Etheostoma chlorosoma (Hay, 1881)
Basis for Listing
The Bluntnose Darter (Etheostoma chlorosoma) was listed a special concern species in 1984 because it had not been collected in Minnesota since 1949. In 1996, following extensive surveys of its very restricted range in the Mississippi River in southeastern Minnesota (Schmidt 1991; Stopyro 1995; LTRMP 2013), the species was presumed extirpated and removed from the list. Then, in 1997 a single specimen was collected from Pine Creek near La Crescent (Houston County), and in 2001 another was collected from a Mississippi River backwater at Winona (Winona County) (Schmidt 2012). A State Wildlife Grant Program (SWG) project (Schmidt and Proulx 2009) and continuing DNR Long Term Resource Monitoring Program (LTRMP) surveys have failed to find additional specimens. The Bluntnose Darter is Minnesota’s rarest fish species; here, at the northern periphery of its range, its long-term survival is very much in doubt. Therefore, it was once again listed as a special concern species in Minnesota in 2013; it has been listed as endangered in Wisconsin since 1979 (WI DNR 2013) and in Iowa since 2009 (IA DNR 2013).
The Bluntnose Darter is a small darter that is usually 3.5-5.0 cm (1.4-2.0 in.) total length and may attain a maximum size of 6.5 cm (2.6 in.). Its body is long and slender, marked with irregular thin brown blotches on the sides. The head is small, with a short very blunt snout baring a black stripe on either side. The mouth is subterminal. Live specimens are sometimes translucent and may be light greenish yellow in color. The species is easily confused with Least Darters (E. microperca) and Johnny Darters (E. nigrum). Distinguishing characteristics of the Bluntnose Darter include a continuous dark strip over snout, lobes of dorsal fin separated, and a lateral line scale count of 52-58 (Lyons et al. 2006).
In Minnesota (Blufflands Subsection), the species has been found in floodplain habitats of the Mississippi River, such as backwaters and ponds with little or no current. The 1997 locality in Pine Creek was a small low gradient stream with a silt-sand substrate. The specimen was collected along a cattail (Typha sp.) edge void of submerged vegetation. The 2001 site was a shallow and sparsely vegetated shelf along a backwater channel (Schmidt 2012). The collection was made in November; however, during the summer, beds of wild celery (Vallisneria americana) lined the outer edge of the shelf, which consisted of sand and mud substrates. Dropping off into a deeper channel, the substrate changed to clay, which was littered with detritus and twigs. (R. Katula, pers. comm.).
Biology / Life History
There is very little life history information available on this species. Thought to reach sexual maturity at age-1, the Bluntnose Darter spawns in April and May in Illinois. It attaches its eggs to aquatic plants, dead leaves, and organic debris. Males engage in aggressive territorial displays and flashy courtship; it has a lifespan of 2-3 years (Etnier and Starnes 1993). Although no comprehensive food studies have been made, they are known to eat immature aquatic insects and microcrustaceans (Etnier and Starnes 1993).
Conservation / Management
Research needs include life history and genetic studies. Due to the species rarity, surrogate populations will have to be identified south of Minnesota, where an adequate sample size of specimens can be obtained.
Conservation Efforts in Minnesota
The bulk of potentially suitable Bluntnose Darter habitat is protected within the boundaries of the Upper Mississippi River National Wildlife and Fish Refuge. The recent inception of Minnesota’s Clean Water Legacy Program will eventually yield benefits to Bluntnose Darter habitats through sediment load reductions.
References and Additional Information
Becker, G. C. 1983. The fishes of Wisconsin. University of Wisconsin Press, Madison, Wisconsin. 1052 pp.
Coffin, B., and L. Pfannmuller, editors. 1988. Minnesota's endangered flora and fauna. University of Minnesota Press, Minneapolis. 473 pp.
Etnier, D. A. and W. C. Starnes. 1993. The fishes of Tennessee. University of Tennessee Press, Knoxville, TN. 681 pp.
Gilbert, C. R. 1980. Etheostoma chlorosomum (Hay) Bluntnose Darter. Page 634 in D. S. Lee, C. Gilbert, C. Hocutt, R. Jenkins, and McAllister. Atlas of North American Freshwater Fishes. North Carolina Museum of Natural History, Raleigh. 854 pp.
Iowa Department of Natural Resources. 2013. Iowa's Endangered and Threatened Species List [web page]. Iowa Department of Natural Resources, Des Moines. <http://www.iowadnr.gov/Environment/ThreatenedEndangered.aspx>. Accessed 14 May 2013.
Long Term Reasource Monitoring Program (LTRMP). 2013. Mississippi River pools 4 and 8 fish survey data (1989-2015). LTRMP Fisheries Data, Graphical Fish Database Browser [web application]. Upper Midwest Environmental Sciences Center, USGS, La Crosse, Wisconsin. <http://www.umesc.usgs.gov/data_library/fisheries/graphical/fish_front.html>. Accessed 11 April 2013.
Lyons, J., P. C. Hanson, E. A. White. 2006. A photo-based computer system for identifying Wisconsin fishes. Fisheries 31(6):269-275.
Minnesota Department of Natural Resources, Fisheries. 2013. Mississippi River pools 3-9 fish survey data (1986-2013). Minnesota Department of Natural Resources, St. Paul. Data set received 8 May 2013.
NatureServe. 2009. NatureServe Explorer: an online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington Virginia. <http://www.natureserve.org/explorer>. Accessed 03 August 2009.
NatureServe. 2013. NatureServe Explorer: an online encyclopedia of life [web application]. Version 7.1. NatureServe, Arlington Virginia. <http://www.natureserve.org/explorer>. Accessed 11 April 2013.
Schmidt, K. 2012. NANFA Members Search for Minnesota's Rarest Fishes. American Currents, 37(4) 2-7: , Fall 2012.
Schmidt, K. P. 1991. Stream survey results for the Slender Madtom (Noturus exilis), Crystal Darter (Ammocrypta asprella) and Bluntnose Darter (Etheostoma chlorosomum) in southeastern Minnesota. Final report submitted to the Natural Heritage and Nongame Research Program, Minnesota Department of Natural Resources. 12 pp.+ appendices.
Schmidt, K. P., and N. Proulx. 2009. Status and critical habitat of rare fish species in the Mississippi River from the Coon Rapids Dam to the Iowa border. Final report submitted to the State Wildlife Grants Program, Minnesota Department of Natural Resources. 29 pp.
Stopyro, M. 1995. Nongame fish survey data of the Mississippi River from Minneapolis to the Iowa border (unpublished). Minnesota Department of Natural Resources, Lake City, 95010001-95010120.
Wisconsin Department of Natural Resources. 2013.. Wisconsin's endangered and threatened species list [web page]. Wisconsin Department of Natural Resources, Madison. <http://dnr.wi.gov/topic/endangeredresources/etlist.html>. Accessed 09 May 2013.