Cannon Beach Police advised beachgoers this week of shark dorsal fin sightings in the Cannon Beach area.
They also announced state parks would be posting warning signs on local beaches.
Shark sightings off the Oregon coast are not uncommon this time of year. As salmon swim back to the shore in the summer, so do their predators.
“Sharks — especially those that feed on salmon — will follow their prey, which is generally the salmon stocks, closer to shore,” said Lynn Mattes, a fishery biologist and manager for the Marine Resources Program with the Oregon Department of Fish and Wildlife.
Mattes also said climate change and warmer oceans influence where fish and their predators end up.
“A lot of fish — both the prey and predator species — have ideal temperature ranges where they like to be,” she said. “If there’s temperature changes to the ocean, that could influence where the fish are and where the sharks are.”
In her almost nine years as a fishery biologist with the department, Mattes said shark sightings have remained pretty constant.
People also frequently ask questions about why sharks eat people. Don't worry, there's good news: Humans are not a shark’s prey of choice.
“Most of the time it’s misidentification,” Mattes said. “It’s not that the shark is trying to attack people, it’s going after its prey and made a mistake.”
The beaches will remain open. The advisory signs will stay up for several weeks.
Copyright 2017 Oregon Public Broadcasting
