Monday, September 21, 2009

Dead Salmon: Lifeblood of Rivers

Salmon leaping up waterfalls and surging into small streams: These are the images we're used to seeing of fish migrations.

Salmon are brightly, photgenically red in their final days--and then quickly become less so.

The above photo--taken this weekend near Stanley--captures the real end of the journey for spawning salmon. But it's not the end of the salmon's impact on streams.

Dead, decaying salmon are vitally important for our waterways, forests and meadows.

Where viable runs of salmon occur, they return vital nutrients to waterways, feeding aquatic insects and fish. Studies have found that streamside vegetation in salmon spawning areas is dependent on nutrients from dead fish.

Black and grizzly bears, otters, mink, bald eagles, ospreys and other predatory mammals and birds feed directly on the salmon carcasses. Bears drag thousands of carcasses away from the river, fertilizing trees, shrubs and grasses.

Rainbow trout and other fish often follow dying salmon and feed on pieces that fall off the salmon as they decompose--unsavory to us, perhaps, but a protein feast for trout.

In short, the whole river depends on a healthy, large run of salmon. As is evidenced in watersheds like Bristol Bay, a large salmon run can feed humans, wildlife and the river--and we should be working to ensure that such watersheds remain protected.

In Idaho, for many rivers we can only guess. But by continuing to work on salmon restoration, perhaps one day we can see rivers in their full glory--rivers brought to life by dying salmon.--Matt Miller

Photo by Michael Gordon.

1 comment:

Robert Mortensen said...

Ah! The great circle of life!