Central Stoneroller, Campostoma anomalum
Central Stoneroller, Campostoma anomalum. Fish caught from the Current River, Van Buren, Missouri, May 2016. Length: 5.1 cm (2.0 inches). Catch, photograph, and identification courtesy of Kenneth Tse, Toronto, Ontario, Canada.
Central Stoneroller, Campostoma anomalum. Fish caught in the Embarras River in southeast Illinois, June 2016. Length: 5.1 cm (2.0 inches). Catch, photograph, and identification courtesy of Josh Leisen (joshadventures.com), Gaylord, Michigan.
Central Stoneroller, Campostoma anomalum. Fish caught in a tributary of the Current River, Missouri, April 2014. Length: 9.5 cm (3.7 inches). Catch, photograph, and identification courtesy of Ben Cantrell, Peoria, Illinois.
Central Stoneroller, Campostoma anomalum. Fish caught in a tributary of the Current River, Missouri, April 2014. Length: 9.5 cm (3.7 inches). Catch, photograph and identification courtesy of Eli (obsessiveangling.wordpress.com).
Central Stoneroller, Campostoma anomalum. Fish caught from the Roanoke River, Roanoke, Virginia, June 2022. Length: 9.5 cm (3.7 inches). Catch, photograph and identification courtesy of James Lafontaine, Long Island, New York.
The Central Stoneroller, Campostoma anomalum, is a member of the Carp and Minnow or Cyprinidae Family, and is known in Mexico as rodapiedras del centro. They obtained their common name from the males’ habit of rolling stones along the bottom with their noses while nest building. Globally, there are six species in the Campostoma Genus, of which two are found in Mexico’s freshwater systems.
The Central Stoneroller is small in stature and has a stout cylindrical body. Males and females are of similar colorations. They are dark greenish dorsally gradually transitionIng to white ventrally. They have small randomly scattered dark spots along the length of the body. Their fins are generally colorless. During the spawning season, males develop a slate-gray colored back, a yellowish underside, small dark spots on the pelvic fins, black pigmented anal and dorsal fins and tubercles on their head, back and sides. Their head has a rounded snout and a subterminal mouth. The anal fin has 7 rays; the caudal fin is forked with rounded ends; their dorsal fin has 8 rays; their pectoral fins have 14 to 16 rays; and their pelvic fins have 8 rays. They have 26 to 35 gill rakers. They are covered with small scales.
Central Stonerollers are found in small to medium sized streams with cool, clear water and moderate to fast currents with pools or riffles with gravel or rubble substrate. They normally collect in schools containing several hundred individuals in mid-water or near the bottom. They reach a maximum of 28.7 cm (11.3 inches) in length. The Central Stroneroller is primarily an herbivore, feeding on filamentous algae, diatoms, and aquatic insects. In turn they are preyed upon by bitterns, herons, largemouth bass, rock bass and smallmouth bass. They rely on their cryptic coloration for camouflage to avoid predation. Central Stonerollers display some intolerance to heavy siltation or pollutants which may affect quantity of available algae in pool and riffle habitats. They are tolerant of low oxygen levels and water temperatures up to 33oC (92oF). They are known to migrate from environments that lack food and shelter. Reproduction is polygynandrous (promiscuous) in waters between 14.5oC (58oC) and 24oC (75oF). They are known to make seasonal migrations to find suitable breeding habitats. Reproduction is oviparous with external fertilization that involves annual breeding cycles. Some fish migrate upstream into small headwaters. They also hybridize with other species that breed at the same time of year. The male Central Stonerollers construct nests in gravel in the tailwaters of pools and at the heads of riffles in the main stream as well as small tributaries. The males are known to vigorously defend their nests as Central Stonerollers are known to take over nests of other fish. Each female enters the nest briefly to deposit between 200 and 4,800 eggs. Unfertilized eggs are dull gray; once fertilized they are bright yellow and adhesive. The eggs are covered with sand and gravel and being sticky, adhere to the gravel. The eggs are then abandoned by both parents and hatch in 69 to 72 hours. The newly hatched fish school together to feed in the warmer and more protected backwaters and vegetated stream margins in the late spring and early summer; juveniles frequently inhabit swifter waters around vegetated riffles during the summer and fall, and are commonly found in midstream habitats in pools having algal mats and moderately flowing currents. They have life spans of up to 6 years.
The Central Stoneroller is a resident of the freshwater systems of northeast Mexico that include the Rio Grande River and the Rio San Juan basin in Tamaulipas and Nuevo León. They are also found in Sonora presumably due to bait bucket releases.
The Central Stoneroller is similar in stature and appearance and can be confused with the Mexican Stoneroller, Campostoma ornatum (more lateral scales and a longer lower jaw).
From a conservation perspective the Central Stoneroller is currently considered to be of Least Concern with stable, widely distributed populations, although their habitats have been adversely affected by human development that alters water flow regimens, pollution and debris, and increased siltation and aquatic vegetation. They are not caught specifically for human consumption. They are utilized as a live bait by recreational fishermen. They have been introduced in many areas, primarily by bait bucket releases and are known to have a negative impact on native Rainbow Trout populations by destroying their nests, and decreasing the oxygen levels.