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

Population Sizes and Trends

Population sizes have never been determined, but are probably much greater in parts of the United States than in Canada. For example, Greeley (1938) analyzed 701 collections in New York and found the redside dace at 27.1% of the sites in the Allegheny watershed and 13.8% of the sites in the Chemung (Susquehanna) watershed. About 50 years later, there had been little change in the distribution of redside dace in New York. Surveys in the Allegheny River found the redside dace at 47 (27%) of 174 sites. A small decline had occurred in only one creek (Daniels, pers. comm. 2005).


Search Effort

No targeted surveys were conducted for redside dace in Canada prior to 1979, whereas several recent surveys have targeted areas where redside dace are known from historical records or where suitable habitats existed. Many historical records of redside dace result from the extensive surveys by the Ontario Department of Planning and Development (ODPD) from 1946 to 1959 in several watersheds of southern Ontario. These and other surveys prior to 1970 were conducted with seine nets and traps. In the 1970s, the Ontario Ministry of Natural Resources (OMNR) conducted stream surveys which included systematic fish sampling using a variety of gear types (including backpack electrofishing) throughout most streams, rivers and their major tributaries in southern Ontario. In 1979, specific survey efforts were directed to sampling redside dace and 12 other species thought to be at risk for inclusion in a COSEWIC list of rare, threatened, endangered and extinct fishes of Canada (McKee and Parker 1982). The Royal Ontario Museum (ROM) sampled 69 sites in 1985 (38 sites with historical redside dace records) specifically searching for redside dace. For the last 8 years, numerous surveys have been conducted by the ROM, Conservation Authorities, Fisheries and Oceans Canada (DFO), OMNR and Ontario Streams throughout the range of redside dace in Ontario to confirm its distribution and investigate abundance at some sites. In addition to these specific search efforts, records of redside dace have been contributed by consultants, management agencies and students conducting work for other purposes. These have been documented in a database (Holm and Andersen 2005) and are summarized in Tables 1-22 of the Appendix. It is important to note that most of the recent records for redside dace are related to specific search efforts for this species, while most of the early records come from general survey work.

A repeat sampling event may suffer from a number of problems including unintentional sampling at the wrong location or in unsuitable habitat, differences in methods or effort, changed environmental conditions (e.g., water levels, current speed, temperature, timing, turbidity), misidentification of the species, and a shift in habitat location as the stream course moves naturally over time or has been intentionally altered. Therefore, some differences in results between the original sampling event and the repeat sampling event may result from factors other than a change in the status of the redside dace in the stream. 


Abundance

The total Canadian population size is unknown and would be very difficult to estimate accurately. Based on the number of successful collecting events and the total number of individuals collected, the healthiest populations occur or occurred in the Humber, Rouge, Don, Credit and Saugeen watersheds. Despite such healthy populations, the redside dace is still described as a rare species in these watersheds (Parker et al. 1988).


Fluctuations and Trends

Sampling has been adequate in most watersheds to qualitatively identify trends in abundance. This sampling indicates that declines or extirpations have occurred in 21 of 24 Canadian watersheds (see Table 1, Appendix: Tables 1-22). Abundance has probably remained relatively stable in three streams (Carruthers Creek, Gully Creek, and Two Tree River), and within the East Humber River of the Humber River watershed. There is evidence that a range expansion may have occurred in the West Humber River portion of this watershed. While range reduction and, presumably, declines in abundance have occurred in Sixteen Mile Creek, the main stem of the Humber River, the Rouge River and Fourteen Mile Creek, there are still fairly abundant populations remaining in large parts of these streams. The species has probably been extirpated from five streams (Highland, Mimico, Etobicoke and Clarkson creeks and a Niagara area stream). Redside dace may also be extirpated from all or parts of five additional streams (Petticoat, Pringle and Morrison creeks and parts of Duffins Creek and the Credit River). Large declines, or extirpations, have occurred in six creeks (Morrison, Bronte, Spencer, Irvine, Meux and Kettleby) that were presumed to have healthy or stable populations in 1985 (Holm and Crossman 1986 and Parker et al. 1988).

Lake Ontario Drainage

Pringle Creek: The redside dace has not been seen since 1959, despite efforts in 1985 (Holm and Crossman 1986) and 1999 (Andersen 2002) (Appendix: Table 1). Andersen (2002) concluded that the species is severely limited or extirpated from Pringle Creek.

