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Ecology and salmon related articles

Estuary Cormorant Colony Consuming 18 Percent
of Juvenile Salmonids; Corps Scoping Alternatives

by Staff
Columbia Basin Bulletin, Novemeber 2, 2012

Last year, cormorants were estimated to have consumed more than 22 million salmon and steelhead smolts. The U.S. Army Corps of Engineers has kicked off a public scoping process to determine how to best manage a large salmon-munching colony of double-crested cormorants nesting on East Sand Island in the Columbia River estuary.

Meetings will be held this month in Portland and Astoria, Ore., and in Olympia, Wash., to gather public input.

The double-crested cormorant colony on East Sand Island has grown from 100 nesting pairs in 1980 to an estimated 13,000 nesting pairs in 2011, the largest single colony in western North America.

The sheer numbers of big birds nesting at the island has resulting in a plundering of juvenile salmon and steelhead that attempt to swim past on their way to the Pacific Ocean to grow and mature. Those fish include wild stocks from the upper, mid and lower Columbia, the Willamette and the Snake rivers that are listed under the Endangered Species Act.

Last year double crested cormorants consumed more than 20.5 million salmonids, according to researchers' preliminary estimates. The cormorants' toll on young salmon and steelhead last year was the largest on record for research dating back to the 1990s.

From 2000 through 2009, the colony consumed an average of 8.2 million hatchery and ESA-listed juvenile salmonids per year, but the consumption increased to an estimated 19.2 million in 2010 and then 20.5 million last year (approximately 18 percent of the entire Columbia River out-migrating salmon for those years), according to the Corps.

Caspian terns -- about 7,000 nesting pairs -- that shared the island with the cormorants consumed about 4.8 million juvenile salmonids in 2011.

The terns have a bit of a longer history on East Sand. The steady growth of the tern colony at Rice Island, a resulting increase in predation on salmon, forced an action plan in 1999 that diverted the terns to East Sand, which is located 16 miles downstream near the river mouth. The theory was that by discouraging nesting at Rice and encouraging nesting nearer the Pacific Ocean at East Sand, the terns would have more marine fish available to eat and would consume fewer salmon.

It worked; annual salmon consumption by Caspian terns was more than halved at East Sand as compared to Rice.

An environmental impact statement and management plan was developed for terns in order to further reduce predation. Since 2009, the Corps has reduced the size of the East Sand Island nesting site by two-thirds in hopes terns would move elsewhere. Terns like wide-open sandy nesting sites. The East Sand tern nesting area was vegetated in order to dissuade tern use.

The agency has constructed islands as replacement habitat at Malheur Lake Fern Ridge, Summer and Crump lakes in Oregon and Orems Unit and Sheepy and Tule lakes in California. The islands are designed to mimic the type of habitat the terns prefer. Additional California sites are planned.

The blossoming double-crested cormorant colony at East Sand poses a different set of problems because of differing behaviors. The just-launched scoping process is aimed to gathering ideas about how the cormorant colony might be managed.

"It's wide open right now," said the Corps' Diana Fredlund. During the 1997-2010 period the cormorant colony on East Sand Island increased by 170 percent and is now believed to be the largest known breeding colony for the species in western North America (40 percent of the total western population).

The Corps has scheduled a number of public meetings as it prepares to draft an environmental impact statement to manage the big birds. The cormorants are protected under the Migratory Bird Treaty Act.

According to the Corps, the cormorant population increase has led to concerns over their potential impact on the recovery of the 13 threatened or endangered Columbia River basin salmonids that swim past the island.

An interagency working group was formed in 2010 to address the role of double-crested cormorant predation in the estuary on the recovery of ESA-listed salmon. No decisions have been made regarding how to manage the colony.

The group identified preliminary management alternatives, which included reducing the colony size on East Sand Island. Those preliminary management alternatives included reducing the colony size on East Sand Island through various methods by 25 percent, by 50 percent and by 75 percent.

But the full range of management alternatives to address the predation will be developed through the scoping process.

Methods to reduce the colony's size could involve a combination of actions to dissuade cormorants from nesting on the island. These actions may include modifying available habitat; conducting hazing activities during the nesting season to prevent colony establishment; selecting a lethal component (collection of eggs, nests and/or possible take of adults); and monitoring cormorants as they leave the island to determine the potential impacts of their dispersal.

The Corps, as the lead agency for the EIS, is working with its cooperating agencies: U.S. Fish and Wildlife Service, U.S. Department of Agriculture Animal Plant Health Inspection Service and Wildlife Services and Washington Department of Fish and Wildlife. Representatives from the Corps and the cooperating agencies will be on hand to discuss concerns or comments in an open house format. The meetings will be facilitated to encourage information sharing.

Nov. 8, 5 to 8 p.m.
Phoenix Inn
415 Capitol Way N
Olympia, WA 98501

Nov. 13, 5 to 8 p.m.
Red Lion Lloyd Center
1021 NE Grand Ave.
Portland, OR 97232

Nov. 15, 5 to 8 p.m.
Holiday Inn Express
204 West Marine Drive
Astoria, OR 97103

Members of the public are encouraged to visit the Corps' website for the EIS at , to learn more about the issues and research concerning double-crested cormorants in the estuary, to find a schedule for the draft EIS and to sign up for a mailing list to receive updates during the EIS process.

The public is strongly encouraged to review the materials on the website, contact the Corps for additional information and attend one of three public meetings in November.

Comments may be made in writing, electronically, by mail or over the phone. Comments will be categorized and summarized in a scoping report and used to inform the Corps' decision-making process. This is not the only opportunity for the public to provide input. There will be additional opportunities to comment during the EIS process.

Mailed comments must be postmarked by Dec. 21 and sent to:

Sondra Ruckwardt, project manager
Attn: CENWP-PM-E-12-06
U.S. Army Corps of Engineers, Portland District
P.O. Box 2946 Portland, Oregon 97208
Phone: 503-808-4691

The Corps of Engineers is the federal land manager of East Sand Island and the lead agency under the National Environmental Policy Act for the EIS. A Notice of Intent was published in the Federal Register on July 19, 2012, that announced the Corps' proposal to prepare a DEIS.

In its 2008 Biological Opinion and 2010 Supplemental Biological Opinion on the Federal Columbia River Power System's impacts on listed salmon, NOAA Fisheries directed the federal action agencies administering the FCRPS to analyze impacts of estuary cormorants on survival of Columbia River juvenile salmonids and develop a management plan to reduce cormorant predation, if warranted.

The BiOp "reasonable and prudent alternative" is intended to mitigate for dam impacts on the fish. NOAA Fisheries is charged with assuring listed salmon and steelhead stocks are not jeopardized. The Corps and Bureau of Reclamation, which operate the FCRPS dams on the mainstem Columbia and Snake, and the Bonneville Power Administration, which markets power generated at the hydro projects, are the action agencies obliged to implement the BiOp RPAs.

Estuary Cormorant Colony Consuming 18 Percent of Juvenile Salmonids; Corps Scoping Alternatives
Columbia Basin Bulletin, Novemeber 2, 2012

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