Johnny darters are found throughout eastern North America, from Wyoming, Colorado, the Dakotas, and Saskatchewan east to the Atlantic seaboard as far south as North Carolina. They are also found south into Alabama and Mississippi.

Biogeographic Regions: nearctic (Introduced , Native )

Johnny darters are found throughout eastern North America, from Wyoming, Colorado, the Dakotas, and Saskatchewan east to the Atlantic seaboard as far south as North Carolina. They are also found south into Alabama and Mississippi. Populations in the Rocky Mountains of Wyoming and Colorado and the Ozark Mountains of Arkansas and Oklahoma are disjunct from other populations. They have been introduced to parts of Utah.

Biogeographic Regions: nearctic (Introduced , Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: St. Lawrence-Great Lakes, Hudson Bay, and Mississippi River basins, from Hudson Bay to southern Mississippi and from Quebec and Virginia to Saskatchewan and Colorado; Atlantic Slope in James, Roanoke, Tar, and Neuse river drainages, Virginia and North Carolina; Gulf Slope in Mobile Bay drainage, Alabama and Mississippi; recently introduced in Colorado River drainage, Colorado; common to abundant (Page and Burr 1991).

Johnny darters are small, slender fish with brown to yellow scales, paler sides, and whitish bellies. They average 51 mm in length. The backs and sides are marked with darker "saddle marks" and the sides have distinctive "W" shaped brown spots along the lateral line. There is a dark stripe that extends from the mouth to the eye, the dorsal fins are marked with brown spots, the tail fin has brown stripes, and the pectoral and anal fins are clear. Males become black on the head, upper body, and dorsal fins during the breeding season and they develop whitish knobby tips on their lower fins.

Range length: 77 (high) mm.

Average length: 51 mm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: sexes colored or patterned differently

Johnny darters are small, slender fish with brown to yellow ctenoid scales, paler sides, and whitish bellies. The backs and sides are marked with darker "saddle marks" and the sides have distinctive "W" shaped brown spots along the lateral line. There is a dark stripe that extends from the mouth to the eye, the dorsal fins are marked with brown spots, the tail fin has brown stripes, and the pectoral and anal fins are clear. The first dorsal fin has 7 to 9 spines and the second dorsal find has 11 to 14 rays. Males become dusky to black on the head, upper body, and dorsal fins during the breeding season. The ventral portion of the pectoral fins and pelvic rays develop whitish, knobby tips. The average length is 51 mm and the largest recorded individual was 77 mm.

Range length: 77 (high) mm.

Average length: 51 mm.

Other Physical Features: ectothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: sexes colored or patterned differently

Length: 6 cm

Johnny darters are found in shallow water (usually less than 0.5 m) in small to medium sized rivers, creeks, streams, and headwaters. They are found in areas with sandy, muddy, or rocky substrates, but are more common over sandy or gravel substrates in slow-moving water. They are also found along the sandy shores of lakes or large rivers.

Range depth: 64 (high) m.

Average depth: 0.5 m.

Habitat Regions: temperate ; freshwater

Aquatic Biomes: benthic ; lakes and ponds; rivers and streams

Johnny darters are found in shallow water in small to medium sized rivers, creeks, streams, and headwaters. They are found in areas with sandy, muddy, or rocky substrates, but are more common over sandy or gravel substrates in slow-moving water. They are also found along the sandy shores of lakes or large rivers. Johnny darters are generally found in benthic parts of aquatic habitats, at depths of less than 0.5 m, although they have been captured in water as deep as 64 m. Johnny darters are considered pioneer species because they can quickly move in and become established in disturbed habitats.

Range depth: 64 (high) m.

Average depth: 0.5 m.

Habitat Regions: temperate ; freshwater

Aquatic Biomes: benthic ; lakes and ponds; rivers and streams

Habitat Type: Freshwater

Comments: Most often found over sand or silt in quiet or sluggish areas of headwaters, creeks, and small to medium rivers (Leidy 1992, Page and Burr 1991), less often over gravel or in weedy areas of lakes or sandy lake shallows (Page 1983). Small to medium streams in pools over sand or bedrock (Kuehne and Barbour 1983). In Colorado, occurs most often in shallow, slow-velocity water over cobble-sand substrate (Propst and Carlson 1989). Eggs are laid on the underside of a stone or other object.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

Considerable upstream and downstream movements may precede spawning (Kuehne and Barbour 1983).

Johnny darters feed on small insect larvae and crustaceans as both adults and young. Young feed on much smaller prey, such as tiny Chironomidae larvae and Ostracoda. Adults eat Chironomidae larvae, Ephemeroptera nymphs, Trichoptera larvae, Simulium larvae, and small Crustacea.