Lynde Creek: The redside dace was first captured at 5 sites in the upper half of both branches of Lynde Creek in 1959 (Appendix Table 2a). In 1983 it was reported from 10 new sites in the east branch but visits to two ODPD sites in 1985 failed to catch the species. Sampling conducted between 1999 and 2001 (Andersen 2002, Andersen unpublished data) found them at only 1 of the 5 ODPD sites (Appendix Table 2a) but captured them at another 10 new sites in both branches (Appendix Table 2b). Results of these surveys suggest range contraction in the east branch, and the maintenance of range in the west branch. Two 1959 records in lower Lynde Creek (2.4 km NW of Whitby, listed by Crossman and Holm (1986), appear to be erroneous (see ROM Accession 525). One of them was sampled in 2000 and failed to yield redside dace (Anderson pers. comm. 2001).

Carruthers Creek: This is a local name for a small tributary of Lake Ontario just west of Ajax. The redside dace was first recorded from the lower reaches of this creek in 1978 (Natural Heritage Information Centre, Element Occurrence). Sampling in 2001 at two sites, located about 10 km farther upstream, resulted in the capture of 90 redside dace (Ruthven, pers. comm. 2000).Its presence at the 1978 site has not been confirmed since, although sampling effort is unknown.

Petticoat Creek: The redside dace has not been captured in Petticoat Creek since 1954, when it was recorded at two sites by the ODPD. Attempts in 1975, 2003, and 2005 at one of the sites and several attempts at other sites yielded no redside dace. Recently, many summer survey efforts have failed to find water, except in the lower reaches of Petticoat Creek (Lawrie, pers. comm. 2005). The lack of redside dace in this sampling, and the lack of reports of redside dace in a 50-year period, suggests that the species may be extirpated in Petticoat Creek.

Duffins Creek: Known from five tributaries and the main branch, the redside dace has only recently been found in three (Michell Creek in 2003, a Brougham Creek tributary in 1999, and Ganatsekiagon Creek in 1996). Despite continuing to be found at new sites, sampling conducted from 1979-2003 indicates a decline in frequency of occurrence at historical sites, as well as overall numbers of individuals captured (Appendix Table 3a, b). Significant decline or extirpation has occurred in Reesor Creek, Urfe Creek and the main channel of Duffins Creek.

Highland Creek: The redside dace was last seen in the lower reaches of Highland Creek in 1952 (ROM 15637). The species has not been captured since, despite at least 4 attempts (Appendix: Table 4), and it is likely extirpated from Highland Creek.

Rouge River: The redside dace is still widespread and has been recently captured in high numbers in the tributaries of the upper Rouge River. Results of sampling at 30 historical sites, however, have seen a steady decline in the number of sites with redside dace. Although numbers captured have been relatively high, there has also been considerable effort spent to get them (Appendix: Table 5a). The species continues to be found at new sites in the Rouge in fairly high numbers but search effort is unknown (Appendix: Table 5b). Although the redside dace was still present in 2003 in Morningside Creek, sampling in 1997 and 2003 yielded 4 times fewer individuals of redside dace, and a dramatic decline in relative abundance (4.5% in 1984 and 1985 vs. 0.1% in 1997 and 2003).

Don River: The redside dace has demonstrated a dramatic range contraction in both branches of the Don River, and may be near extirpation in the Don River West Branch. It was first captured in the lower East Branch in 1926 and again in 1935. In 1949, it was still widespread in the upper half of both sections, when the ODPD found them at 23 sites (Fig. 6). Although it appears to be maintaining itself in the upper East Don, considerable effort has yielded fewer individuals (Appendix: Table 6a) and they have been reported from very few new sites (Appendix: Table 6b). A larger decline in both number of sites and individuals captured has occurred in the West Don (Appendix: Table 7a, b). This population was still extant in 1998, but survey efforts in 2002-2003 suggest that the species may have disappeared.


Figure 6: Sampling in the Don Riverin 1949 Showing Presence of Redside Dace (solid circles)

Figure 6: Sampling in the Don Riverin 1949 showing presence of redside dace.

Open circles indicate its absence (area ~ 33 km X 37 km).


Figure 7: Summary of Results of Sampling Effort in the Don River (both branches)

Figure 7: Summary of results of sampling effort in the Don River (both branches).

