Caspian tern predation on steelhead smolts in the Columbia River has reduced the size of the juvenile migration by more than 20 percent each year also has reduced the number of adult steelhead that return to the river several years later.
The federal agency responsible for protecting sea birds under the Migratory Bird Treaty Act is instead proposing to “responsibly manage” double-crested cormorants across the nation by permitting lethal taking of birds that eat fish, such as salmon and steelhead smolts, by states and tribes.
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.
Idaho Fish and Game has contracted with a company to net lake trout in Stanley Lake during two-weeks in early June to reduce their population and reduce risk to endangered sockeye salmon populations. After the netting, sterile lake trout will be restocked in the summer and fall to continue to provide anglers a lake trout fishery at Stanley Lake.
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.