ERIE, Pa. — Near midnight at Erie's Lampe Marina, with their first throw of the net, three Penn State Behrend students caught something that had never before been seen in Pennsylvania waters: a tiny, black-eyed shrimp known as Hemimysis anomala.
Though the students were looking for Hemimysis, it shouldn’t have been there — the species, also known as the bloody red shrimp, is native to the Black Sea. It appeared in Lake Ontario in 2006, likely carried in the ballast water from a freighter, and within the year, it had spread to New York’s Oneida and Seneca lakes. The shrimp also were found in the stomach of a perch caught in Port Dover, on the north shore of Lake Erie.
In the years since, Hemimysis had been found in Lake Erie waters near Dunkirk, New York, and Ashtabula, Ohio. Biologists assumed the shrimp also were in Pennsylvania waters, but no one had seen them.
The Behrend students — Kyle Deloe, a senior from Knox; Noel Moore, a sophomore from Lock Haven; and Emily Dobry, a graduate student from Erie — were studying the potential use of environmental DNA, or eDNA, for detecting invasive species. The approach has been useful in the detection and management of other species, including Asian carp.
“It’s traces of DNA, basically, like what you might find at a crime scene,” said Ivor Knight, associate dean for research and graduate studies and a professor of biology at Penn State Behrend. “Hemimysis are small — maybe 2 or 3 mm long — and their bodies are mostly clear, so it isn’t easy to see them in the water. Testing for eDNA could provide evidence that the shrimp are or recently had been in a sample of water.”
Shrimp study
Knight and a colleague, Matthew Gruwell, an associate professor of biology, secured a $177,000 grant from the Great Lakes Protection Fund to study the effectiveness of eDNA in detecting invasive species. They hope to develop a method of quickly testing ballast water in ships that enter lakes that are not yet contaminated.
With help from the student researchers, they set up 24 10-gallon fish tanks and added Hemimysis DNA. In half of the tanks, they added actual shrimp; in the others, they added a slurry — water that had included shrimp, which had since been removed. That allowed them to test how long Hemimysis DNA remains in the water after the shrimp are gone.
To populate the tanks, the team needed Hemimysis, which were shipped, frozen, from a lab in Michigan.
“We needed a lot of them,” Deloe said, “and we were having trouble getting enough. We figured, if we could just go out and collect them ourselves, it would be a lot easier to run the tests.”