Solid circles represent presence of redside dace in 1995-2004 (Dates of capture (format YYYYMMDD) in boxed labels). Open circles represent sites of past redside dace occurrence where more recent sampling for redside dace was unsuccessful (Dates of sampling in unboxed labels). Note that 3 unsuccessful sampling events in the West Branch occurred in 2002-2003 at the site that is marked with a solid circle (area ~ 32 km2).

Humber River: In 1946, a basin-wide survey was conducted by the ODPD. The redside dace was captured only in the East Humber River at 8 sites and at one site in Black Creek (TRCA 2000). After 1946, surveys suggest that the redside dace expanded its range into the main and west Humber branches. It was first found in the main branch near Bolton in 1959. Surveys in the 1970s reported the species from several more sites in the main Humber, and at two sites in the West Humber. In the 1980s, it was more widespread in the West Humber (Fig. 8). In the 1990s, it was found at a new site in the headwaters of the main Humber, but attempts in the rest of the main branch failed to catch any. Search efforts in the East Humber River at the 8 ODPD sites continue to yield redside dace, although at reduced numbers after 1994 (Appendix: Table 8a). In 1991, a juvenile was captured in Black Creek, near its mouth (ROM 62630). This juvenile indicates that between 1946 and 1991, the redside dace in Black Creek may have been present in low numbers, or it may have drifted downstream from the more healthy population in the East Humber. It continues to be found in high numbers at new sites in the Humber River as recently as 2003 (Appendix: Table 8b).

Mimico Creek: In 1935-1949, the redside dace occurred in the lower half of Mimico Creek where it was recorded at 4 sites. Several survey attempts since 1985 at these sites and others have failed to capture it (Appendix: Table 9), and it is presumed extirpated.

Etobicoke Creek: In the 1940s, the redside dace occurred in the lower and middle half of Etobicoke Creek and its tributaries (Appendix: Table 10a). No sampling is known from three sites in the middle reaches, which have become highly modified as a result of the expansion of Pearson Airport and adjacent development. Surveys at the two sites in lower Etobicoke Creek have failed to find it since the late 1940s despite considerable effort (Appendix: Table 10a, b), and it is presumed extirpated.

“Clarkson Creek”: No redside dace have been captured in the creeks in Clarkson since 1927. In 1985, two creeks in Clarkson were sampled at 9 sites, 7 in Sheridan Creek and 2 in Turtle Creek (Holm and Crossman 1986). Other attempts in these creeks in 1986 (ROM Accession 5021), 1994 (ROM Accession 6186), 1996 (ROM Accession 6420) and 2004 (Coker pers. comm. 2004) failed to capture redside dace.

Credit River: In the Credit River system, the redside dace is widely distributed, but rare. It has been documented from the main branch and several tributaries: Roger’s Creek, Silver Creek and three of its tributaries (Black Creek, Nichols Creek and Snows Creek), Huttonville Creek, Fletcher’s Creek and Levi’s Creek. Recent sampling attempts have discovered them ina tributary of Caledon Creek and Springbrook Creek.  The most comprehensive survey occurred in 1954 when the ODPD documented the redside dace at 12 sites. Sampling attempts from 1965 to 2003 at these sites indicate a decline in both frequency and number of individuals (Appendix: Table 11a). Repeated sampling in Levi’s Creek has yielded no redside dace, and repeated sampling in Silver Creek and its tributaries has yielded only a single specimen in 2005. Decline also appears to be occurring in most of the other creeks of the Credit River. Although a single redside dace was captured in 2003 in Fletcher’s Creek, many attempts, particularly those in the more heavily urbanized middle reaches, have yielded none. There is evidence that some of the decline has occurred very recently.Sampling since 1999 (8 attempts) conducted by Credit Valley Conservation has failed to capture redside dace in Huttonville Creek at a site where every sampling attempt before 2000 had yielded redside dace. Status of the population in the Caledon Creek tributary is unknown but the creek was dry when visited in 1999 (Grewal pers. comm.1999).


Figure 8: Distribution of Redside Dace in the Humber River Through Time

Figure 8: Distribution of redside dace in the Humber River through time.

Open circles are sampling sites for time period indicated at lower left. Closed circles indicate presence of redside dace. 1921-1938: Royal Ontario Museum; 1946: ODPD (summarized in Wainio and Hester (1972) and by Toronto Region Conservation Authority (2000); 1959: Wainio and Hester (1972); 1970-1999 Toronto Region Conservation Authority (2000) [area~ 45 km X 53 km].

