Status assessment report for the snuffbox, Epioblasma triquetra, a freshwater mussel occurring in the Mississippi River and Great Lakes Basins Prepared by Robert S. Butler U.S. Fish and Wildlife Service 160 Zillicoa Street Asheville NC 28801 for the Ohio River Valley Ecosystem Team Mollusk Subgroup July 2007 TABLE OF CONTENTS Disclaimer ...................................................................................................................................... 2 Common name ............................................................................................................................... 4 Scientific name .............................................................................................................................. 4 Controversial or unsettled taxonomic issues .............................................................................. 4 Physical description of the taxon ................................................................................................. 5 Summary of biology and natural history .................................................................................... 6 Feeding ecology .......................................................................................................................... 6 Growth and longevity .................................................................................................................. 7 Reproductive biology .................................................................................................................. 8 From parasitic glochidia to free-living subadults .................................................................... 10 Habitat requirements .................................................................................................................. 12 Historical and current range ...................................................................................................... 12 Methods .................................................................................................................................... 13 Historical range ........................................................................................................................... 12 Current distribution ................................................................................................................... 16 Extant populations by state ....................................................................................................... 16 Current and historical populations, and population trends ................................................... 17 Upper Great Lakes sub-basin ................................................................................................... 20 Lower Great Lakes sub-basin ................................................................................................... 24 Upper Mississippi River sub-basin ........................................................................................... 32 Lower Missouri River system .................................................................................................... 36 Ohio River system ..................................................................................................................... 36 Cumberland River system ......................................................................................................... 60 Tennessee River system ............................................................................................................. 61 Lower Mississippi River sub-basin ........................................................................................... 66 White River system .................................................................................................................... 67 Summary of current and historical populations, and population trends .................................. 70 Summary of status and threats .................................................................................................. 73 A. The present or threatened destruction, modification, or curtailment of its habitat or range. .................................................................................................................................... 73 Impoundments ....................................................................................................................... 73 Channelization ...................................................................................................................... 77 Contaminants ........................................................................................................................ 78 Mining ................................................................................................................................... 82 Sedimentation ........................................................................................................................ 85 Other activities ...................................................................................................................... 87 B. Overutilization for commercial, recreational, scientific, or educational purposes. ..... 89 C. Disease or predation. .......................................................................................................... 89 D. The inadequacy of existing regulatory mechanisms. ...................................................... 91 E. Other natural or manmade factors affecting its continued existence............................ 91 Population fragmentation and isolation ............................................................................... 92 2 Genetic considerations .......................................................................................................... 92 Alien species .......................................................................................................................... 93 Current protective status under state/provincial/tribal/Federal laws and regulations ........ 96 Summary of land ownership and existing habitat protection ................................................. 96 Past, current, and anticipated conservation activities undertaken for the benefit of the species or its habitat ............................................................................................................... 97 Management actions (species, habitat, or people management) needed .............................. 101 Research, surveys, and monitoring needed ............................................................................ 103 Status assessment summary ..................................................................................................... 103 References ..................................................................................... Error! Bookmark not defined. Name and office of preparer(s) and the date prepared ......................................................... 156 List of primary individuals contacted. .................................................................................... 156 FIGURE 1 .................................................................................................................................. 157 APPENDIX I ............................................................................................................................. 159 APPENDIX II ............................................................................................................................ 195 APPENDIX III .......................................................................................................................... 200 APPENDIX IV........................................................................................................................... 204 Title page photo credit—Ronald R. Cicerello and Guenter A. Schuster (male on top, female on bottom) (from Cicerello and Schuster 2004) 3 Disclaimer This document is a compilation of biological data and a description of past, present, and likely future threats to the snuffbox (Epioblasma triquetra). It does not represent a decision by the U.S. Fish and Wildlife Service (Service) on whether this taxon should be designated as a candidate species for listing as threatened or endangered under the Federal Endangered Species Act (Act). That decision will be made by the Service after reviewing this document; other relevant biological and threat data not included herein; and all relevant laws, regulations, and policies. The result of the decision will be posted on the Service's Region 3 Web site (refer to: http://midwest.fws.gov/eco_serv/endangrd/lists/concern.html). If designated as a candidate species, the taxon will be added subsequently to the Service's candidate species list that is published periodically in the Federal Register and posted on the World Wide Web (refer to: http://endangered.fws.gov/wildlife.html). Even if the taxon does not warrant candidate status it should benefit from the conservation recommendations that are contained in this document. Common name: snuffbox Scientific name: Epioblasma triquetra Controversial or unsettled taxonomic issues The snuffbox is a member of the freshwater mussel family Unionidae and was described as Truncilla triqueter Rafinesque, 1820. The specific epithet was later emended to triquetra, from the Latin triquetrous meaning “having three acute angles” (Simpson 1900), a reference to the general shape of the female. The type locality is the Falls of the Ohio (Ohio River, Louisville, Kentucky)