COOS BAY — Something is killing large numbers of a keystone species off the Oregon Coast. Federal researchers say it could spell danger for the region’s other marine life.
Bill Peterson, an oceanographer with the National Oceanic and Atmospheric Administration’s Hatfield Marine Science Center in Newport, said in the past few weeks millions of dead North Pacific krill have washed up on beaches between Newport and Eureka, Calif.
Peterson said it’s the largest die-off he’s aware of in recent history.
“The odd thing is that this seems to be happening in both places at the same time,” he said.
The North Pacific species lives largely on the eastern side of the ocean, predominantly between southern California and southern Alaska. Peterson said they’re typically found along the continental shelf.
The shrimp-like crustaceans are an important food source for Chinook and coho salmon in the Pacific Ocean, as well as many other species of birds, fish and marine mammals.
“This is the main food for fish offshore,” Peterson said.
Peterson said researchers currently have two hypotheses about about the cause of the die-offs. The first is hypoxia. “It’s when the oxygen in the water is so low the animals actually get killed by it,” he said.
Peterson said the water temperature right now is low enough that hypoxia wouldn’t be expected.
But, tests have returned unexpected results.
Joe Tyburczy, a researcher with the California Sea Grant extension office who has been looking into the dead krill with Peterson, said oceanographic cruises along the northern California coast did find lower oxygen levels than usually seen in Pacific Northwest waters.
“If it is hypoxia, there’s a possibility of implications for other species like crab,” he said.
Another possibility is that the krill could have experienced unfriendly weather conditions during their mating cycle.
“This particular species live in really quite shallow water,” Peterson said. “When they reproduce, they get into these really huge swarms.”
The oceanographer said recent high winds may have driven the shrimp to shore.
For the moment, Peterson and Tyburczy are depending on the public to be their eyes on the sand.
“If this happens again,” Peterson said. “I’ll have to take a drive down the coast.”
Reporter Thomas Moriarty can be reached at 541-269-1222, ext. 240, or by email at firstname.lastname@example.org. Follow him on Twitter: @ThomasDMoriarty.