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Translocation to the Big Darby Creek in Franklin County, Ohio
The northern riffleshell is an endangered freshwater mussel that was historically found in the Ohio River and Maumee River drainages. Dramatic population declines throughout its range are due to degraded water quality and physical changes to the rivers caused by channelization, dams, and road/bridge construction.
Reintroducing riffleshells to areas where the species has been extirpated, but suitable habitat now exists, and augmenting small populations are essential recovery tools because of the extent of the species' population decline and the fact that remaining populations are isolated from each other. Therefore, the Service took advantage of an opportunity to translocate riffleshells from Pennsylvania for reintroduction and augmentation in Ohio.
A bridge replacement project in the Allegheny River, in Pennsylvania was going to kill or harm over 200,000 federally endangered northern riffleshell mussels so a decision was made to translocate those mussels. When this bridge replacement project was first proposed, a northern riffleshell augmentation and reintroduction plan was already being developed in Ohio and a captive propagation facility was in place at the Columbus Zoo and Aquarium, in cooperation with Ohio State University. With the mussels available for translocation and a plan and facility in place, we decided to translocate mussels from Pennsylvania to augment the small remnant population in the Big Darby Creek as a pilot project to test translocation, captive rearing, and augmentation techniques.
The Northern Riffleshell translocation project took place in the Big Darby Creek within the Battelle Darby Creek Metro Park, Franklin County, Ohio. A few individuals of the Northern Riffleshell remain in the Big Darby Creek in Franklin County, Ohio and suitable habitat still occurs within the Batelle County Metropark. More than 14 miles of the Big and Little Darby creeks run through the Metropark and it is the largest natural area park managed by the Columbus and Franklin County Metropolitan Park District. The Darby creeks are designated state and national scenic rivers and are noted nationally for their tremendous diversity and abundance of both aquatic and terrestrial plants and animals, including forty-three species of freshwater mussels.
Northern riffleshell mussels were collected by Enviroscience, Inc. on the Allegheny River, in cooperation with the Pennsylvania Fish and Boat Commission, the Pennsylvania Ecological Services Field Office (USFWS). The 1,700 northern riffleshell mussels were transported to the Columbus Zoo and Aquarium mussel facility where they were briefly quarantined and fitted with Passive Integrated Transponder (PIT) tags. PIT tags allow biologists to relocate individual mussels in the future and determine the conditions most conducive for long-term survival and reproductive success.
In June, 2008, the northern riffleshell mussels were released in Big Darby Creek. This was the largest single release of any federally listed species in the State of Ohio. Cooperators were the Columbus Zoo & Aquarium, Ohio State University, Ohio Department of Natural Resources Division of Wildlife, Franklin County Metroparks, and the Darby Creek Association. The mussels were placed in existing riffles where remnant populations, darters, and other host fish were known to occur. Information gained from this effort will be directly applicable to future mussel restoration efforts in Ohio as well as throughout the region.
The Big Darby Creek mussel release was the first step in efforts to reintroduce and augment populations with mussels displaced by the bridge replacement. The reintroduction and augmentation will improve resiliency and create better representation and redundancy throughout the range of the species. Focusing our augmentation efforts in Ohio on areas already surrounded by protected uplands within the Big Darby Creek watershed will improve the northern riffleshell opportunity for success.
Although the results of previous translocation efforts for freshwater mussel species have been equivocal, this project allows biologists to monitor the success of the augmentation efforts and to determine the best conditions for reintroduction. Since the release, biologists have visited the sites to monitor the mussels. On both visits, released mussels were found alive in their release sites and the female mussels have begun their reproductive displays, which is an early milestone for the success of the project. However, at least two more years of monitoring will be required to determine whether successful recruitment is occurring. Future releases at other sites throughout the range of the species are being planned using the Strategic Habitat Conservation approach. This will allow for a very carefully selected set of reintroduction and augmentation sites designed to improve resiliency and create redundancy throughout the range of the species thereby increasing the likelihood of survival.
Last updated: January 3, 2013