Whether you sponsored a smolt in Survive the Sound or not, you’ve probably heard that Washington’s inland saltwaters appear to be deadly for outmigrating steelhead, and a new paper further strengthens that case.
Fishery researchers looking at stocks across the region found an unusual signal for Puget Sound stocks relative to those on the Washington and Oregon Coasts, Lower Columbia and Strait of Juan de Fuca.
“Our paper shows that marine survival of Puget Sound steelhead is different — and lower — than steelhead not from the Sound. Also, the work suggest that it’s early marine survival — right after the young steelhead hit salt water — that seems to be driving the marine survival patterns,” says Neala Kendall, who works for the Washington Department of Fish and Wildlife.
Kendall’s and two colleagues’ paper, “Declining patterns of Pacific Northwest steelhead trout (Oncorhynchus mykiss) adult abundance and smolt survival in the ocean,” was published yesterday in the Canadian Journal of Fisheries and Aquatic Sciences.
Until the early 2010s, poor returns had been blamed somewhat nebulously on ocean conditions in the North Pacific, but that tone began to change around 2011 as Puget Sound itself drew increasing scrutiny.
Researchers began considering harbor seals, bridges, diseases and other things that might be behind the declines. Northwest Sportsman and others have been covering that, and this spring an interactive online game put together by Long Live The Kings and called Survive the Sound attempted to bring the problems to a wider audience.
In the reenactment of the migration of 48 tagged smolts that set out from the Nisqually and Skokomish Rivers, only six made it to the open ocean, with most dying in Hood Canal, Puget Sound or the Straits.
True, whether it’s smolts or fawns, a fair portion of any year’s production is going to die, but young and adult Puget Sound steelhead are surviving at much lower rates than they were in the 1980s, with abundances down 77 and 53 percent, respectively, according to a write-up on the paper on Phys.org.
The study is part of the Salish Sea marine Survival Project, which includes steelhead and salmon stocks in British Columbia’s inside waters. Declines seen in Puget Sound steelhead are generally similar to those seen in BC Keogh’s River. Lower Columbia stocks are also suffering.
Puget Sound winter- and summer-run stocks were listed under the Endangered Species Act in May 2007.
Kendall says that if we want more steelhead back in our rivers, we need to figure out what’s killing the young ones as they swim through the Sound, “whether it’s parasites, seal mortality, or not enough food to go around — forage fish, for example,” she says.