Longnose dace are typically dark olive-brown with a lighter yellow-tan underbelly. A dark side stripe, present in juveniles, fades as the fish matures. This is a good distinguishing characteristic between longnose dace and their close relatives, blacknose dace, which keep their dark lateral stripe throughout their lifetime. Other identifying characteristics include a mouth on the bottom of their face with a fleshy snout projecting far beyond the mouth. A small barbel (like a whisker) is also present near the corner of the mouth. Total length is largely based on local habitat conditions; adults are usually 60 to 90 mm in length and reported maximum sizes are around 160 mm for stream dwelling fish, slightly larger for lake-dwelling longnose dace. Longnose dace have been reported to get up to 225 mm in total length. Male and female longnose dace look the same, but females are often larger than males. (Brazo, et al., 1978; Gerald, 1966; Goldstein and Simon, 1999; Page and Burr, 1991; Sigler and Miller, 1963)
Longnose dace have the widest geographic distribution of any member of the Cyprinidae family. The distribution spans much of North America, ranging from the Atlantic coast to the Pacific Ocean and from northern Mexico to the Arctic Circle in northern Canada. In the United States, longnose dace are mainly found in the northern half of the country with some isolated populations in rivers of the Appalachian Mountains and the South Pecos river in Texas, New Mexico, and Colorado. They are found in bodies of water across most of Michigan.
Longnose dace are found in fast-flowing, cold water. Most populations are found in stream riffles. When in lakes, they are typically in the fast-flowing zone less than 10 m deep, where outflow from a river mixes with lake water. Another characteristic of longnose dace habitat is rocky or gravel substrate on the lake or river bottom. Streams they inhabit tend to be small creeks and rivers with shallow pools as well as an abundance of fast-flowing riffles. Young longnose dace are found in shallow pools for the first four months following hatching. (Brazo, et al., 1978; Cooper, 1980; Edwards, et al., 1983; McPhail and Lindsey, 1970; Reed, 1959)
After fertilization, eggs develop for 3 to 4 days before hatching. These hatchling fish are very small, and have a yolk sac that is filled with nutrients that the baby fish will use until they are able to eat on their own. At this young age, they lack color and are see-through. After a few days, they begin to turn their brown color and start to develop tiny fins. By the 9th day after hatching, the sac is absorbed and the fish can eat on their own. After a few more days, they begin to develop their fleshy noses and have their adult coloration. They are considered juvenile fish at this stage.
Juvenile longnose dace continue to grow and develop in streams. Most longnose dace mature at age 2. Mature individuals, both male and female, are approximately 75 mm in total length at the time of maturation. Females typically grow larger than males by age 3. Like most fish, longnose dace continue to grow throughout their lives. (Brazo, et al., 1978; Cooper, 1980; Fuiman and Loos, 1977; Gerald, 1966; Roberts and Grossman, 2001)
Adult longnose dace have a "polygynandrous" mating system where both mature males and females have multiple spawning partners. Males are territorial and breed with many females who visit their territory. Female longnose dace are capable of spawning 6 or more times during their breeding season and will breed with multiple males during this time. (Bartnik, 1970; Roberts and Grossman, 2001)
All longnose dace are capable of reproducing at age 2. 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. Females can lay 1155 to 2534 eggs in stream dwelling populations and from 870 to 9,953 eggs per female in Lake Michigan populations. Longnose dace larvae hatch 3 to 4 days after fertilization with a mean larval length of 5.9 mm. Information on mass at the time of hatching is not available. Spawning typically occurs in summer but timing is dependent on location and water temperature. Typical spawning season takes place in late June and early July. Peak spawning typically occurs at water temperatures between 14° and 19° C. (Brazo, et al., 1978; Cooper, 1980; Edwards, et al., 1983; Fuiman and Loos, 1977; McPhail and Lindsey, 1970; Reed, 1959; Roberts and Grossman, 2001)
In stream and lake-dwelling populations, spawning occurs over gravel. Male longnose dace dig a small nest in the pebbles where eggs are deposited by females. Males are territorial and defend their spawning habitat, which is visited by multiple females. After spawning, little or no parental care is given the eggs. The eggs are not hidden. Embryos temporarily stick to the gravel for 7 to 10 days and then the hatched fry float upwards towards the surface. (Brazo, et al., 1978; Cooper, 1980; Helfman, et al., 1997; McPhail and Lindsey, 1970)
Longnose dace have a maximum reported lifespan of 5 years, but lifespan is typically only 3 years for males. Females have an expected lifespan of 4 to 5 years old. (Brazo, et al., 1978; Reed and Moultan, 1973)
While faster areas of a riffle are typically inhabited by adults, both adult and juvenile longnose dace prefer fast flowing areas in the riffles they inhabit. Juvenile longnose dace will avoid fast flowing riffles that are occupied by adults and will move to slower flowing water until the adults leave. Longnose dace are nocturnal, meaning they are most active at night. They are a sedentary species because they remain in the same general area throughout their lives and do not migrate. (Grossman, et al., 1998; Mullen and Burton, 1995; Mullen and Burton, 1998)
During the breeding season, males are territorial and stay near their spawning area; females are more mobile during this time and move throughout the stream. Exact territory size has not been determined. (Bartnik, 1970; Brazo, et al., 1978)
Detailed information on longnose dace communication and perception is not available.
Longnose dace are primarily nocturnal feeders and have well-adapted vision for night foraging. This nocturnal strategy is thought to be a combination of minimizing predation risks while still increasing efficiency in low-light conditions.
Longnose dace are well adapted for feeding on bottom dwelling insects. At night, they use benthic-rooting behavior; it is thought they locate prey by using their barbels to probe into the substrate. Their insect diet consists largely of midges, black flies, and mayflies as well as leaf hoppers, aphids, and small cicadas. Small, juvenile longnose dace feed primarily on algae until they are large enough to consume the same diets as adults. Larger adults shifted their diet toward larger insects as well as fish eggs of other species. (Beers and Culp, 1990; Brazo, et al., 1978; Gerald, 1966; Reed, 1959)
Longnose dace are potential prey species for fish-eating birds, such as herons, and predatory stream fishes including many salmon species. Their brown-ish coloration blends in well with their environment and may help them hide from predators. (Brazo, et al., 1978)
Longnose dace are wide-ranging freshwater minnows that are an important part of the food chain in many stream habitats. One of the important functions these fish provide are consuming terrestrial insects, bringing them into the aquatic food chain. Longnose dace are a potential prey species to predatory stream fishes including many salmon species. This is especially believed to occur when alewive populations crash, as salmon rely on alewives for food. Longnose dace are also hosts to several parasites. (Brazo, et al., 1978; Muzzall, et al., 1992)
There are no known negative affects of longnose dace on humans.
Longnose dace do not provide direct economic benefit to humans, but in some areas they are used as bait for fishing. (Scott and Crossman, 1998)
Longnose dace are not listed as a species of special concern, endangered, threatened, or regionally extirpated in any conservation list. They have a wide range and currently their population numbers are stable.
Kevin Duby (author), Northern Michigan University, Rachelle Sterling (editor), Special Projects, Jill Leonard (editor), Northern Michigan University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
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