LONG CREEK, OR. – The North Fork John Day Watershed Council’s (NFJDWSC) intensive monitoring efforts on the Middle Fork of the John Day River have collected an invasive species, previously un-recorded in eastern Oregon or the John Day River system. The “European ear snail” was collected by NFJDWC Project Coordinator, Valeen Madden, on September 24, 2014 in a drift net during regular macroinvertebrate monitoring activities on the Middle Fork John Day River. The European ear snail was positively identified in the drift net sample by Rithron Laboratories of Missoula, MT.
European ear snails (Radix auricularia) are in the family of lymnaeid snails which are scrapers and gatherers. They are native to both Europe and Asia. The species generally grow to about 15 mm in height and 13 mm in width. The mantle has dark spots along its edge and 4 to 5 whorls in the shell. The snails generally prefer fresh water lakes and slow moving rivers. Ear snails feed on detritus, algae, and sand. Their common name is derived from the “ear” shaped shell in which they live.
The European ear snail is not considered a “noxious” species, only an invasive species. That indicates that the snail is exotic to North America, and it is increasing its population density, but it is not outcompeting or having any detrimental effect on native species in the lakes and rivers where it is found. The nearest prior discovery to the west was in Lake Billy Chinook in central Oregon and to the east in Idaho’s Snake River and Owyhee drainages. Significant populations occur in southwestern Oregon.
The NFJDWC will seek additional funding to search upstream and downstream from the capture site to determine the level of prevalence of the population. Additional investigation by the Oregon Department of Fish and Wildlife Invasive species coordinator will seek to determine the source of the new species. Elaine Eisenbraun, Executive Director of the NFJDWSC, stated, “Rivers are such a dynamic element of our environment. It is important to keep an eye on the changes that take place naturally and as a result of human activity. Our staff is working diligently to gather relevant information about the health and constant changes in the waterways that we monitor. It is a tribute to the diligent work of our monitoring staff that their efforts revealed a critical change in the system biota.”
For more information:
Elaine Eisenbraun, Executive Director
North Fork John Day Watershed Council
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