If you noticed a strange sight along the Edmonds shoreline this week, you aren’t alone. The City of Edmonds investigated this deposit, which washed up on the beach Tuesday morning, and discovered it consisted of larval crabs called zoea.
“After hatching from eggs, crab take on a pelagic larval form called zoea, passing through several stages before settling out as the form we recognize as a crab, said the City’s Environmental Education and Sustainability Coordinator Jennifer Leach. “Zoea float with the currents and tides and occasionally wash up on shore.
“Following what we assumed was a mass local spawning event, trillions of zoea were deposited by a receding tide along the Edmonds shoreline on Tuesday, April 19.”
Leach said this a normal, although rare, occurrence. According to the Washington State Department of Fish and Wildlife, they are likely Dungeness crab zoea, she said.
The city collected samples, and then contacted Washington State Department of Fish and Wildlife shellfish biologist Don Rothaus, who came to Edmonds Thursday so he could take a sample back to his lab.
According to the Rothaus, “this is just a case where freshly molted zoea larvae somehow were rafted into a large mass and windrowed up on the receding high tide.”
The City of Edmonds has posted signs along the beach that explain the zoea deposits, said Parks, Recreation and Cultural Services Director Carrie Hite.