towards extinction. Wild returns are shadows of historic abundance and without swift action, populations will continue to decline when conditions turn more hostile in the ocean. Simply mitigating for extinction with hatchery production and habitat restoration will not save the wonderful, unqiuely adapted steelhead, chinook and sockeye of the Snake and Upper Columbia. Nor will it bring back the abundant wild Coho once found in the systems.

Big Returns of Hatchery Coho to the Upper Columbia:

The tragedy is that dam removal on the Snake would bring the fish back. The current mortality imposed on outmigrating salmon at each hydroproject is in the ballpark of 5-10% meaning populations would benefit greatly from the removal of the 4, outdated dams on the Lower Snake. Sadly long standing salmon defender Federal Judge James Redden of Oregon appears ready to accept the updated version of the 2008 BiOp. We can only hope that sooner rather than later those dams will come out, otherwise it may be too late.


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