Brace yourself, Seaside. It's about to get smelly.
Thousands of dead anchovies washed ashore along the Necanicum River in downtown Seaside on Monday.
The anchovies entered the river en masse from the Pacific Ocean and, unfortunately for the fish, there was only so much oxygen to go around.
"There's just so many fish in this little tiny river that they deplete the oxygen and some of them start to die," said Tiffany Boothe, of the Seaside Aquarium.
The unusually large anchovy run started to line the river after high tide Monday night.
"I saw thousands of fish and I thought, 'That's sad. What's happened?'" said Penny Russell, who was visiting the coast from Portland. "I've never seen anything like this before."
For Oregon Coast tourists, it made for a unique sight. For birds, it made for a feeding frenzy.
"The birds love it. It makes for great birdwatching. We've got tons of pelicans in the area now," Boothe said. "It's a really healthy thing for the birds."
Large anchovy die-offs are "a naturally occurring thing," Boothe said.
"It's going to smell for a couple days probably while these guys make their way back out to the ocean," she said.
Aquarists at the Oregon Coast Aquarium said anchovy die-offs like this one are a fairly normal occurrence and are no cause for alarm. They said the issue started before the anchovies reached the river.
"Over the last few days, our part of the coast has seen a seasonal upwelling, which means there is an increase of nutrients in the water," they said.
The nutrients led to a big increase in the population of phytoplankton, which then creates a major bloom that decreases the water's dissolved oxygen at night and slightly decreases its pH.
"The overall change in water quality is often detrimental to localized, high energy schooling fish such as anchovies," Oregon Coast Aquarium aquarists said. "They were weakened and at the mercy of the tide, which brought them up during the high tide."
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