Carmine shiner (Notropis percobromus) recovery strategy: chapter 3

1. Introduction

In 2001, the carmine shiner, Notropis percobromus (Cope, 1871), was designated as a “Threatened” species by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) (COSEWIC 2001), and was listed as such under Schedule I of the Species at Risk Act (SARA) on 5 June 2003. Its status was re-examined and confirmed by COSEWIC in 2006, based on an update status report (COSEWIC 2006).  

This recovery strategy was developed by the Carmine Shiner Recovery Team, which was formed in 2003. The team includes representatives from Fisheries and Oceans Canada, Manitoba Department of Water Stewardship, Environment Canada, scientists currently studying carmine shiners, and other potentially affected stakeholders (see Acknowledgments).

This document presents the recovery strategy for the carmine shiner in Canada in fulfillment of the SARA requirements. It proposes a maintenance and protection approach for the species and its habitat, and follows the two-step model developed by the National Recovery Working Group (2004).  Development of the recovery strategy is the first step, followed by the development of an action plan to implement its recommendations.

2. Background

The carmine shiner (N. percobromus) population in Manitoba was previously identified as the rosyface shiner (N. rubellus) (Houston, 1994, 1996; COSEWIC 2001), and was assessed as such by COSEWIC in its 2001 status assessment.  Subsequent reviews of the N. rubellus species complex suggests that these fish are in fact carmine shiners(Wood et al. 2002; Stewart and Watkinson 2004; Nelson et al. 2004). Despite the name change, the reason for their “Threatened” status, namely that the Manitoba population is small and disjunct within a restricted Canadian distribution, still applies.  Based on an update status report, COSEWIC reaffirmed its assessment of “Threatened” for the Manitoba populations of the carmine shiner in 2006.  Information obtained from that update status report and new information obtained by the recovery team is summarized below.

2.1 Species Assessment Information from COSEWIC

Assessment Summary -- April 2006

Common name: Carmine shiner

Scientific name: Notropis percobromus

Status: Threatened

Reason for Designation: This freshwater fish species occurs in an extremely restricted area of Manitoba. The major threat to the species is the alteration in water flow as a result of stream regulation.

Occurrence Manitoba.

Status History: Designated Special Concern in April 1994. Status re-examined and designated Threatened in November 2001 and in April 2006. Last assessment based on an update status report.

2.2 Description

2.2.1 Taxonomy

The carmine shiner is a small minnow of the genus Notropis, the second largest genus of freshwater fishes in North America. Many species in this genus are difficult to distinguish from one another and phylogenetic relationships¹ among them are largely unresolved (Dowling and Brown 1989). Recent allozyme² studies support the existence of at least five species that had hitherto been recognized only as “rosyface shiners”, including the rosyface shiner, highland shiner (N. micropteryx), rocky shiner (N. suttkusi), carmine shiner, and a species that has not yet been described (Figure 1) (Wood et al. 2002). Stewart and Watkinson (2004) accepted the carmine shiner as the identity of the Manitoba population(s) on the basis of the biogeographic information in Wood et al. (2002) and in conformity with Nelson et al. (2004). COSEWIC has also officially adopted the name of carmine shiner to describe the Manitoba populations. Consequently, all future reference in this report will be to the carmine shiner.  Ongoing studies by Dr. Chris Wilson of the Ontario Ministry of Natural Resources (pers. comm. 2005) have confirmed that the carmine and rosyface shiners are separate taxa, as is emerald shiner (N. atherinoides), based on both mitochondrial (ATPase 6 and 8 genes) and nuclear (rRNA ITS-1) DNA sequences.  These studies show that the fish in Manitoba are carmine shiners, like those to the south, and not rosyface shiners like those in eastern Canada.  Consequently, all future reference in this report will be to the carmine shiner.

Hypothesized geographical distribution of species

Figure 1. Hypothesized geographical distributions of species in the Notropis rubellus species complex based on geographical variation of allozyme products (modified from Wood et al. 2002).

