A parasitic isopod known as Orthione griffenis is decimating mud shrimp populations in coastal estuaries ranging from British Columbia to northern California. Most surviving mud shrimp populations are heavily infested with the parasite, threatening their existence.
“From Bamfield, Canada, down to Morro Bay, California, the native mud shrimp, Upogebia pugettensis, are either gone or the populations are severely depressed,” said John Chapman, an Oregon State University invasive species specialist who works out of OSU’s Hatfield Marine Science Center in Newport.
Mud shrimp are valuable prey for birds, fish and other animals in estuaries, and some ecologists believe they have provided a steady food source for ocean-bound juvenile coho and Chinook. Mud shrimp are also important to the ecology of estuaries: each day during their feeding, they may filter as much as 80 percent of the estuary’s intertidal water.
Studying the shrimp, which can burrow to depths of two meters, involves extracting them with quantitative sampling devices. These devices traditionally have been either handheld cores and shovels, which can damage the shrimp beds, or a “yabby” pump, which sucks up only medium-sized and large shrimp and is not quantitative. Neither method is reliable for quantifying the most important reproductive sizes, and both often damage shrimp in the process of collecting them.
The solution? Create a new device that’s not only long enough to reach the deepest shrimp, but gentle enough to bring them to the surface unharmed — and also simple enough to allow for rapid, inexpensive sampling by just a few researchers.
Engineering student Cade Burch demonstrates his team’s “portable deep core.” (Photo by Rick Cooper)
To develop the device — a “portable deep core” — Chapman enlisted the assistance of OSU Engineering professors John Parmigiani and Sharon LaRoux, who would oversee the student design teams* and participate in the field testing and implementation. Chapman and Parmigiani also secured $9,000 in funding from Oregon Sea Grant, to help defray materials costs and other expenses.
Between January and May 2017, three student teams, each working on a different design, researched, planned, designed, built and tested the components of their respective devices, and on May 19 they unveiled the working prototypes at OSU’s Undergraduate Engineering Expo. “Each of the three designs will be evaluated and combined over the summer by a graduate student into a single, final prototype,” said Parmigiani.
According to Chapman, the newly designed deep core “will, for the first time, give us access to the entire range of burrowing shrimp populations, and let us gather the information we need to help slow or reverse the mud shrimp’s decline.”
205a: Cade Burch, Eric Beebe, Omar Alkhaldi
205b: Patrick Finn, Jacob Garrison, Connor Churchill
205c: Zachary Gerard, Evan Leal, Derrick Purcell
Additional reporting by Mark Floyd, OSU News and Research Communications