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Ecology and salmon related articles

Independent Science Board: 'Density Dependence,'
Diminished Habitat Constraining Salmon Recovery

by Staff
Columbia Basin Bulletin, February 27, 2015

(Jamie Francis) Cormorants, like these, and terns are eating nearly 20 million baby salmon a year on East Sand Island, a tiny man-made Oregon island.
Fishery managers and researchers engaged in salmon and steelhead recovery efforts need to better understand, and address, issues related to what has become a smaller and less hospitable Columbia River basin world, according to a Feb.25 report issued by the region's Independent Scientific Advisory Board.

The new report says that "Many salmon populations throughout the interior of the Columbia River basin are experiencing reduced productivity associated with recent increases in natural spawning abundance, even though current abundance remains far below historical levels.

"Density dependence is now evident in most of the ESA-listed populations examined and appears strong enough to constrain their recovery."

A total of 13 salmon and steelhead stocks are listed for protections under the Endangered Species Act.

Why is this happening? the ISAB asks. And answers.

The report, "Density Dependence and Its Implications for Fish Management and Restoration in the Columbia River Basin" can be found at:

"In response to a March 2014 assignment from the Northwest Power and Conservation Council, NOAA Fisheries, and Columbia River Indian tribes, the Independent Scientific Advisory Board (ISAB) reviewed the implications of density dependence in fish populations in the Columbia River Basin," according to the document's executive summary.

The 11-member ISAB was established in 1996 by the NPPC and NOAA Fisheries to provide on request independent scientific advice and recommendations regarding scientific issues posed by the respective agencies on matters that relate to their fish and wildlife programs. Columbia River Basin tribes were added as equal and permanent partners in the sponsorship of the ISAB.

The ISAB's key recommendations listed in the report's executive summary include:

Related Pages
The Density Dilemma: Limitations on Juvenile Production in Threatened Salmon Populations by Walters, Copeland, Venditti, Ecology of Freshwater Fish, 2/25/13

Independent Science Board: 'Density Dependence,' Diminished Habitat Constraining Salmon Recovery
Columbia Basin Bulletin, February 27, 2015

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