Stumptown scud: Researchers say small crustacean resides exclusively in Portland waterways

A species of sideswimmer (Ramellogammarus similimanus) freshwater crustacean native to Portland. (OSU)

They're smaller than a pinkie nail, eat dead and decaying material, and look like a cross between a prawn and a potato bug.

But the Stumptown Scud's real claim to fame is that it's only found in and around Portland waterways and nowhere else.

Researchers at Oregon State University -- with funding from the Oregon Zoo Foundation's Fund for Wildlife -- are studying this rare creature and finding where and how they live by tracking small amounts of its leaked DNA.

OSU researcher William Gerth tells us that using this so-called "E-DNA," scientists can estimate the size of the population without having to catch and kill specimens.

“This is the first time anyone has ever studied this organism, so we don’t know how they correlate to the health of the ecosystem,” Gerth said. “The data we’re collecting now will help us track changes in the Stumptown scud’s population, and we hope our study will help management agencies protect this species.”

Gerth said this species of side-swimmer (Ramellogammarus similimanus) is a freshwater crustacean that travels through creeks and tributaries.

The female Stumptown scud carries its eggs in a pouch like a kangaroo, Gerth said, after a complex mating ritual. Males look for female mates who are about to molt out of their shells, and then ride the female piggyback while keeping other potential mates away until she molts.

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