A large die-off of an unglamorous fish have attracted rare visitors to a Snake River dam pool.
The demise of hundreds of American shad, described by wildlife officials “as the piscatorial Rodney Dangerfield” for the respect they don’t get, attracted huge numbers of birds to the Lower Snake River to dine on the dead and dying fish. Among them were gulls rarely, or never, seen in this area before.
Mike Denny, an avid birder and past president of the Blue Mountain Audubon Society, said he’s never seen anything like the numbers of dead fish as well as the flocks flying in to feast on them.
On a field trip to Lower Monumental Dam a few weeks ago, Denny said he and others observed flocks of gulls numbering in the thousands made up of least 10 different species. That number of different gull species “is unheard of in the interior of the Pacific Northwest,” he said.
Among the visitors was a slaty-backed gull, a bird native to Asia and not expected to be seen anywhere east of the Cascades. It’s appearance was the first recorded sighting of the bird in Eastern Washington, Denny said.
Two other “super rare” visitors were a group of lesser black-backed gulls, a Eurasian species, and a glaucous gull. The glaucous is normally found in the Arctic and is the largest gull in the world with a wingspan that can reach up to 64 inches, Denny said.
Other bird species snapping up the bounty of shad were flocks of great egrets, “the largest winter concentration we’ve ever seen on the Snake River,” Denny said.
There were also “loads” of mallards, common goldeneye ducks, great blue herons and double-crested cormorants.
Denny said fishermen he’s talked with began noticing the shad die-off in late November. He said he saw what appeared to be “thousands” of the fish in the area between Lower Monumental Dam and Ice Harbor Dam.
Jeremy Trump, a fish biologist with the Washington Department of Fish and Wildlife, confirmed there has been a die-off of shad and said it consisted mostly of juvenile fish. He said the exact cause has not been determined, however, it could have been weather and temperature related.
Denny also speculated the hot summer played a role, causing more of the juvenile shad to swim upriver seeking cooler water. As the seasons changed, the larger than normal population then exhausted its food supply, leading many to die of starvation.
That there was a larger number of shad in the river in 2015 is reflected in the fish counts recorded by the U.S. Army Corps of Engineers at Ice Harbor and Lower Granite dams.
At Ice Harbor Dam, watchers counted about 220,757 shad passing through the fish ladder during 2015 before the run ended in August. About 38 percent of that number, 84,833, made it up the Snake River, where they were recorded at Lower Granite Dam in Garfield County.
The 2015 numbers were far above totals recorded in previous years. In 2014, about 90,790 shad were counted at Ice Harbor, of which only 1,206 made it to Lower Granite, according to Corps records. The year before the numbers were 193,525 at Ice Harbor and 1,892 at Lower Granite.