Animal Foods: insects; aquatic crustaceans

Johnny darters feed on small insect larvae and crustaceans as both adults and young. Young feed on much smaller prey, such as tiny midge larvae and ostracods. Adults eat midge larvae, mayfly nymphs, caddisfly larvae, blackfly larvae, and small crustaceans, such as Hyalella, Cyclops, and Daphnia.

Animal Foods: insects; aquatic crustaceans

Primary Diet: carnivore (Insectivore , Eats non-insect arthropods)

Comments: Young eat mainly midge larvae and microcrustaceans. Larger individuals eat mainly midge larvae and mayfly larvae (Page 1983, Propst and Carlson 1989).

Johnny darters are important members of native aquatic ecosystems, they are important predators of small invertebrates and are prey for larger predatory fish, including game fish, and wading and diving birds.

Johnny darters are eaten by larger, predatory fish, including Salvelinus namaycush, Coregonus clupeaformis, Lota lota, Micropterus dolomieu, Perca flavescens, and others. Because of their shallow water habits, they are also likely prey of wading and diving birds, such as Ardeidae, and Nerodia. Johnny darters are cryptically colored.

Known Predators:

• lake trout (Salvelinus_namaycush)
• lake whitefish (Coregonus_clupeaformis)
• burbot (Lota_lota)
• smallmouth bass (Micropterus_dolomieu)
• yellow perch (Perca_flavescens)
• herons (Ardeidae)
• water snakes (Nerodia)

Anti-predator Adaptations: cryptic

Johnny darters are important members of native aquatic ecosystems, they are important predators of small invertebrates and are prey for larger predatory fish, including game fish, and wading and diving birds.

Johnny darters are eaten by larger, predatory fish, including lake trout, lake whitefish, burbot, smallmouth bass, yellow perch, and others. Because of their shallow water habits, they are also likely prey of wading and diving birds, such as herons, and water snakes. Johnny darters are cryptically colored.

Known Predators:

• lake trout (Salvelinus namaycush)
• lake whitefish (Coregonus huntsmani)
• burbot (Lota lota)
• smallmouth bass (Micropterus dolomieu)
• yellow perch (Perca flavescens)
• herons (Ardeidae)
• water snakes (Nerodia)

Anti-predator Adaptations: cryptic

Johnny darters use their large eyes and keen vision to find prey. They don't seem to have a good sense of small. They use touch and vision in communication during mating.

Communication Channels: visual ; tactile

Perception Channels: visual ; vibrations

Johnny darters use their large eyes and keen vision to find prey. They don't respond strongly to olfactory cues. Tactile and visual signals are used in mating communication. They have a complete lateral line.

Communication Channels: visual ; tactile

Perception Channels: visual ; vibrations

Johnny darters spawn in waters from 11.7 to 21.1 degrees Celsius, taking from 10 to 16 days to hatch. Larvae are 5 mm long at hatching and generally grow to 29 to 54 mm by September.

Johnny darters spawn in waters from 11.7 to 21.1 degrees Celsius. Temperature influences length of development to hatching, with eggs laid in April (12.8 degrees Celsius) hatching at 16 days and eggs laid in May (20 degrees Celsius) hatching at 10 days. Larvae are 5 mm long at hatching and generally grow to 29 to 54 mm by September.

Johnny darters live for up to 3 years.

Typical lifespan

Status: wild: 3 (high) years.

Johnny darters live for up to 3 years.

Typical lifespan

Status: wild: 3 (high) years.

Johnny darter males migrate to spawning areas before females and establish small nesting territories in protected, shallow waters. Males choose a stationary object, such as a log, rock, or even trash, that they will use as a nest. Males compete for nesting territories and aggressively defend their nests, even against fish up to 3 times their size. Johnny darters clean the underside of their chosen spawning object with their fins. They also enlarge the nest with movements of their body. When a female approaches, a male will begin to swim upside down under the spawning object, which attracts the female. The female swims upside down under the spawning object, alongside the male, who then prods her sides. This stimulates the female to deposit eggs, one at a time on the object, creating a small, single layer patch of eggs. Females deposit eggs in the nests of different males, and most males have several females deposit eggs in their nest.

Mating System: polygynandrous (promiscuous)

Females can have from 86 to 691 eggs, which they lay in small batches in the nests of different males. Male nests have been recorded with between 30 and 1150 eggs in them. Johnny darters can breed in their first year after hatching.