Morrison Creek: In 1954, the redside dace was widespread in both branches of Morrison Creek where it was found at 6 of 7 sites sampled by the ODPD. Sampling attempts in 2000-2003 at 5 of these sites resulted in no redside dace (Appendix: Table 12a). Although two specimens were found at a new site in 2000 (Appendix: Table 12b), these were captured after electrofishing 1.7 km of stream. Two subsequent attempts in 2003, near or at that site, failed to capture any redside dace. The species is, therefore, either extirpated or near extirpation.

Sixteen Mile Creek: In 1957, the redside dace was widespread in the upper half of all three branches of Middle Sixteen Mile Creek. It was found at 9 sites in the west, 4 in the middle and 1 in the east branch (ODPD 1957). Sampling in 1995-2003 has failed to find the redside dace at the most upstream sites of all three branches, but they were found in the middle and lower reach of the west and in tributaries of the lower reach of the middle branch. Three sites in the upper reaches of Middle Sixteen Mile Creek where the redside dace was captured in 1957 and 1975 were sampled in 2001 and no redside dace were captured (Watson-Leung, pers. comm. 2001). Despite this apparent range contraction,the redside dace is still thriving in many tributaries of Sixteen Mile Creek. Sampling of historical sites has had a high rate of success recently (Appendix: Table 13a) and the species continues to be found at new sites (Appendix: Table 13b).

Fourteen Mile Creek: In 1957, redside dace were captured at 3 of 8 sites sampled by the ODPD. It occurred from near the mouth to near the headwaters. Surveys in 1985, however, found the redside dace at only 1 of 3 of these sites, and it is likely that it is no longer found near the mouth and in a small tributary entering Fourteen Mile Creek from the east. In 1998-2003 15 sampling events at 12 sites captured 288 individuals of redside dace (Appendix: Table 14a, b) indicating that a healthy population of redside dace still occurred throughout the remaining historical range of Fourteen Mile Creek.

Bronte (Twelve Mile) Creek: The redside dace was first captured in 1958 in surveys by the ODPD, but locality data of these sites are missing. Surveys conducted in the 1970s found them at five sites throughout most of Mountsberg (Badenoch) Creek and at six sites in the main branch in a 20 km stretch. At least five of the sites yielded over 10 specimens and two sites yielded 20 and 23 specimens each (Appendix: Table 15a). In 1995-2000, surveys at 7 of these sites resulted in the capture of only a single individual (Appendix: Table 15a) in the main branch. Most of these recent surveys have been in Mountsberg Creek, where the redside dace has virtually disappeared. Since 1979, the species has been captured at only one new site (Appendix: Table 15b) in the main branch.

Spencer Creek: Parker et al. (1988) suggested that the redside dace population in Spencer Creek was stable in 1985. This was based on 1970s surveys that found the species widespread in the upper half of Spencer Creek and a tributary, Flamborough Creek. Redside dace, however, appear to be now present only in very low numbers in a small stretch of the main branch of Spencer Creek. Sampling in 1993 at 11 sites within the historic range captured redside dace at four sites in a 1 km stretch of the main branch. It was not captured from three sites upstream or four sites downstream, or from a site in lower Flamborough Creek (Staton et al. 1993). Sampling in 1995 (Thompson et al. 1995) reported the redside dace from two sites in the main branch, and at a new site in Fletcher Creek, a cold-water tributary that flows into upper Spencer Creek. There is no voucher and this latter record may have been misidentified (Duncan pers. comm. 1998). Surveys in 1998, 2001 and 2004 found no redside dace at 3 sites of former occurrence (Appendix: Table 16a). Only a single individual was captured at a site close to the ones captured in 1993 after considerable fishing effort (Holm 1999).

Niagara Peninsula: The species was last observed in 1960 from a stream in the Niagara Peninsula (near the 7th Lock of the Welland Canal). This may have been Ten Mile Creek or a tributary of Twelve Mile Creek. These streams now run through St. Catharines, and it is unlikely that this population is still extant, although there has been no known sampling at the site.

Lake Simcoe Drainage

Holland River: In 1976-1980 the redside dace was recorded from three sites in a small Holland River tributary, Kettleby Creek. In 1994 it was found in another tributary, Sharon Creek at one site, and it was recorded from a third unnamed tributary of the South Holland Canal just west of Kettleby Creek at one site (Gamsby & Mannerow Limited, 1995). Extensive sampling between 1988 and 2003 in Kettleby Creek and Sharon Creek (Appendix: Tables 17 and 18) resulted in the capture of only a single redside dace at one site in Kettleby Creek. This sampling indicates that, in 2003, the range of the redside dace in the Holland River system appears to be greatly reduced from previous levels. No known attempts have been made in the unnamed tributary of the Holland Canal west of Kettleby Creek since the 1995 report.

