Adult longnose dace are polygynandrous (promiscuous) because both mature males and females have multiple spawning partners. Males are territorial and breed with many females who visit their habitat (Bartnik, 1970). Female longnose dace are capable of spawning 6 or more times during their breeding season and will breed with multiple males during this time (Roberts and Grossman, 2001).
Mating System: polygynandrous (promiscuous)
Some longnose dace are capable of reproducing at age 1, all are mature by age 2 (Roberts and Grossman, 2001; Brazo, Liston, and Anderson, 1978). Mature individuals, both male and female, are approximately 75 mm in total length. While spawning typically occurs only in one year, females are capable of producing 6 or more clutches per year. Total potential fecundity ranged from 1155 to 2534 eggs for females in stream dwelling populations (Roberts and Grossman, 2001) and from 870 to 9,953 eggs per female in Lake Michigan populations (Brazo et al., 1978). Longnose dace larvae hatched 3 to 4 days after fertilization occurred; with an mean length of 5.9 mm (Fuiman and Loos, 1977; Cooper, 1980). Information on mass at the time of hatching was not available. Spawning typically occurs in summer but timing is dependent on latitude and water temperature (Edwards, Li, and Schreck, 1983). Typical spawning season takes place in late June and early July (Brazo, Liston, and Anderson, 1978) but occurs as early as late May (Reed, 1959) and as late as August (McPhail and Lindsey 1970). Peak spawning typically occurs at water temperatures between 14° and 19° C (Brazo, Liston, and Anderson, 1978).
Breeding interval: Female longnose dace are capable of having 6 or more clutches per year but typically only spawn for 1 season.
Breeding season: Longnose dace reproduce between May and July.
Range number of offspring: 1155 to 2534.
Average number of offspring: 1832.
Range time to hatching: 3 to 4 days.
Range time to independence: 3 to 4 days.
Range age at sexual or reproductive maturity (female): 1 to 2 years.
Average age at sexual or reproductive maturity (female): 2 years.
Range age at sexual or reproductive maturity (male): 1 to 2 years.
Average age at sexual or reproductive maturity (male): 2 years.
Key Reproductive Features: semelparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous
In stream and lake-dwelling populations, spawning occurs over gravel. Male longnose dace construct a small nest in the pebbles where eggs are deposited (McPhail and Lindsey, 1970). Males are territorial and defend their spawning habitat, which is visited by multiple females (Brazo, Liston, and Anderson, 1978). After spawning, little or no parental care is given the eggs. They are are categorized as benthic spawners who broadcast their eggs over gravel. The eggs are not hidden (Helfman, Collette, and Facey, 1997). Embryos temporarily adhere to the gravel for 7 to 10 days and then the hatched fry become pelagic (McPhail and Lindsey, 1970; Cooper, 1980).
Parental Investment: no parental involvement; pre-fertilization (Provisioning, Protecting: Male)