Currently browsing: Predation

The thousands of double-crested cormorants nesting on the 5-mile-long Astoria-Megler Bridge in the Columbia River estuary that are damaging the bridge, causing safety problems and eating more salmon and steelhead smolts must go, according to a value engineering study led by the Oregon Department of Transportation.

A legislative bill sitting on Oregon Gov. Tina Kotek’s desk waiting for signature would give Oregon more flexibility in managing predatory non-native game fish species --such as bass and walleye -- that consume salmon and steelhead smolts in the Columbia River basin.

In 2022, anglers caught and removed more than 140,000 northern pikeminnow from the Columbia and Snake rivers, which the Bonneville Power Administration says is protecting hundreds of thousands of young salmon and steelhead from predation.

A program that has lethally removed sea lions from sections of the Columbia River and at Willamette Falls since 2008 is saving thousands of salmon and steelhead, many listed under the federal Endangered Species Act. The program is significantly dropping the risk of extinction for wild winter steelhead in the Willamette River, according to biologists.

A recent report on pinniped predation shows that the presence of California sea lions at Bonneville Dam has declined significantly since 2015 when 195 of the marine mammals were observed by the U.S. Army Corps of Engineers in the dam’s tailraces. The number in 2021 was just 24.

The same federal agency that previously had hazed and culled Caspian terns and double-crested cormorants at East Sand Island in the lower Columbia River estuary in order to reduce predation on salmon and steelhead smolts is now hazing cormorants nesting on the Astoria-Megler Bridge six miles upstream.

NOAA Fisheries and its Pinniped Task Force closed a chapter of its program to lethally remove California sea lions from Bonneville Dam. Determining that the removal of the sea lions saved nearly 56,000 adult salmon and steelhead, the Task Force called the 15-year effort a success.

Northwest states euthanized some 76 fish-eating California sea lions at Bonneville Dam over a five-year period through June 30, 2021, according to a recent report from the states to the National Marine Fisheries Service.

At the end of the first spring in which biologists have been allowed by federal permit to lethally remove both California and Steller sea lions in the Columbia and lower Willamette rivers, fisheries biologists have stopped the removal activity as sea lions have left Bonneville Dam and both rivers for coastal rockeries.

The Independent Scientific Advisory Board has released an analysis of two studies offering differing views on the effectiveness of avian predation control measures in the Columbia River basin. The scientists say further comparative research is needed to determine if hazing and killing terns and cormorants are boosting steelhead smolt-to-adult returns.

The Washington Department of Fish and Wildlife is taking public input on its state status review for Steller sea lions.

During the fall 2019 and spring 2020 monitoring seasons at Bonneville Dam, sea lions continued to prey on salmon, steelhead and sturgeon, but the proportion of California sea lions is continuing to drop while that of steller sea lions continues to rise, according to a draft annual pinniped report by the U.S. Army Corps of Engineers.

Pacific great blue herons could be scooping up as many as three percent of all juvenile salmon in the Salish Sea region and as many as six percent in some years with low water flow, according to a new University of British Columbia study.

The Bonneville Power Administration reports that in 2020, for the 23rd consecutive season, the Northern Pikeminnow Sport Reward Program met its annual goal to remove 10% to 20% of pikeminnow, 9 inches or longer, in the Columbia and Snake rivers that prey on juvenile salmon and steelhead. Due to Covid-19, however, catch numbers were far below average.

The U.S. Fish and Wildlife Service has issued the final rule and final environmental impact statement to “responsibly manage conflicts associated with double-crested cormorants” in the United States.

A new University of Washington and NOAA Fisheries study found that sea lions have the largest negative effect on early-arriving endangered chinook salmon in the lower Columbia River.

Confronted with trapping and euthanizing salmon-eating sea lions that are sometimes twice the size of California sea lions, states and tribes are upgrading equipment and procedures to begin capturing the larger Steller sea lions in the Bonneville Dam tailrace and at Willamette Falls, and eventually in Columbia River tributaries.

Scientists at the NOAA Northeast Fisheries Science Center have developed an unusually rich picture of who is eating whom off the Northeastern United States.