Lake Erie Drainage

Irvine Creek: In the 1970s, the redside dace was widely distributed in Irvine Creek (ROM Accession 2701, Parker and McKee 1980). Extensive sampling at the 5 historical redside dace sites and many new sites in Irvine Creek in 1997-2005 (Holm 2003, Mandrak, pers. comm. 2005) suggests that it has disappeared from three of the sites (Appendix: Table 19a), although relatively high numbers were captured at three new sites in 2001-2003 (Appendix: Table 19b). There is recent evidence, however, that the abundance at a site where 25 individuals were captured in 2001 (Holm 2003) has now been significantly reduced. Three sampling events at that site in 2003-2005 yielded only two specimens (Barnucz, pers. comm. 2005).

Lake St. Clair Drainage

Thames River: A record exists for the Thames River from “a creek near Sebringville”, but a voucher specimen could not be found (Kott, pers. comm. 2000). Extensive sampling in streams tributary to the Thames River in the Sebringville area in 1997 by the ROM and the Upper Thames Region Conservation Authority found no redside dace. If the original record was valid, it appears unlikely that the species exists there now.

Lake Huron Drainage

Saugeen River: In 1953 and 1954, surveys by the ODPD recorded redside dace from five sites in a 13 km stretch in Meux Creek, at one site in the headwaters of the South Saugeen River, and at 20 sites in a stretch of approximately 40 km in the upper Saugeen River and its tributaries. In 1972, it was found at one additional site in the upper Saugeen River (Appendix: Table 20b) and in 2001, it was found at three additional sites in the headwaters of Meux Creek (Appendix: Table 21b). Surveys in 1985-2004 in the upper Saugeen River captured redside dace at only 3 sites in 2000 in a 2.4 km section in the headwaters of the Saugeen River (Appendix: Table 20a). Abundance of the redside dace in Meux Creek was still relatively high in 1985, when over 100 individuals were captured at 4 sites (Appendix: Table 21a). Extensive sampling in 2004, however, at all 5 ODPD sites resulted in the capture of only a single individual (Appendix: Table 21a). A 1992-1993 study by Cam Portt and Associates (Coker, pers. comm. 2001) found 15 individuals of redside dace prior to construction of a road crossing in Meux Creek, but none were captured after construction in 1993. A 1977 record of redside dace in Greenock Creek reported by Parker and McKee (1980) was considered invalid by Holm and Crossman (1986). This record is based on an observation of 2 specimens by the collector (D. Krewtzweiser) and documented on a Canadian Museum of Nature (CMN) catalog sheet (CMN1979-1205A); however, no voucher specimens exist. Sites near or at the described locality sampled in 1985 and 2004 did not yield any redside dace (Holm and Crossman 1986; Forder 2005). The failed attempts to capture redside dace in the South Saugeen, most of the upper Saugeen River and in Meux Creek indicate that its range has declined dramatically in the Saugeen River in the last 46 years. Of 26 sites, it has been recaptured at only 7 (27%) since 1954. Based on estimated occupied stream length, the range of the redside dace in the Saugeen River has declined from approximately 54 km to 3 km (6.5% of its estimated range in the early 1950s).

Gully Creek: A total of 8 redside dace were captured at two of three sites in 1980 in this small Lake Huron tributary (Appendix: Table 22). Attempts at both sites in 2001 captured six specimens at only one site. Additional sampling for rainbow trout in 1988 failed to catch any redside dace (Malhiot pers. comm. 2001).

Two Tree River: A total of 4 specimens have been captured in 2 of 4 sampling attempts indicating that the abundance of redside dace in the Two Tree River is low.


Rescue Effect

The redside dace is confined to small streams (often in headwater areas) and there is no confirmed record from the Great Lakes proper. Therefore, it is unlikely that any dispersal from even adjacent populations in Canada, much less the more healthy U.S. populations, is possible. The healthiest populations are in Ohio (SNR), Pennsylvania (S4) and New York (S3). Rescue from any of these states is improbable because it would require migration across the open expanses of the Great Lakes. While the Michigan populations are adjacent to the Detroit River, the redside dace is a declining species in the state where it is listed as endangered (Goforth 2000).