Recovering the Riffleshell: The propagation and translocation of a federally endangered freshwater mussel to Ohio

The Northern Riffleshell, Epioblasma torulosa rangiana, is a federally endangered freshwater mussel. Once common in the Darby Creek system of Ohio, the population experienced a decline in the 1980-1990’s. However, based on the current abundance of other mussels exhibiting recruitment it is believed that the creek has recovered sufficiently to support the Riffleshell again. In August 2007 two trial populations of 23 and 21 individuals were moved from the Allegheny River of Pennsylvania to Big Darby Creek and fitted with passive integrated transponders (PIT) tags. These populations were recovered in October 2007 and July 2008 with only 4% mortality. Based on this trial success, in June and July 2008 1,737 Riffleshells were collected from the Allegheny River, fitted with PIT tags, and moved to Big Darby Creek. Eight individuals died in transit or before release (0.5% mortality). Nine experimental populations were established at six sites within Battelle-Darby Metro Park: two of 500, two of 200, two of 100, two of 50, and one of 69. The 69 individuals had been used for propagation work that resulted in ~700 juveniles that were released as well. The hosts for this propagation (darters) were raised from eggs specifically for the project. Future monitoring will measure the reproductive success of the various-sized populations. It is hoped that these releases will reestablish this unique mussel in Ohio.