Sea lion removal at Bonneville Dam and Willamette Falls will restart in October, but with a twist that allows tribes and states to capture and euthanize far more sea lions, including both California and Steller sea lions, and to target sea lions in the lower Willamette River and from the I-205 bridge on the Columbia River upstream to McNary Dam, as well as the river’s tributaries.

Likely due to the Covid-19 pandemic, and recent smokey skies, the number of anglers this year participating in the Northern Pikeminnow Sport Reward Program is down 28 percent from this time last year. Currently, the 2020 harvest of northern pikeminnow on the Columbia and Snake rivers is on track to be the lowest on record.

The fish-eating sea birds on East Sand Island in the Columbia River estuary have been the target of management actions to reduce the number of double-crested cormorants and Caspian terns since the middle of the last decade.

Last month, the Columbia Basin Bulletin published an article about the recent U.S. Fish and Wildlife Service proposed rule and draft environmental impact statement related to management of double-crested cormorants.

Fisheries researchers estimated that over 2.5 million adult kokanee occupied Lake Pend Oreille in the fall of 2019. This is the highest count on record since the mid-1990’s. As summer heats up, reports are starting to roll in that anglers are reaping the benefits of a highly abundant kokanee population.

Sea lions bit out a big chunk of the spring salmon and steelhead run in 2019, taking 3.3 percent of the fish passing Bonneville Dam, January through May.

On May 12-14, NOAA Fisheries will convene a task force to make recommendations on the proposal to expand the lethal take of sea lions in the Columbia River basin. The sea lions have had a significant negative impact on salmon and steelhead listed under the Endangered Species Act, and they also consume species of concern -- lamprey and sturgeon.

A recent study found that active removal of predators in the San Joaquin-Sacramento Delta in California as a way to protect a native and imperiled species may not get the intended results.

In 2015, nearly half of steelhead smolts that began their journey to the ocean at Rock Island Dam on the upper Columbia River did not survive the onslaught of birds that feed on the smolts along the way, according to Blaine Parker, avian predation coordinator at the Columbia River Inter-Tribal Fish Commission.

Since 2015, when the efforts to suppress or eradicate non-native northern pike from Lake Roosevelt began, nearly 13,000 of the voracious fish have been removed from the huge reservoir that backs up behind Grand Coulee Dam on the upper Columbia River.

Northern pike were promoted to a short list of the most unwanted invasive species in the state of Washington on Friday by the state’s Fish and Wildlife Commission.

For the most part, the double-crested cormorants that abandoned one of the largest cormorant colonies in the world, located at East Sand Island in the lower Columbia River estuary, simply moved a couple of miles upstream to the Astoria-Megler Bridge, according to a study in process.

As efforts continue to curb the proliferation of northern pike in the Columbia River Basin, the state of Washington and co-management agencies are pursuing additional funding and flexibility to respond to the voracious predators entering the “anadromous zone” downstream from Grand Coulee Dam.

NOAA Fisheries has released a draft plan for public comment to remove and kill as many as 416 California and Steller sea lions each year in a 180 mile stretch of the Columbia River from just downstream of Bonneville Dam at river mile 112 upstream to McNary Dam at river mile 292.

With the growing worry about sea lion predation – both California and steller – on Endangered Species Act-listed salmon and steelhead in the Columbia River basin, three states and four Native American Tribes applied last week to NOAA Fisheries to lethally remove as many as 286 California and 130 steller sea lions from the river and some tributaries.

A highly anticipated economics report on the impacts of northern pike in the Columbia River Basin will get a rollout next week before the Northwest Power and Conservation Council in Portland.

The Oregon Department of Fish and Wildlife was permitted by NOAA Fisheries in November 2018 to remove and euthanize up to 93 California sea lions at Willamette Falls to protect wild runs of spring chinook and winter steelhead transiting the Falls. Both species are listed as threatened under the federal Endangered Species Act.

The number of sea lions observed at Bonneville Dam in March was below the 10-year average and spring chinook salmon and steelhead, the fish sea lions like to feast on during the spring at the dam, were also far below average