Breeding interval: Johnny darters breed once yearly.

Breeding season: Spawning occurs in the spring, usually in April or May.

Range number of offspring: 48 to 691.

Range time to hatching: 10 to 16 days.

Average age at sexual or reproductive maturity (female): 1 years.

Average age at sexual or reproductive maturity (male): 1 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous

Johnny darter eggs are attached to the underside of rocks and guarded by males until they hatch. Males rub the eggs with their fins to clean them from 13 to 16 times an hour. They also fan the eggs with their pectoral fins. When an eggs becomes covered with fungus, the male will eat it. Males aggressively defend their eggs against fish that might want to eat them.

Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Male)

Johnny darter males migrate to spawning areas before females and establish small nesting territories in protected, shallow waters. Males select a stationary object of at least 25 cm in diameter, such as a log, rock, or even trash under which spawning occurs. Males compete for nesting territories, with a side-by-side display that helps them to establish dominance. Once one is established as dominant, it drives the other male away. Male Johnny darters aggressively defend their nests, even against fish up to 3 times their size. They attack by butting the threat with their head and biting at the fins of an intruding fish. Johnny darters clean the underside of the chosen spawning object with their anal, pectoral, and tail fins. They also enlarge the nest with movements of their body. Males rarely leave their territory during the day, but territories are not defended at night. Males first swim aggressively towards females that approach their nest, but then begin to swim upside down under their spawning object, which attracts the female. The female swims upside down under the spawning object, alongside the male, who then prods her sides. This stimulates the female to move along the object and deposit eggs. Females place one egg at a time on the object, eventually creating a small, single layer patch of eggs up to 13 cm in diameter. Females mate with 4 to 6 males and males typically mate with more than 1 female.

Mating System: polygynandrous (promiscuous)

Females lay from 30 to 200 eggs at each spawning event, which they will do several times in the nests of different males. Male nests have been recorded with between 30 and 1150 eggs in them. Smaller females have been recorded with from 48 to 299 eggs and larger females with from 86 to 691 eggs. Johnny darters can breed in their first year after hatching.

Breeding interval: Johnny darters breed once yearly.

Breeding season: Spawning occurs in the spring, usually in April or May.

Range number of offspring: 48 to 691.

Range time to hatching: 10 to 16 days.

Average age at sexual or reproductive maturity (female): 1 years.

Average age at sexual or reproductive maturity (male): 1 years.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (External ); oviparous

Johnny darter eggs are attached to the underside of rocks and guarded by males until they hatch. Males rub the eggs with their fins to clean them from 13 to 16 times an hour. They also fan the eggs with their pectoral fins. When an eggs becomes covered with fungus, the male will eat it. Males aggressively defend their eggs against fish that might want to eat them.

Parental Investment: pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Protecting: Male)

Spawns April-June over most of range, but spawning peaks July to early August in Colorado (Propst and Carlson 1989); spawns mid-March to mid-May at southern limit of range in Mississippi (Parrish et al. 1991). Male guards eggs, which in Michigan hatch in 16 days in April, 10 days in May, and 6 days in June. Several females may contribute to egg mass of each male. Sexually mature in 1 year (Page 1983). In Colorado, few survived past age III (Propst and Carlson 1989).

Johnny darters are not considered threatened throughout most of their range. They are considered vulnerable or imperiled in some states, including Arkansas, Kentucky, Oklahoma, Kansas, and Nebraska. Johnny darters are tolerant of high levels of silt and some pollution and are able to colonize disturbed aquatic habitats readily.

IUCN Red List of Threatened Species: not evaluated

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

Johnny darters are not considered threatened throughout most of their range. They are considered vulnerable or imperiled in some states, including Arkansas, Kentucky, Oklahoma, Kansas, and Nebraska. Johnny darters are tolerant of high levels of silt and some pollution and are able to colonize disturbed aquatic habitats readily.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

There are no negative effects of Johnny darters on humans.

Johnny darters are important members of native aquatic ecosystems and are some of the first fish to colonize disturbed aquatic habitats. They are important prey for larger game fish.

There are no negative effects of Johnny darters on humans.

Johnny darters are important members of native aquatic ecosystems and are some of the first fish to colonize disturbed aquatic habitats. They are important prey for larger game fish.

Comments: Etheostoma susanae formerly was regarded as a subspecies of E. nigrum; mtDNA data support recognition of the two as distinct species (Strange 1998).

E. nigrum formerly included E. olmstedi as a subspecies (Lee et al. 1980). See Chapleau and Pageau (1985) for relationship between nigrum and olmstedi in Canada.