Salmon are one of the most incredible aquatic animals in the kingdom with a life cycle that sounds like a Greek tragedy. Unfortunately, humans have been amplifying that tragedy for over a century, threatening the fish’s existence with water pollution, habitat destruction, and now climate change.
To increase the number of returning salmon, we have dotted the Columbia River basin with hatcheries. It’s the “we can just keep making more” syndrome. But if the environment is no longer suitable for salmon, they won’t do well.
To protect salmon, the legal water temperature limit for the Columbia River is 68 degrees. But Columbia Riverkeeper volunteers have found 70-degree water in much of the mainstem and the Oregon Department of Environmental Quality said temperatures have exceeded Clean Water Act limits for a number of years.
Salmon can’t live in water of that temperature for very long. That means cold water refuges become critically important. But as it gets warmer, the Columbia gets less hospitable to salmon.
So here’s the thing: high summer dam reservoir temperatures are now routine and temperatures on the mainstem of the river are controlled by the dams. Therefore, temperature violations will be hard to address. Bass fishing, anyone?
