With the exception of spawning phase coloration, adult males and females look similar. The upper half of their bodies is dark greenish that gradually fades to a whitish belly. Small, randomly scattered dark spots are often present along the length of the body and the fins are generally colorless. During the spawning season, males develop a slate-gray colored back, a yellowish underside, and small dark spots on the pelvic fins. Females remain unchanged, although grayish bars may appear on the dorsal fins. The mouth, which is on the underside of their head, is pointed downwards which helps them eat algae on the river bottom. Maximum size is 287 mm total length and the average length is 102 mm. (Goldstein and Simon, 1999; Lennon and Parker, 1960; Miller, 1981; Rook, 1999)
Central stonerollers are found from New York west through the Great Lakes to Wisconsin and Minnesota and south through the Mississippi valley to Mexico. Though not listed as threatened in any of the United States, this species is uncommon in the Great Plains states.
There are three subspecies of central stonerollers that occur in specific locations. Campostoma anomalum anomalum is found in the Ohio River and upper Atlantic drainages, C. anomalum michauxi is found in the Santee and Savannah River drainages of Georgia, and C. pullum is found throughout the remainder of the range. (Miller, 1981; Page and Burr, 1991)
Central stoneroller preferred habitat is pools or riffles with gravel or rubble substrate in small to medium-sized streams. They prefer cool, clear water with moderate to fast currents. Newly hatched fish school together and feed on vegetation in stream edges, while juveniles are found in swift flowing water in pools or riffles with algae to feed on. Researchers have found that central stonerollers are very sensitive to water pollution or increased debris which may prevent algae from growing. If these occur, the fish may leave the area in search of better habitat. (Edwards, 1997; Miller, 1981; Sublette, et al., 1990)
Eggs are sticky and attach to gravel at the bottom of streams. At water temperatures optimal water temperature, eggs hatch in 69 to 72 hours. Central stonerollers continue to grow as they age, and can be 51 to 65 mm standard length by age 1, 79 to 104 mm by age 2, and to 226 mm by age 5. (Edwards, 1997; Lennon and Parker, 1960; Reed, 1958)
Depending on the stream, fish may migrate upstream, possibly into small streams, to find suitable spawning habitat. Central stonerollers may not migrate if suitable habitat is available in their current environment. Males appear first at spawning sites and begin to build multiple nests. During the construction of nests, males may work together to dig nests, which are typically 30.5 cm in diameter and approximately 7.5 cm deep. Nests are typically found near riffles, where water flows swiftly. To construct the bowl-shaped nests, males use a series of picking, digging, and pushing behaviors to remove gravel. During the nest building process, females typically gather nearby but rarely approach males. Once males have completed nest building, they become territorial and defend their nest(s) by chasing away any male that approaches, sometimes chasing the intruder out of the water onto the stream bank. Females roam the nest site, often darting in and out of many nests. Females stop to lay eggs in nests occupied by larger males. After the spawning period, males and females return to their normal habitat. Neither male nor female stay to guard the nest. (Miller, 1981; Simon, 1999)
Timing of the breeding season depends on the region. Central stonerollers spawn from mid-April to early June in the northern parts of their range and from mid-February to mid-July in populations in Texas. Some research has found that water temperature and day length trigger the start of the spawning season.
Central stonerollers often use the nests of other fish and will push other females out of their own nests. Central stonerollers have been observed using the nests of bluehead chub and rainbow trout. These fish may also hybridize with other species that breed at the same time of year such as
Along with superimposition, central stonerollers have been observed hybridizing with other species, often those with similar spawning seasons, including southern redbelly dace, striped shiner, Rio Grande chub, creek chub, and longlose dace.
It is estimated that mature females can lay 200 to 4800 eggs. Mature eggs are about 2.0 mm in diameter and approximately 2.4 mm in diameter after the eggs are expelled into water. Unfertilized eggs are a dull gray, while fertilized eggs are bright yellow. Eggs hatch after 69 to 72 hours.
