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Upper Midwest Environmental Sciences Center

Aquatic Invasive Species Control

Evaluation of the Acute Toxicity of 3-trifluoromethyl-4-nitrophenol (TFM) to the Snuffbox Mussel (Epioblasma Triquetra)

Principal Investigator: Mike Boogaard

Impact of UMESC Science

The results of this research will allow treatment managers to maintain treatment effectiveness in controlling sea lamprey populations while minimizing the impact to non-target species of concern.   Use of lampricides to control lamprey populations in the Great Lakes is critical to sustaining the Great Lakes fishery industry.


In recent years, there has been growing concern over the risk of lampricide applications to non-target fauna, especially aquatic species listed as threatened, endangered, or of special concern. A number of tributaries that are routinely treated for larval sea lampreys (Petromyzon marinus) also contain populations of the snuffbox mussel (Epioblasma triquetra). Historically, the snuffbox occurred in most of the Great Lakes Basin and the Mississippi River system including 18 states and the province of Ontario, Canada. Current populations are generally separated and genetically isolated from each other by barriers such as impoundments or riverine reaches of unsuitable or otherwise unoccupied habitat (Butler 2006). The snuffbox is now thought to persist in only 40% of its historical range and is considered extinct in Iowa, Kansas, New York, and Mississippi.

The snuffbox is a small triangular shaped mussel found in small to medium-sized creeks to large rivers and lakes. It occurs in swift currents, shoals, and wave-washed lakeshores over gravel and sand with occasional cobble and boulders, generally burrowing deep into the substrate except when spawning or attracting a fish host (Parmalee and Bogan 1998). The reproductive biology of the snuffbox generally follows that of other mussel species.  Males release sperm into the water column where females take up the sperm and filter it through their gills and into the marsupia where fertilization of eggs occurs.  Immature juveniles, known as glochidia, develop in the marsupium and are released by the female into the water column to undergo a period of parasitic encystment within the gills of a suitable host fish species.  Once mature, juveniles drop off and settle into the bottom substrate.

Recent laboratory studies have identified six suitable host fish species for the snuffbox: Iowa darter (Etheostoma exile), logperch (Percina caprodes), rainbow darter (Etheostoma caeruleum), mottled sculpin (Cottus bairdi), largemouth bass (Micropterus salmoides), and brook stickleback (Culaea inconstans) although the logperch is considered the primary host (McNichols and Mackie 2002, 2004).  Snuffbox glochidia are considered morphologically depressed where the valve height is equal to or less than the valve length.  Depressed glochidia are less likely to make contact with a fish host than elongate glochidia due to the smaller valve gape but are more adept to holding on once contact has been made (Hoggarth 1993). Still, the lower rate of recruitment among mussels with depressed glochidia can increase the risk of extinction once numbers of breeding adults are reduced to a critical threshold level.

The snuffbox, like most freshwater mussels, are very limited in their dispersal abilities with adult movement limited to only a few meters on the river/lake bottom. Although movement can be directed upstream or downstream, studies have found a net downstream movement through time (Balfour and Smock 1995, Villella et al. 2004). Therefore, the primary means of large scale dispersal is limited to the encysted glochidial stage on the host fish which could be a contributing factor in the overall declines of snuffbox.

Because of declines nationwide, the U.S. Fish and Wildlife Service (FWS) has recently begun the process of listing the snuffbox as a candidate for the federal endangered species list.  Listing the snuffbox mussel at the federal level could have implications on the successful delivery of the Great Lakes Fishery Commission’s sea lamprey control program.  Streams currently treated with 3-trifluoromethyl-4-nitrophenol (TFM) to control sea lampreys that may be impacted by this listing include the Muskegon, Grand, St. Joseph, Pine, Belle, Saginaw, St. Clair, and Clinton Rivers in lower Michigan and the Grand River in Ohio.

The FWS Ecological Services Office (Lansing, Michigan) has identified a number of toxicological endpoints that need to be evaluated before developing a biological opinion with regard to the lampricide TFM and the snuffbox mussel.

