Sunday, May 03, 2009

Global Warming Cooking Salmon to Extinction?

Pacific Northwest salmon stocks are severely endangered by global warming.

Salmon eggs need a steady supply of cold, freshwater in their spawning streams to hatch. If the water flow is interrupted - dead eggs. If the water supply gets too warm - dead eggs. It's why we look anxiously this time of year to the snowpack on our mountain tops. That's what ensures an adequate flow of sufficiently cold water to see hatchlings safely out to sea.

Global warming could spell the end to our salmon stocks. While the region is expected to remain wet in the winter months, snowpacks may decline. And what water does reach the spawning streams may be heated beyond the tolerable limits of salmon eggs. From McClatchey Newspapers:

Climate change already has made rivers warmer and spring runoff earlier, disrupting the life cycle of the fish that are an icon of the region.

No matter what actions the world takes to reduce greenhouse gases, river temperatures in more than half of the lower-elevation watersheds may exceed 70 degrees by 2040 - too hot for salmon.

"The only salmon that are going to survive the century mark are the ones in the large populations in the higher elevations that are still going to have snow and cold water," said Jim Martin, a former chief of fisheries for the state of Oregon.

But even these runs and those as far north as Alaska would be threatened if the world does not reduce gases like carbon dioxide over the next 50 years.

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