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COSEWIC Assessment and Update Status Report on the Redside Dace in Canada


Global Range

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).

Canadian Range

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. Figure3 and Figure4). 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).

Figure 2: Global Range of the Redside Dace

Figure 2: Global range of the redside dace.

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).

Figure 3: Distribution of Redside Dace in the “Golden Horseshoe” Through Time Showing Sampling Attempts that did not Capture Redside Dace

Figure 3: Distribution of redside dace in the “Golden Horseshoe” through time showing sampling attempts that did not capture redside dace.

Based on Holm and Andersen (2005).

Figure 4: Distribution of Redside Dace in Southwestern Ontario Through Time, Showing Sampling Attempts that did not Capture Redside Dace

Figure 4: Distribution of redside dace in southwestern Ontario through time, showing sampling attempts that did not capture redside dace.

Based on Holm and Andersen (2005).


Table 1: Trends in Occupied Range for Canadian Redside Dace Populations
Drainage and streamTrend in range IncreaseTrend in range StableTrend in range DeclineTrend in range ExtirpatedComments
Lake Ontario     
Pringle Creek  XX?May be extirpated
Lynde Creek  X Small range reduction
Carruthers Creek X?   
  Duffins Creek  XX?May be extirpated from two tributaries and main stem
Petticoat Creek  XX?Probably extirpated (not collected since 1954)
Highland Creek   XLast seen in 1952
Rouge River  X Remains widespread in watershed, small range reduction
Don River  X Large range contraction
Humber RiverXXX Range expansion in West Humber, stable in east Humber, contraction in main stem
Mimico Creek   XLast seen in 1949
Etobicoke Creek   XLast seen in 1949
Clarkson Creek   XLast seen in 1927
Credit River  XXExtirpated from Levi’s creek, range reduction in Silver Creek.
Morrison Creek  XX?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
Lake Simcoe     
Holland River  X Large range reduction
Lake Erie     
Irvine Creek  X Large range reduction
Lake Huron     
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.


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