They include:

  1. acute toxicity of TFM to free floating snuffbox glochidia,
  2. acute toxicity of TFM to juvenile snuffbox (2 month),
  3. acute toxicity of TFM to the host fish, the logperch,
  4. success of juvenile recruitment from encysted host fish after TFM exposure,
  5. acute toxicity of TFM to adult ellipse mussels (Venustaconcha ellipsiformis) as a surrogate for the adult snuffbox,
  6. acute toxicity of TFM to juvenile ellipse (2 month) as a comparison to juvenile snuffbox.

Some of these endpoints will require a significant amount of method development before they can be realized.  First, success of juvenile recruitment from encysted host fish after TFM exposure would require a minimum of 18 logperch to be encysted with snuffbox glochidia to successfully evaluate the effects of TFM exposure on juvenile recruitment.  Encystment on such a large-scale has not yet been conducted and additional methods may need to be developed.  Second, although some work has been done on the propagation of the surrogate, the ellipse (Riusech and Barnhart 2000), additional work may be required before sufficient numbers of juveniles can be secured for testing.  In addition, although the ellipse is considered healthy in some regions, removal of significant numbers of adults for testing (200) may not be feasible in the short term. To that end, we propose to evaluate the first three toxicological endpoints identified by FWS Ecological Services, the acute toxicity of TFM to glochidia and juveniles of the snuffbox and the acute toxicity of TFM to the host fish, the logperch.  Evaluation of the other endpoints will be considered under a separate technical assistance proposal once additional propagation and collection methods are developed.


  1. Evaluate the acute toxicity of the lampricide TFM to free floating snuffbox glochidia.
  2. Evaluate the acute toxicity of TFM to 2 month old juvenile snuffbox mussels.
  3. Evaluate the acute toxicity of the lampricide TFM to the host fish of the snuffbox mussel, the log perch.


Balfour, D. L. and L. A. Smock. 1995. Distribution, age structure, and movements of the freshwater mussel Elliptio complanata (Mollusca: Unionidae) in a headwater stream. Journal of Freshwater Ecology 10: 255-268.

Butler, R.S. 2006. Status assessment report for the Snuffbox, Epioblasma triquetra,a freshwater mussel occurring in the Mississippi River and Great Lakes Basins.  A draft report for the Ohio River Valley Ecosystem Team, US Fish and Wildlife Service, Asheville, NC. 234 pp.

Hoggarth 1993. Glochidial functional morphology and rarity in the Unionidae. Pages 76-80 in Conservation and Management of Freshwater Mussels, Proceedings of the upper Mississippi River Conservation Committee Symposium St. Louis, Missouri. Edited by K. S. Cummings, A. C. Buchanan, and L. M. Koch, Illinois Natural History Survey, Champaign Illinois.

McNichols and Mackie. 2002. Fish host determination of endangered freshwater mussels in the Sydenham River Ontario, Canada. ESRF 2002/2003 Final Report. 22 pp.

McNichols, K. and G. L. Mackie 2004. Fish host determination of endangered freshwater mussels in the Sydenham River Ontario, Canada. ESRF 2003/2004 Final Report. 26 pp.

Parmalee, P.W., and A.E. Bogan. 1998. The Freshwater Mussels of Tennessee. The University of Tennessee Press, Knoxville, TN. 328 pp.

Riusech, F. A., and M. C. Barnhart. 2000. Host suitability and utilization in Venustaconcha ellipsiformis and Venustaconcha pleasii (Bivalvia: Unionidae) from the Ozark Plateaus. Pages 83-91 in R. A. Tankersley, D. I. Warmolts, G. T. Watters, B. J. Armitage, P. D. Johnson, and R. S. Butler, editors. Freshwater Mollusk Symposia Proceedings. Part I. Proceedings of the Conservation, Captive Care and Propagation of Freshwater Mussels Symposium. Ohio Biological Survey Special Publication, Columbus, Ohio.

Villella, R. F., D. R. Smith and D. P. Lemarie. 2004. Estimating survival and recruitment in a freshwater mussel population using mark-recapture techniques. American Midland Naturalist 151: 114-133.  Walpole Island Heritage Centre. 2002. Walpole Island First Nation Heritage.

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