The existence of various distinct forms within N. percobromus supported by morphological characters and phylogenetic analyses of allozyme data may eventually warrant taxonomic recognition (Wood et al. 2002).  Since populations in the Whitemouth and Winnipeg rivers are apparently disjunct from those in the Red River and elsewhere, and were likely isolated there by deglaciation, they may be affected by any future taxonomic revisions.

2.2.2 Identifying features

Carmine shiners are slender, elongate minnows that can be distinguished from other minnows in Manitoba by the following features: 1) the origin of the dorsal fin is located behind a line drawn vertically from the insertion of the pelvic fins, 2) absence of a fleshy keel on the abdomen and of a strongly decurved lateral line, 3) a narrowly conical snout that is equal in length, or nearly so, to their eye diameter, 4) 5-7 short gill rakers on the lower limb of the first gill arch, the longest being about as long as the width of its base, and 5) 4 slender, hooked, main row pharyngeal teeth (Stewart and Watkinson 2004; K.W. Stewart, Univ. of Manitoba, Winnipeg, pers. comm. 2005) (Figure 2). The last three characters distinguish the carmine shiner from the emerald shiner, with which it is often confused. The emerald shiner has a more blunt, rounded snout, usually only about 3/4 the length of the eye diameter; 8-12 gill rakers on the lower limb of the first arch, the length of longest being twice the width of its base; and four stouter, and only slightly hooked, pharyngeal teeth in the main row on each side (K.W. Stewart, pers. comm. 2005).

Carmine Shiner

Figure 2. Carmine shiner, Notropis percobromus (Photo courtesy of D. Watkinson, DFO, Winnipeg.)

Outside of the breeding season carmine shiners are olive green dorsally, silvery on the sides and silvery white on the belly (Scott and Crossman 1973). They have black pigment outlining the scale pockets dorsally, and freshly caught adult specimens often retain pinkish or rosy pigment on the opercula and cheek, which becomes more vivid and extensive during spawning. Fins are transparent. Breeding males develop fine, sandpaper-like nuptial tubercles on the head, on some predorsal scales, and on the upper surface of the pectoral fin rays.

The spawning colours of the carmine shiner in Manitoba are quite vivid (Lowdon et al. in review).  Spawners turn a bright orange-red colour around their cheeks and at the base of each fin.  In some fish the entire head turns this colour.  In male rosyface shiners the entire head turns an orange-red colour, at least to the nape, and the belly a lighter red (Scott and Crossman 1973). Breeding females are usually a paler colour. Pigmentation on the sides is usually bordered below by the lateral line. Adult carmine shiners in the Whitemouth River grow to at least 67 mm in fork length (Lowdon et al. in review).

2.3 Population and Distribution

2.3.1 Distribution

Within Canada, the carmine shiner only occurs in Manitoba where it is at the northwestern limit of its range (Figure 3). The species’ presence in the Winnipeg River upstream of waterfalls that were insurmountable barriers to movement (now sites of hydroelectric dams) and its apparent absence from the lower Red River and Lake

Distribution of Carmine Shiner

Figure 3. Distribution of the carmine shiner in Canada based on sampling of the Whitemouth and Winnipeg river watersheds within Manitoba and northwestern Ontario in 2002 to 2006 (Courtesy of D. Watkinson).

Winnipeg, suggest that colonization may have been via a post-glacial connection with the headwaters of the Red Lake River in Minnesota. This dispersal track is shared with the hornyhead chub (Nocomis biguttatus) and the fluted shell mussel (Lasmigona costata) (K.W. Stewart, pers. comm. 2004; Clarke 1981).  Alternatively the carmine shiner may have colonized via the Rainy River watershed from Upper Mississippi headwaters in northwest Minnesota, a dispersal track shared by a number of other fish species in southern Manitoba.

Houston (1996) reported the distribution of the carmine shiner only from the Whitemouth River and its tributary the Birch River (J.J. Keleher ROM 17539; Smart 1979; Houston 1996). More recent sampling has extended that range with additional specimens collected from the Whitemouth River, from its tributaries the Birch and Little Birch rivers, and from the Winnipeg River immediately below Whitemouth Falls (Clarke 1998; Stewart and Watkinson 2004; Lowdon et al. in review). Specimens were also collected from the Winnipeg River in the Pinawa Channel immediately below the Old Pinawa Dam, from the Bird River at the first set of rapids upstream from Lac du Bonnet (Winnipeg River mainstem lake) and at the mouth of Peterson Creek, a Bird River tributary. All of these new reports are from reaches of the Winnipeg River system downstream of the Whitemouth River outlet. Stewart and Watkinson (2004) previously reported carmine shiners from Forbes Creek, a tributary of George Lake, and from Tie Creek, the outlet to George Lake, which discharges into the Winnipeg River upstream from the confluence of the Whitemouth and Winnipeg rivers, but on re-examination these fish proved to be emerald shiners (K.W. Stewart, pers. comm. 2005). An historical report of carmine shiners further upstream on the Winnipeg River system, in Lake of the Woods (Evermann and Goldsborough 1907), has not been verified. 

Outside of Manitoba, the nearest known populations of carmine shiner are found in the Lost River tributary of the Red Lake River watershed (Red River drainage) in northwestern Minnesota (Figure 4). Specimens from that river system were obtained in 2004 for morphometric study and DNA analysis (Konrad Schmidt, MinnesotaDepartment of Natural Resources, St. Paul, MN).

2.3.2 Population Size and Trends

Prior to its listing by COSEWIC, the carmine shiner had only been reported incidentally (e.g., Smart 1979). Since then, directed samplings have extended its known range (Stewart and Watkinson 2004). The species is common but not abundant in the midcourse reach of the Whitemouth River (Smart 1979). The lack of information on its distribution and abundance may be an artifact of limited sampling, and of past confusion with the emerald shiner.

Rapids and falls, now largely replaced by hydroelectric dams, have partitioned fish habitat in the Winnipeg River mainstem.  Falls at the mouth of the Whitemouth River are a barrier to its re-colonization from the Winnipeg River. These barriers significantly reduce any natural rescue potential for the species. In addition, the original dispersal route, presumed to be from the Red Lakes area of Minnesota, may no longer be available. The percentage of the global range of the carmine shiner in Canada remains uncertain pending additional sampling in the Winnipeg River and Lake Winnipeg watersheds and genetic studies to clarify the relationship between these fish and other members of the Notropis rubellus species complex.

Location of Carmine Shiner Population

Figure 4. Locations of carmine shiner populations in Manitobain relation to those in the Red Lake River of Minnesota, where the nearest known other populations of the species occur.

2.3.3 Nationally Significant Populations

The carmine shiner has no direct economic importance and limited importance as a forage species, but is of significant scientific interest (Scott and Crossman 1973; Houston 1996; Stewart and Watkinson 2004). It does have intrinsic value as a contributor to Canada’s biodiversity and as a potential colonizing species. Being at the periphery of the species range, populations in Manitoba may be unique and provide evidence of local adaptation to their habitat and genetic differentiation from other populations of the species (Stewart and Watkinson 2004). This may constitute a significant component of the genetic diversity of the species. Scientific studies of these populations might improve our understanding of the timing and routes of post-glacial re-colonization of Manitoba by fishes (Houston 1996). They may also provide evidence of genetic adaptation near the limit of a species’ distribution.

2.4 Species’ Needs

2.4.1 Biology and Life History

Information on the carmine shiner is limited and somewhat confused because many studies of the rosyface shiner species complex were conducted on eastern populations before the western populations were recognised as a distinct species (i.e., carmine shiner). The COSEWIC review by Houston (1996) included information on both species, as did Becker (1983). To avoid this problem, surrogate information from the closely related rosyface shiner is presented only where there is no specific information for the carmine shiner.

Growth

Carmine shiners in Manitoba live to at least age 2 with spawning individuals (male and female) attaining fork lengths in the range of 55 to 67 mm (Lowdon et al. in review).  In New York State, some rosyface shiners live to age 3, with fewer males than females attaining that age (Pfeiffer 1955).

Reproduction

In Manitoba, carmine shiners in spawning condition have been caught below the Old Pinawa Dam, in the mainstem of the Whitemouth River, and in the Birch River near its confluence with the Whitemouth River (Lowdon et al. in review).  Ripe and running fish were caught between 13 June and 26 July at water temperatures of 19.3 to 22.5°C, in areas with water velocities up to 0.53 m/s, depths of 0.2 to 1.4 m, conductivities of 102.6 to 242 μS/cm and Secchi disk readings of >0.6 to at least 1.4 m.  Substrates in these areas ranged from sand, to cobble and boulder, and bedrock. 

Little is known of the species’ spawning habits in Canada although they are probably similar to those of the rosyface shiner. Spawning of carmine shiners in the southern part of their range and of rosyface shiners in Great Lakes watersheds typically occurs in riffles in May and June at temperatures of 20 to 28.9ºC (Starrett 1951; Pfeiffer 1955; Reed 1957a; Miller 1964; Pflieger 1975; Baldwin 1983; Becker 1983). Cold spring weather will delay the spawning of rosyface shiners (Reed 1957a), and in the Des Moines River, Iowa, populations of early spawning species--including carmine shiners may be limited by normal high river stages in May and June (Starrett 1951). Further south, in Missouri, carmine shiners spawn from mid-April to early July, with the peak of activity in May and early June (Pflieger 1975). However, these observations of more southerly populations may not be directly applicable to Manitoba populations.  The spawning frequency of northern populations of carmine shiner is currently unknown.

During spawning, schools of rosyface shiners break up into groups of 8 to 20 fish that spawn over depressions in the gravel (Pfeiffer 1955; Miller 1964). Often, these depressions are nests constructed by other cyprinids, such as the hornyhead chub and creek chub (Semotilus atromaculatus) (Miller 1964; Vives 1989), some are also occupied by the common shiner (Luxilus cornutus) (Reed 1957a; Miller 1964; Baldwin 1983; Vives 1989). Spawning by rosyface shiner was described by Pfeiffer (1955) and Miller (1964). Hermaphroditism has been found among rosyface shiners in Pennsylvania (Reed 1954), and may also occur among carmine shiners in Manitoba (K.W. Stewart, pers. comm. 2005).

The fecundity of carmine shiners (n = 20 females) sampled in Manitoba ranged from 694 to 2,806 eggs per female (Lowdon et al. in review). This is higher than for rosyface shiners collected in New York (Pfeiffer 1955).  Both species mature at about age 1, and the number of eggs per female increases with size and age (Pfeiffer 1955; Lowdon et al. in review).  Unfertilized eggs are spherical and dull grey (Reed 1958). They are 1.2 mm in diameter within the female and expand to 1.5 mm on contact with water. Fertilized eggs turn bright yellow and become water-hardened and adhesive. At 21.1ºC (70ºF) they hatch in 57 to 59 hours. Newly hatched larvae take cover in the interstices of bottom gravel (Pfeiffer 1955), presumably until egg yolk absorption is complete.

Hybridization of the carmine shiner with other species has not been described but is likely given that the rosyface shiner hybridizes naturally with several species including common shiner (Raney 1940; Pfeiffer 1955; Miller 1964), mimic shiner (Notropis volucellus) (Bailey and Gilbert 1960), and striped shiner (Luxilus chrysocephalus) (Thoma and Rankin 1988).

Ecological Role

Carmine shiners in Canada eat a variety of invertebrates during the summer, mostly aquatic and terrestrial insects especially dipterans (Lowdon et al. in review).  They are probably omnivorous, lower to mid-level consumers like southern populations of the species in the Ozarks (Hoover 1989) and the rosyface shiner in New York (Pfeiffer 1955; Reed 1957b). Aquatic insects, particularly caddisfly larvae, constituted the bulk of the diet of these fishes, but they also consumed terrestrial insects, fish eggs, algae, diatoms, and inorganic material. The young-of-the-year preferred algae and diatoms to insects. Competition for prey among minnow species in an Ozark stream led to greater dietary specialization by carmine shiners on midges (Chironomidae) (Hoover 1989). The breadth of their diet decreased in the presence of smallmouth bass (Micropterus dolomieui) and increased at higher light levels, which indicates that prey are located by sight.

Little is known of the predators, parasites, and diseases of the carmine shiner. They are likely preyed upon mostly by larger fishes and fish-eating birds. Their eggs may be eaten by darters, suckers, common carp (Cyprinus carpio), and minnows--similar to the rosyface shiner (Reed 1957a; Baldwin 1983).

2.4.2 Habitat

The habitat requirements and life history of carmine shiner are not well known, as most work on the species complex has been conducted outside the range of the carmine shiner in areas inhabited by the rosyface shiner (Pfeiffer 1955; Reed 1957a, 1957b).

In Manitoba, during the summer, carmine shiners are typically found at midwater depths of clear, brown-coloured, fast-flowing creeks and small rivers with clean gravel or rubble substrates (Smart 1979; Lowdon et al. in review).  The fish are typically in or near riffles and behind the cover of boulders or fallen trees. They are not known to migrate but may move into deeper pools and eddies in winter, and are sometimes present in lakes near stream mouths. The species’ apparent absence from the lower Red River, between Grand Forks and Lake Winnipeg, suggests that turbidity and fine sediment substrates may limit dispersal. These minnows may be intolerant of sustained turbidity (Trautman 1957; Becker 1983), but can tolerate pulses of turbidity in the Whitemouth River watershed associated with natural flood events (Stewart and Watkinson 2004).

Smart (1979) captured carmine shiners at 15 of 18 midcourse sites sampled on the Whitemouth River, and at 2 of 12 sites sampled on the lower 19 km of the Birch River. The channel of the midcourse reach of the Whitemouth River is gently winding and ranges in width from 18 to 36 m with sand, pebble, and cobble bottom substrates and numerous riffles. The channel of the lower Birch River is similar but relatively straight. Carmine shiners were not caught in the headwaters, lower course, or other tributaries of the Whitemouth River where the bottom substrate was silt and there were fewer riffles. However, more recent sampling has found them in the lower reaches of the Whitemouth River (Lowdon et al. in review).  Sampling in the Birch and Whitemouth rivers 2005 and 2006 collected them at depths of 0.12 to 2.8 m (average 0.87 m), velocities of 0.04 to 1.7 m/s (average 0.33 m/s), conductivities of 102.6 to 265 μS/cm, and water temperatures of 15.1 to 21.8°C.  They were collected over primary bottom substrates ranging from sand, gravel, and cobble to bedrock. Similar habitats are available in the Pinawa Channel at riffles above the Old Pinawa Dam.

During periods of heavy runoff, rosyface shiners in Ontario will retreat to the slower-flowing edges of flooded rivers and onto the floodplain (Baldwin 1983). While it has not been observed, carmine shiners in Manitoba may show similar behavior. Where they are available, flooded habitats may offer additional food resources and better feeding opportunities during periods of high turbidity, although this may also lead to stranding mortality. Steeply sloped, often near-vertical banks limit the availability of floodplain habitat along the Whitemouth River. Wintering habitats are not well known for either the rosyface or carmine shiners. In Ontario, rosyface shiners occupy deeper pools during the winter, where they are believed to remain inactive (Baldwin 1983).

In Manitoba, young-of-the-year carmine shiners have been caught in the Whitemouth River, about 3 km upstream from its mouth, and at the Seven Sisters Generating Station on the Winnipeg River (Lowdon et al. in review).  The water depth at these locations averaged 0.74 m, water velocity averaged 0.11 m/s, and the substrate was dominated by sand.  Baldwin (1983) caught young-of-the-year rosyface shiners in pool habitats that were relatively turbid in summer and clearer in the autumn. These fish were concentrated in areas with less than 5% plant cover of the bottom substrates, and partially forested shores.

The restricted distribution of carmine shiners in Manitoba, and the warm-water adaptation of all species of the N. rubellus complex, suggests that the carmine shiner is a relatively recent colonizer (Houston 1996) that reached the Hudson Bay Drainage from the Upper Mississippi watershed after glacial recession. Dispersal into the headwaters of the Red River in northwestern Minnesota is demonstrated by the occurrence of the species there (Koel 1997). They may also have reached Rainy River headwaters adjacent to the Upper Mississippi watershed, as there is an early report of the species from Lake of the Woods (Evermann and Goldsborough 1907). Unfortunately, the specimens no longer exist so this identification cannot be confirmed or refuted (D. Watkinson, pers. comm. 2006).

Although the effects of climate change are uncertain, a warming trend could increase the availability of suitable habitats north of the species’ present limits.  This could include some of the tributaries located along the east side of Lake Winnipeg. Whether the species already occurs there, or would be able to colonize these areas is unknown.

Habitat Trends and Limitations

Without specific information on the habitat requirements of the carmine shiner and on the importance of different habitats for its survival, protection of the entire ecosystem may be the best means of ensuring survival of the species. This may best be achieved through broad-based ecosystem initiatives and the exercise of specific regulatory actions targeting habitats in the Whitemouth and Winnipeg rivers. Elements of these approaches are already in effect to varying degrees (see Section 5.4.2 item M3).

Habitat Protection

The Species at Risk Act (Ss.58.1) prohibits the destruction of any part of critical habitat identified for any listed endangered, threatened or extirpated wildlife species. As stated above, critical habitat for the carmine shiner cannot be determined at this time, so specific legal protection for critical habitat cannot be afforded through SARA at this time. The Manitoba Endangered Species Act protects the habitat of species that are listed by Manitoba, but carmine shiner has not yet been listed.

Other existing federal and provincial statutes and policies may provide protection to fish habitat in general. The federal Fisheries Act (R.S. 1985, c. F-14) prohibits the harmful alteration, disruption or destruction fish habitat (S.35) except as authorized by the minister and similarly prohibits the deposit of deleterious substances into waters frequented by fish (i.e., fish habitat) (Ss.36.3). The Canadian Environmental Assessment Act (CEAA) ensures that all federal regulatory actions including authorizing the destruction of fish habitat are vetted through an appropriate environmental review with consideration of species at risk. Provincially, a 130 ha headwater section of the Whitemouth River that was designated as Ecological Reserve in 1986 to protect river-bottom forest may also provide some incidental protection for carmine shiner habitat by providing upstream riparian protection (Hamel 2003).

2.4.3 Limiting Factors

Too little is known of the carmine shiner’s physiology or ability to adapt to different conditions to identify factors that might limit its recovery. The species appears to occupy a relatively narrow ecological niche, which suggests limited adaptive ability. The closely related rosyface shiner also has a narrow range of habitat requirements and responds quickly to any changes in habitat and water quality (Smith 1979; Trautman 1981; Humphries and Cashner 1994; Houston 1996). If the carmine shiner’s responses are similar, it may show long-term avoidance of pollutants (Cherry et al. 1977) and avoid water temperatures that exceed 27.2ºC (Stauffer et al. 1975). Rosyface shiners in southwest Virginia avoided chlorine in water and did not acclimate to continued exposure (Cherry et al. 1977). Their response threshold varied with water temperature and pH and was correlated with the hypochlorous fraction of the residual chlorine. Some other factors that may be important include:  the availability of key prey species; predation by other species; competition with other minnows for preferred habitat; diseases and parasites; and hybridization with other shiner species.

¹Phylogenetic relationshipsdescribe the racial history of species relative to one another.

²Allozymes are forms of an enzyme that differ in their chemistry.

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