Central stonerollers can reproduce at 2 or 3 years old throughout the northern geographic range, and typically at 3 to 4 years in the southern United States. (Edwards, 1997; Grady and Cashner, 1988; Miller, 1981; Schmulback, 1957; Sublette, et al., 1990)
Neither males nor females care for eggs after spawning. (Simon, 1999)
Little is known about the lifespan of central stonerollers, although a 6 year old individual has been observed in the Great Smokey Mountains National Park. No information is known about these fish in captivity. (Lennon and Parker, 1960)
Little is known about the behavior of central stonerollers, aside from reproduction. Some fish undergo migrations during spawning season to find suitable egg-laying habitat, whereas some individuals spend an entire year in the same pool. (Miller, 1981)
Home range size varies throughout their geographic range, depending on habitat conditions. In habitats that provide abundant food, shelter and other resources, fish will not need to travel far for these resources and will have small home ranges. In habitats where resources are scarce, fish will have to travel farther to obtain resources and will have larger home ranges.
Little is known about communication or perception in central stonerollers.
Central stonerollers are voracious feeders, with a diet largely consisting of algae. They can even leave permanent marks on limestone rocks that they graze on. Although their diet consists of 95% algae, they also consume detritus, diatoms, inorganic material, and blue-green algae. They consume small invertebrates as well. Central stonerollers adapt their diet in the presence of competitors. When larger, largescale stonerollers were present, central stonerollers will eat more inorganic material while the largescale stonerollers eat algae. (Evans-White and Dodds, 2003; Fowler and Taber, 1985; Matthews, et al., 1987; McNeely, 1987; Power and Matthews, 1983)
Primary predators include herons, bitterns, smallmouth bass, largemouth bass, and rock bass. Their brown coloration with dark spots resembles the rocky river beds that central stonerollers inhabit. This helps to camouflage them and avoid predators. (Power and Matthews, 1983)
Little is known about the role central stonerollers play in the ecosystem. It has been shown that central stonerollers have the ability to over-graze algae, possibly decreasing oxygen production in streams. Central stonerollers are preyed upon by many bird and fish species and thus help to support those predator populations. (Miller, 1981; Power and Matthews, 1983)
There are no known adverse effects of central stonerollers on humans, however, they may have negative effects on popular game-fish species such as rainbow trout. Female central stonerollers often take over other fishes' nests and may push rainbow trout away from their nests. Also, algae is a plant that completes photosynthesis to get rid of carbon dioxide and produces oxygen underwater. Many river organisms rely on oxygen and would suffer in an environment with too much carbon dioxide. If central stone rollers eat too much algae, it may make the environment unsuitable for other organisms in the ecosystem. (Miller, 1981)
Central stonerollers are of little economic importance to humans. Central stoneroller minnows are sometimes used as bait by fishermen. They are not caught specifically for human consumption. (Page and Burr, 1991)
Studies of central stonerollers have found their populations to be either secure or apparently secure in all but two states throughout their geographic range. In North Dakota they are listed as vulnerable and in Louisiana they are listed as imperiled. They are not listed as threatened or endangered. (Holm and Crossman, 2001)
Chris Gagnon (author), Northern Michigan University, Rachelle Sterling (editor), Special Projects, Jill Leonard (editor), Northern Michigan University, Tanya Dewey (editor), University of Michigan-Ann Arbor.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends.
uses smells or other chemicals to communicate
having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment; being difficult to see or otherwise detect.
animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature
union of egg and spermatozoan
mainly lives in water that is not salty.
An animal that eats mainly plants or parts of plants.
animals that have little or no ability to regulate their body temperature, body temperatures fluctuate with the temperature of their environment, often referred to as 'cold-blooded'.
Animals with indeterminate growth continue to grow throughout their lives.
referring to animal species that have been transported to and established populations in regions outside of their natural range, usually through human action.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
makes seasonal movements between breeding and wintering grounds
having the capacity to move from one place to another.
specialized for swimming
the area in which the animal is naturally found, the region in which it is endemic.
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
the kind of polygamy in which a female pairs with several males, each of which also pairs with several different females.
breeding is confined to a particular season
remains in the same area
reproduction that includes combining the genetic contribution of two individuals, a male and a female
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
uses sight to communicate
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