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

Habitat

Habitat Requirements

The redside dace is found in pools and slow-flowing sections of relatively small headwater streams with both pool and riffle habitats and a moderate to high gradient (McKee and Parker 1982, Meade et al. 1986, Goforth 2000, Andersen 2002, Daniels pers. comm. 2005). Substrate varies from silt to boulders, but they are often associated with gravel (McKee and Parker 1982; Becker 1983; Holm and Crossman 1986, Daniels, pers. comm. 2005). Overhanging riparian vegetation in the form of grasses and shrubs as well as undercut banks and instream cover (boulders, large woody debris) are important components of redside dace habitat. Redside dace are typically found in stream segments that flow through open meadows, pasture or shrub overstory as opposed to closed canopy forest in Ontario (Andersen 2002, Parish 2004) and Wisconsin (Becker 1983). In Kentucky, redside dace are found in forested watersheds with canopy over the stream (Meade et al. 1986).

Redside dace typically occur in streams that are clear, and water clarity is often mentioned as being important to redside dace habitat (McKee and Parker 1982; Meade et al. 1986; Daniels and Wisniewski 1994; Goforth 2000). However, redside dace have been captured in Ontario in streams with moderate turbidity (Holm and Crossman 1986), and Coon (1993) suggested that redside dace may have a broader range of tolerances to temperature, turbidity and depth in areas where they are common. The redside dace is a visual feeder which probably explains its preference for clear water habitats (Daniels and Wisniewski 1994). Studies on the effect of turbidity on other fishes have shown that turbidity reduces foraging effectiveness in some species. For example, turbid water decreased growth in brook trout (Salvelinus fontinalis) because they became more active switching from drift feeding to active searching (Sweka and Hartman 2001). The volume and diversity of stomach contents in brown trout decreased progressively with increasing turbidity (Stuart-Smith et al. 2004). Bonner and Wild (2002) found that prey consumption by the Arkansas River shiner (Notropis girardi), the emerald shiner (N. atherinoides), red shiner (Cyprinella lutrensis), and sand shiner (N. stramineus) was reduced by elevated turbidity. Other species appear to be unaffected. Prey consumption by the peppered chub (Macrhybopsis teranema) and flathead chub (Platygobio gracilis) was unaffected by elevated turbidity (Bonner and Wild 2002).

Redside dace are considered to be a coolwater species (Coker et al. 2001). Becker (1983) stated that redside dace avoid warm water as well as very cold water. In Ontario, most streams where redside dace have been collected had summer temperatures less than 20 °C, although some streams were as warm as 23 °C (McKee and Parker 1982). In New York, redside dace have been collected at summer stream temperatures ranging from 13-30 °C, although most (80%) of the collections were at temperatures between 14 and 25 °C (Coon 1993). Coon (1993) suggested that the optimal summer temperature for redside dace was close to 20 °C.

Redside dace are normally found in smaller streams ranging from 1-10 m (mean= 5) in width (McKee and Parker 1982; Becker 1983), In New York, stream widths averaged 5-10 m (Daniels pers. comm. 2005). Occasional individuals have been captured in the larger main stems of Ontario rivers. It is not clear whether these individuals represent established populations, or strays from smaller tributary streams. With the exception of spawning time, redside dace reside in the deeper, slow-moving pool sections of streams. Reported stream depths for redside dace captures throughout their range vary from 0.1 – 2.0 m (McKee and Parker 1982; Becker 1983; Coon 1993, Daniels pers. comm. 2005). Coon (1993) suggested that suitable habitat for redside dace was provided by pools ranging from 11-100 cm in depth. Parish (2004) found that redside dace preferred streams with small width to depth ratios. Novinger and Coon (2000) observed that redside dace displayed a consistent preference for mid-water positions in the deepest part of pools. In New York, stream discharges at sites of redside dace capture ranged from 0.01-1.6 m3/s, with most (80%) collections occurring at discharges between 0.01 and 0.43 m3/s (Coon 1993). 

Redside dace spawn in shallow gravel riffles, usually as a nest associate of other cyprinid species (Koster 1939; Page and Johnston 1992; E. Holm, unpublished data). Parish (2004) found that Ontario streams with redside dace populations tended to have riffles with larger particle sizes than streams without redside dace, even though eggs are laid on gravel substrates.

There is no information available regarding winter habitat use, although presumably they overwinter in deep pool areas with little current. There is no information available regarding the habitat of redside dace larvae. Habitat use by juveniles has not been specifically studied, although juveniles are often collected in Ontario from the same pools as adult fish.


Habitat Trends

Loss of suitable habitat (or habitat modification) is likely the major factor contributing to redside dace declines in Ontario. Populations have been lost from several streams that have had major habitat changes associated with intensive urban development and the construction of reservoirs. Population declines associated with habitat loss have probably occurred in about one-half of Ontario’s redside dace streams, and only a few are considered to be relatively undisturbed. The species is now restricted to the relatively undisturbed headwaters of many streams where it was once widespread (McKee and Parker 1982).

As urbanization has proceeded over the last 50 years in the Greater Toronto Area, most redside dace populations have disappeared from developed areas or populations have become increasingly restricted to headwater areas (Fig. 5). Approximately one-half of the redside dace sites that have been shown to be extant over the last 15 years are within, or immediately adjacent to, areas that are scheduled to be developed over the next 16 years. The nature of stream habitat changes associated with urbanization is summarized below under Limiting Factors.


Figure 5: Distribution of Redside Dace (Clinostomus elongatus) in the Greater Toronto Area Over Time

Figure 5: Distribution of redside dace (Clinostomus elongatus) in the Greater Toronto Area over time.

Closed circles represent sites where redside dace were captured; open circles represent sites of former redside dace occurrence where sampling occurred, but no redside dace were captured; grey shading represents extent of urban area.

A draft recovery strategy has been prepared for redside dace in Ontario that is attempting to protect and restore redside dace habitats (Redside Dace Recovery Strategy 2005).


Habitat Protection/Ownership

The habitat of the redside dace receives general protection under the habitat provisions of the federal Fisheries Act. Adjacent lands receive policy level protection through the fish habitat and species at risk provisions of the Provincial Policy Statement (PPS) under the provincial Planning Act. The PPS prohibits development or site alteration on adjacent lands (within 30 m of fish habitat) unless it can be shown through an Environmental Impact Study that the fish habitat in question will not be negatively impacted. Development and site alteration is not permitted in the significant habitat of Ontario Threatened and Endangered species. Recent amendments to the Planning Act now require municipal planning decisions to be consistent with the PPS. The provincial Lakes and Rivers Improvement Act may also indirectly protect redside dace habitat when applications for the construction or maintenance of dams and dredging activities are reviewed. Alteration in or near floodplain, wetland, and/or watercourses is regulated by Conservation Authorities through the Development, Interference with Wetlands and Alterations to Shorelines and Watercourses Regulation.Aspects of the provincial Nutrient Management Act, Environmental Protection Act, Water Resources Act, Source Water Protection Act may also provide indirect protection for the habitat of redside dace.

The beds of the streams inhabited by redside dace are either privately owned or, if navigable, are generally owned by the Crown. The majority of adjacent land is privately owned and in agricultural production or in urbanizing landscapes. Lands immediately adjacent to streams in urban subdivisions are usually returned to public ownership.