COSEWIC Assessment and Update Status Report on the Redside Dace in Canada
- Assessment Summary
- Executive Summary
- COSEWIC History, Mandate, Membership and Definitions
- Lists of Figures, Tables and Appendices
- Species Information
- Population Sizes and Trends
- Limiting Factors and Threats
- Special Significance of the Species
- Existing Protection or Other Status Designations
- Technical Summary
- Acknowledgements, Authorities Contacted, and Information Sources
- Biographical Summary of Report Writers and Collections Examined
- Appendix: Results of Early and Recent Sampling in Canadian Watersheds (Tables 1 - 22)
The global range of the redside dace is discontinuous (Fig. 2). It is found in streams of all five of the Great Lakes, the Susquehanna River, the Ohio River, and the upper Mississippi River drainages. It occurs in a wide band starting from northcentral New York continuing southwest through Maryland and West Virginia, west to Kentucky and north to Indiana, Ohio, Michigan and Ontario, where it was recently discovered in the Two Tree River, a northern Lake Huron tributary near the outlet of Lake Superior. In the west, this species is found primarily in Wisconsin, but populations also have been documented in the surrounding states of Minnesota, Illinois (Sabaj 2001) and Iowa. The most northerly population is in the upper peninsula of Michigan, where it was first discovered in 1998 in the Lake Superior drainage (Latta 1998). Bailey et al. (2004) suggest that this is an introduced population. Conservation Data Centres in range jurisdictions of the United States were contacted in 1997 regarding trends in the range and population abundance of redside dace. The species has been extirpated from two states (IA, MD), has experienced range reductions in at least two states (MI, OH) and was reported as having a stable range in three states (KY, IN, PA). Four jurisdictions did not have information with respect to changes in range (NY, WI, MN, WV).
The current Canadian distribution of redside dace is approximately 5% of the global range, and is limited to small, isolated populations in southern Ontario (Fig. 3 and 4). Most populations occur in tributaries to western Lake Ontario from Pringle Creek (west of Oshawa )in the east to Spencer Creek (northwest of Hamilton) in the west (Fig. 3). Populations are also known from the Lake Simcoe drainage (Holland River system), the Lake Erie drainage (Irvine Creek), and the Lake Huron drainage (Saugeen River system, Gully Creek and the Two Tree River) (Parker et al. 1988; Mandrak and Crossman 1992; ROM 2005). Details regarding trends in the Canadian range of redside dace are discussed in more detail under ‘Fluctuations and Trends’ in the Population Sizes and Trends section.
The redside dace was once found in small (< 10 m wide), isolated tributaries of 24 watersheds in Ontario. The redside dace was most likely extirpated from seven watersheds between 1940 and 1980. Although one population (Humber River) appears to have undergone a range expansion between 1950 and 1980, most of the populations in the remaining 16 watersheds have been restricted to, or become fragmented into, small isolated sections of an earlier, wider distribution. There is recent (2000-2004) sampling evidence that two of these populations (West Don River and Morrison Creek) are close to extirpation, or have been extirpated, and some populations such as that in the Saugeen River, have undergone range reductions of greater than 90%. Populations have also been apparently extirpated from portions of the Humber River, Credit River and Duffins Creek watersheds. Although the overall extent of occurrence in Canada has declined slightly (estimated at 46 900 km2 from Fig. 2), the area of occupancy [estimated at less than 4 km2 based on occupied stream length X steam width as determined from 1:50 000 (topographic maps), or as 441 km2 (based on overlaid grids of cell size one km2, total AO is the number of occupied squares that are intersected by streams)] has declined significantly (Table 1).
Map based on Gilbert 1980, updated with data from Lyons et al. 2000, MDNR 2004, Mandrak 2003, Cooper 1983, Meade et al. 1986, and NYDEC 2004. Global (930 000 km2) and Canadian: (46 900 km2). Extent of occurrences are outlined.
Unverified specimens that may represent misidentifications have been reported from Graham Creek, a Spencer Creek tributary (Fletcher Creek), and a tributary of Twenty Mile Creek (Lake Ontario drainage); upper Grand River near Belwood Lake (GRCA 1996), Nith River and Washington Creek (Grand River drainage) (Taylor 1988); Cobourg Creek (Lake Erie drainage); a creek near Sebringville (Thames River drainage); a Teeswater tributary, Greenock Creek (Saugeen River drainage); and Holmesville Creek (Maitland River drainage). Data are lacking to substantiate Coad’s (1995) statement that the redside dace has dispersed outside its natural range in southern Ontario as a bait fish (Coad pers. comm. 2003).
Based on Holm and Andersen (2005).
Based on Holm and Andersen (2005).
|Drainage and stream||Trend in range Increase||Trend in range Stable||Trend in range Decline||Trend in range Extirpated||Comments|
|Pringle Creek||X||X?||May be extirpated|
|Lynde Creek||X||Small range reduction|
|Duffins Creek||X||X?||May be extirpated from two tributaries and main stem|
|Petticoat Creek||X||X?||Probably extirpated (not collected since 1954)|
|Highland Creek||X||Last seen in 1952|
|Rouge River||X||Remains widespread in watershed, small range reduction|
|Don River||X||Large range contraction|
|Humber River||X||X||X||Range expansion in West Humber, stable in east Humber, contraction in main stem|
|Mimico Creek||X||Last seen in 1949|
|Etobicoke Creek||X||Last seen in 1949|
|Clarkson Creek||X||Last seen in 1927|
|Credit River||X||X||Extirpated from Levi’s creek, range reduction in Silver Creek.|
|Morrison Creek||X||X?||May be extirpated|
|Sixteen Mile Creek||X||Small range reduction|
|Fourteen Mile Creek||X||Small range reduction|
|Bronte Creek||X||Large range reduction|
|Spencer Creek||X||Large range reduction|
|Niagara area stream||X?||Probably extirpated – last seen in 1960|
|Holland River||X||Large range reduction|
|Irvine Creek||X||Large range reduction|
|Gully Creek||X?||Presumed stable|
|Saugeen River||X||94% range reduction|
|Two Tree River||X?||Presumed stable|
The information on range and population trends comes from a database maintained by the Redside Dace Recovery Team (Holm and Andersen 2005) consisting of 644 records of redside dace captures and 364 attempts at former sites of occurrence.
- Date Modified: