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COSEWIC Assessment and Update Status Report on the Carmine Shiner in Canada


Information on the carmine shiner is limited and somewhat confused, since many studies of the rosyface shiner species complex were conducted on eastern populations before the western populations were recognized 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 information for the carmine shiner.


The growth and age structure of carmine shiner populations in Manitoba is unknown, as is the species’ longevity. In New York State, rosyface shiners live to age 3 years with fewer males than females attaining that age (Pfeiffer 1955). Whether carmine shiners at the northern fringe of their distribution are slower to mature and longer lived than the more southerly rosyface shiners in New York State is unknown. The spawning frequency of individuals in northern populations is also unknown.

Life Cycle and Reproduction

In Manitoba, carmine shiners have only been observed in spawning condition below the Old Pinawa Dam, where a single ripe and running female was captured on 7 July 2004 in water that was 19.3°C (D. Watkinson, pers. comm. 2004). Little is known of the species’ spawning habits and reproductive potential in Canada. Their habits 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 28.9°C (Starrett 1951; Pfeiffer 1955; Reed 1957a; Miller 1964; Pflieger 1975; Baldwin 1983; Becker 1983). The presence of adult rosyface shiners in spawning colours or with ripe gonads suggests that the actual spawning period in Ontario may extend from early May through mid-July (Baldwin 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.

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), and 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 number of eggs per female in rosyface shiner increases with size and age (Pfeiffer 1955). On average, a year-old female (age of maturation) contains 600 eggs (n=10, range 450-754), a 2-year old 1090 eggs (n=10, range 675-1460), and a 3-year old 1175 eggs (n=8, range 783-1482). 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 21.1°C (70°F) they hatch in 57 to 59 hours. Newly hatched larvae take cover in the interstices of bottom gravel (Pfeiffer 1955), presumably until yolk absorption is complete. Reed (1958) described the major stages of egg development and illustrated a newly hatched larva.

Hybridization of the carmine shiner with other species of Notropis 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 (N. volucellus; Bailey and Gilbert 1960), and striped shiner (Luxilus chrysocephalus; Thoma and Rankin 1988).


Carmine shiners in Canada probably are 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 consume terrestrial insects, fish eggs, algae, diatoms, and inorganic material. The young-of-the-year prefer 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 dolomieu) and increased at higher light levels, which indicates that prey are located by sight. In the Whitemouth River, surface insects seem to be the dominant food type and carmine shiners have been observed rising to the surface, apparently to feed (K.W. Stewart, pers. comm. 2006).


Little is known of the physiology of the carmine shiner. Rosyface shiners in southwest Virginia avoid chlorine in water and do not acclimate to continued exposure (Cherry et al. 1977). Their response threshold varies with water temperature and pH and is correlated with the hypochlorous fraction of the residual chlorine. If the carmine shiner responds similarly, it may also show continued avoidance of other pollutants. Rosyface shiners in Virginia (New River) may also avoid water temperatures that exceed 27.2°C (Stauffer et al. 1975). The responses of the carmine shiner to temperature are unknown, but are presumed to similar to those of the rosyface shiner.


Carmine shiners are not known to migrate, although they likely move into deeper water to winter. In the Whitemouth River, individuals may be dispersed downstream or into nearby ponds by flash floods caused by heavy rainfall. Their natural predisposition to disperse is unknown. The species’ apparent absence from the lower Red River, between Grand Forks and Lake Winnipeg, suggests that turbidity may limit dispersal. However, this does not mean they cannot use turbid rivers for dispersal. The detailed distribution of both carmine and rosyface shiners suggests that they disperse via large lakes and rivers, but colonize and establish in tributaries to these waters, occupying them to the first impassable obstacle upstream from the mouth. One means of dispersing via normally turbid rivers would be do so in the winter when reduction in flows resulting from surface freeze-up results in clearer water flowing beneath the ice (K.W. Stewart, pers. comm. 2006).

Interspecific Interactions

Little is known of the predators, parasites, and diseases of the carmine shiner. Carmine shiners 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).

Parasites and diseases of carmine shiners in Manitoba have not been studied. Hoffman (1970:358) listed six species of trematodes and one nematode (Spiroxys sp.) that infest N. rubellus in North American waters. This short list likely reflects limited sampling effort rather than few parasite species, since many more species have been found in L. cornutus (see Hoffman 1970:356).


The species’ ability to adapt to different conditions is unknown. It appears to occupy a relatively narrow ecological niche i.e., mid-water depths of brown coloured, fast flowing streams at the foot of ripples, which suggests limited adaptive ability.