Bigmouth shiner (Notropis dorsalis) COSEWIC assessment and status report: chapter 6

Distribution

In summary, the distribution of the bigmouth shiner includes the Hudson Bay (Red River), Great Lakes and Mississippi River basins from northern Michigan to southern Manitoba, and from eastern Illinois to the Platte River system, eastern Wyoming and northern Colorado. There are disjunct populations in western New York and Pennsylvania, western Michigan, northern Ohio, and northern West Virginia (Page and Burr 1991), and in western Tennessee (Etnier and Starnes 1993) (Figure 2). Three subspecies have been recognized. Notropis d. piptolepis is native to the Platte River system in Wyoming and Colorado; N. d. keimi is native to Lake Ontario and Allegheny River drainages in New York and Pennsylvania; and N. d. dorsalis is throughout the rest of the range (Page and Burr 1991).

In the original status report, Tompkins (1985) described the distribution of the bigmouth shiner in the United States in great detail. This will not be repeated for this update, as no recent updated information exists in the published literature.

At the time of the publication of the original status report, Tompkins (1985) identified the Canadian distribution of the bigmouth shiner as the Pembina River (Red River tributary) in southern Manitoba near the border with the United States, and the Woody and Roaring rivers, which flow into Swan Lake (Figure 2 in Tompkins 1987). Fedoruk (1970) first reported the bigmouth shiner in Canada from the Pembina River after collecting 84 specimens at five locations in 1968. 


Figure 2: North American Distribution of the Bigmouth Shiner, Notropis dorsalis

Figure 2: North American distribution of the Bigmouth Shiner, Notropis dorsalis.

From Page and Burr (1991) and Etnier and Starnes (1993).

The Pembina River location records from Fedoruk (1970) and Copes and Tubb (1966) are illustrated in Figure 3 in Tompkins (1987). The collections made by Copes and Tubb (1966) were from the United States portion of the Pembina River watershed. The Woody and Roaring River specimens in the collections of the Royal Ontario Museum were originally identified as mimic shiners (Notropis volucellus) and erroneously illustrated in the distribution maps for that species in Scott and Crossman (1979) (K.W. Stewart, pers. comm. 2003). The mimic shiner is restricted to tributaries east of the Red River in southeastern Manitoba (K.W. Stewart pers. comm. 2003).


Figure 3: Canadian Distribution of the Bigmouth Shiner, Notropis dorsalis

Figure 3: Canadian distribution of the Bigmouth Shiner, Notropis dorsalis.

Black circles indicate localities from original status report (Tompkins 1985). Gray circles indicate new locality records.

Since the original status report was published, the distribution of the bigmouth shiner has not been expanded latitudinally, but is more extensive, as the species has been collected from the Cypress, Shell, Little Saskatchewan, and Assiniboine rivers, as well as Oak and Epinette Creeks. The species also has been found in the lower Roseau River near its junction with the Red River (Figure 3). Twenty-seven individuals were collected there by the author, Dave Tyson, and Gavin Hanke in May 1991. The bigmouth shiner was first recorded in the Assiniboine River in 1979 at the Provincial Highway 34 crossing (Stewart et al. 1985); in the Little Saskatchewan River near its junction with the Assiniboine River in 1954; in the Cypress River at the Provincial Highway 2 crossing in 1985; and from the Shell River in 1953 (Appendices 1, 3-5 in McCulloch and Franzin 1996). The bigmouth shiner was first recorded from Oak Creek in 1973 and from Epinette Creek in 1989 (Appendix 7 in McCulloch and Franzin 1996). While range extensions of species such as the stonecat (Noturus flavus) (McCulloch and Stewart 1998) and rainbow smelt (Wain 1993) in Manitoba reflect recently invading species (the stonecat naturally via high meltwater conditions between headwaters of Red River and upper Mississippi drainages; and the rainbow smelt (Osmerus mordax) through bait bucket transfers), the bigmouth shiner appears to have dispersed into Manitoba with the retreat of the Wisconsinon glaciation.

The presence of the bigmouth shiner in the Shell and Little Saskatchewan rivers upstream of the Shellmouth and Rivers dams respectively, both of which have halted the stonecat’s dispersal in these rivers (McCulloch and Stewart 1998), supports the bigmouth shiner’s lengthy presence in Manitoba. Absence of the species in the Souris River, despite extensive collections made by Hallum’s group from the Manitoba Museum of Man and Nature in 1974, and by a research group led Dr. Bill Franzin of the Department of Fisheries and Oceans in 1995, may be explained by the lack of suitable habitat due to alterations to stream flow and discharge in the form of check dams throughout much of the river’s length. Possibly, this has eliminated any long stretches of relatively shallow, monotypic habitat preferred by the species.

The bigmouth shiner is most likely present in other streams in western Manitoba. Its present distribution in Manitoba is reflected by the relative lack of collection effort in this region of Manitoba. While yearly September collections throughout the 1980s and most of the 1990s by Dr. Ken Stewart and the Biology of Fishes Class at the University of Manitoba have contributed greatly (almost single-handedly) to the determination of fish distribution in southern Manitoba, time constraints on the weekend field trips usually restricted collection efforts within the Assiniboine River watershed from the city of Winnipeg west to near the city of Brandon and north to the Little Saskatchewan River.

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