Sharing estuary parasite data

Posted January 2006

Courtesy of Fisheries and Oceans Canada’s “StreamTalk”, Fall 2005

Dr. John Chapman, a professor of fisheries and wildlife at Oregon State University, heads the Biological Invasions Program at the university's Hatfield Marine Science Center in Newport. He is asking for data from north-of-49 estuaries regarding the parasitic bopyrid isopod, Orthione griffenis. It infests the gill chambers of the blue mud shrimp Upogebia pugettensis. Preliminary studies indicate that the parasite may be interfering with shrimp reproduction.

As a food source for other animals and as water filterers, shrimp are vital to estuary health. Chapman and his colleagues are seeing a population explosion of the parasite, which they suspect has been introduced in bilgewater from Asian freighters. High school students surveyed the Upogebia in all estuaries in Lincoln County, Oregon this summer as part of a Summer Natural Resources program. The crews found intense infestations in every estuary.

“Concern over ‘crying wolf’, or otherwise overstating the significance of new invaders is understandable,” says Chapman. “However, initial reactions to the New Zealand mudsnail, Spartina, Undaria, milfoil, ivy, the green crab, the mitten crab, and to most nonindigenous aquatic species that became pests have mostly been too little too late. A better response may be to react to the data at hand, which says Orthione is an invader. A good reaction might be to encourage research immediately. Better knowledge would place managers and the public at greater advantage to decide what (if anything) can be done to prevent its further national and international spread, to learn from and to mitigate for its effects.”

Chapman says that little is known about Orthione in Puget Sound and the Strait of Georgia or along the coasts of B.C. and Alaska. Information on the distribution and timing of early sightings of this isopod in the northeast Pacific would help determine the source and rapidity of the infestation.

To view photos of the blue mud shrimp and the parasitic isopod click here.

Dr. Chapman can be reached through the Oregon State University at