Millions of krill—tiny shrimp-like animals that are food for salmon, whales and other large marine species—have been washing up on beaches from Bodega Bay, Calif. to Newport, Ore. in recent weeks.
Joe Tyburczy, a California Sea Grant Coastal Specialist in Eureka, is trying to figure out why, with colleagues from NOAA, Humboldt State University and Oregon State University.
Possible explanations currently under study include:
Winds. Mating swarms of krill at the surface may have been pushed ashore by strong storm winds.
Low-oxygen waters may have contributed to the mortality event by driving masses of krill to shallower-than-normal waters, where oxygen levels are higher, but the animals are also more vulnerable to wind-driven currents.
A krill pathogen or parasite could have played some role. Some krill have washed up alive, and there have been many reports of surprisingly little predation by birds.
Tyburczy has been gathering a variety of data from colleagues to help assemble a coherent picture of the conditions that might explain the krill deaths.
“The krill die-off is a puzzle,” Tyburczy said. “We can solve it only if we make use of ongoing, long-term monitoring data. It’s the monitoring data that can tell us what the ocean conditions were before, during and after the krill die-off.”
Some of his collaborators on the project are:
Bill Peterson, a NOAA oceanographer and krill expert, who is studying krill samples
Eric Bjorkstedt, a NOAA oceanographer, who has survey data on offshore krill abundances and ocean conditions in Northern California
Frank Shaughnessy, a Humboldt State University professor, who collects regional weather and ocean data as part of the CeNCOOS (Central and Northern California Ocean Observing System) program, and
Francis Chan and Jack Barth, Oregon State University researchers, who are sharing coastal ocean monitoring data collected through the PISCO (Partnership for Interdisciplinary Studies of Coastal Oceans) program.
The krill mortality event was first reported by The World. An Associated Press article has since been syndicated in several West Coast newspapers.
Key Species Mysteriously Dying off Oregon Coast – The World
Millions of krill wash up on Ore., Calif. beaches – San Diego Union Tribune
Please contact Joe Tyburczy at firstname.lastname@example.org if you find krill washed up on local beaches. Please include the date, specific location, and if possible, a close-up photo of the krill and a photo that shows the full extent of the krill patch along the shore.
Written by Christina S. Johnson