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Comparison of conservation strategies for unionids threatened by zebra mussels ( Dreissena polymorpha ): periodic cleaning vs quarantine and translocation

2001; University of Chicago Press; Volume: 20; Issue: 2 Linguagem: Inglês

10.2307/1468315

1937-237X

David E. Hallac, J. Ellen Marsden,

Environmental Toxicology and Ecotoxicology

Native unionid mussel populations have recently declined throughout North America as a result of zebra mussel (Dreissena polymorpha) fouling. Periodic cleaning of fouled unionids and cleaning followed by translocation have been suggested as methods for reducing mortality. Leptodea fragilis and Potamilus alatus were used to determine survival, recovery of energetic stores, and accumulation of newly settled zebra mussels after cleaning and replacement in situ. Both species had high survival, and L. fragilis increased energetic stores after cleaning. Elliptio complanata and Lampsilis radiata were used to compare conservation strategies for unionids fouled by zebra mussels. Survival and glycogen content were used to evaluate stress induced by cleaning and replacement in situ, cleaning and translocation, and cleaning, quarantine, and translocation, relative to the stress in fouled unionids and control (never fouled) unionids. New zebra mussel settlement was assessed to estimate the frequency of cleanings needed. Cleaned E. complanata and L. radiata maintained significantly higher glycogen levels and had higher survival than fouled unionids in all treatments; however, 30% of L. radiata died while in quarantine but no E. complanata died. Translocated unionids were difficult to relocate in the riverine refugium. The inability to find translocated unionids, coupled with high survival and energetic stores in cleaned and replaced unionids, indicate that cleaning and replacement is an effective conservation strategy. Cleaning and replacement may be used as the 1st step to conserve small populations of fouled unionids living in environments where food is not limiting and where collection and cleaning are logistically feasible.