Cottus carolinae

Geographic Range

Cottus carolinae (banded sculpin) is distributed in fourteen states within the southeastern and midwestern United States. The species occupies upland streams within the Mississippi River basin from the New River drainage in West Virginia and Virginia, west to Ozark Mountain drainages in southern Missouri and Kansas, and from southern Indiana and Illinois, south to northern Arkansas, Alabama, and northeast Georgia (Page and Burr, 1991; NatureServe, 2005).

• Biogeographic Regions
• nearctic nearctic
  • native native

Habitat

Banded sculpins are freshwater fish that inhabit streams of all sizes, ranging from small streams to large upland rivers. Individuals of this species occupy clear, cool to warm water and are frequently found in springs and caves. They are found in various velocities of water but prefer the gravel and rubble of riffles where their dark and pale dorsal coloration camouflages them from potential predators (Koczaja, et al., 2005; Etnier and Starnes, 1993; NatureServe, 2005).

In a study conducted on a stream in the Cumberland River Basin, Tennessee on “size-specific habitat segregation and intraspecific interactions” affecting habitat choice in banded sculpins, adults were found almost exclusively in the pools, while young-of-the-year were almost always found in riffles, and juveniles were found in both habitat types. Young-of-the-year preferred shallow habitat, both alone and when in the presence of an adult. Juveniles preferred deep habitat when no adult was present but chose shallow habitat in the presence of an adult. An explanation for this habitat preference is that juveniles may see adult banded sculpins as potential predators and may compete for refuges in the pools. Since banded sculpins are reported to be nocturnal foragers and the study was conducted during the morning, the results of the study correspond to refuge habitat use, as opposed to feeding habitat use of banded sculpins (Koczaja, et al., 2005).

• Habitat Regions
• temperate temperate
• freshwater freshwater

• Aquatic Biomes
• benthic benthic
• rivers and streams

• Other Habitat Features
• caves

Physical Description

Banded sculpins are bottom-dwellers with somewhat dorsally depressed bodies. Maximum total length is 18 centimeters (7.25 inches). The flattened body and large pectoral fins provide hydrodynamic adaptations to swift waters. These adaptations help the fish maintain position as it is pressed to the streambed by the overhead flow of water. Nonbuoyancy is acheived by the lack of a swimbladder (Etnier and Starnes, 1993). In general, sculpins have few or no scales. Ground color is most often rusty brown with four dark dorsal saddles (Etnier and Starnes, 1993). The last three saddles extend onto the sides as sharply defined bars (Page and Burr, 1991). The color of the body varies depending on the substrate and water clarity (Etnier and Starnes, 1993). The chin is mottled with dark pigment. The lateral line is complete, usually with 29 to 34 pores. There are 3 preopercular spines. The dorsal fins separate to the base (Page and Burr, 1991). The dorsal fin has 7 to 8 spines and 15 to 18 soft rays. The edge of the spinous dorsal fin is rust colored like the body but may be tinged with red in some spring habitats. The anal fin ray count is 12 to 14. Pectoral fin rays number 15 to 17 (Etnier and Starnes, 1993). There are 4 pelvic rays (Page and Burr, 1991). Principal caudal fin rays range from 10 to 12. Palantine teeth are well developed (Etnier and Starnes, 1993).

• Other Physical Features
• ectothermic ectothermic
• heterothermic heterothermic
• bilateral symmetry bilateral symmetry

• Sexual Dimorphism
• sexes colored or patterned differently

Development

Other than discussion of habitat, there is little discussion in the literature on the life cycle of banded sculpins. Small young inhabit quiet shallow areas and areas covered in detritus (Etnier and Starnes, 1993). Sometime between their first and second year of life, banded sculpins transition from shallow riffles to deeper, pool areas. This shift is attributed to a change in predation risk from piscivorous fish to avian and terrestrial predators (Koczaja, et al., 2005). A study by Craddock on Kentucky populations showed growth to be highly variable, with total lengths at ages 1 to 3 being 50 to 80 mm, 100 to 130 mm, and over 160 mm, respectively (Etnier and Starnes, 1993).

Reproduction

No information was found on the mating system of banded sculpins.

Spawning occurs beneath stones or other objects where the eggs are deposited in large clumps. This takes place in winter and early spring at temperatures between 9 and 14 degrees Celsius. Fecundity averages 475 ova per female. The male guards the nest. Most reproductive females are 2 or more years old (Etnier and Starnes, 1993; NatureServe, 2005).

• Key Reproductive Features
• iteroparous iteroparous
• seasonal breeding seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual sexual
• fertilization fertilization
  • external external
• oviparous oviparous

After eggs are deposited, the male banded sculpin guards the nest (Etnier and Starnes, 1993).

• Parental Investment
• pre-hatching/birth
  • protecting
    • male

Lifespan/Longevity

Maximum life span is estimated at 4 years (Etnier and Starnes, 1993).

Behavior

Banded sculpins are primarily nocturnal (NatureServe, 2005). They reside under rocks during the day and on top of rocks at night. A study conducted along the Little River of eastern Tennessee illustrated that sculpins moved from beneath rocks to the tops of rocks at dusk, and they returned under the rocks at dawn (Greenberg and Holtzman, 1987). Bottom-dwelling sculpins (Family Cottidae ) use their small, closely spaced pelvic fins as antiskid devices to cling to river bottoms (Moyle and Cech, 2004).

• Key Behaviors
• natatorial natatorial
• nocturnal nocturnal
• motile motile
• sedentary sedentary
• solitary solitary

Home Range

Banded sculpins are neither locally migrant or long distance migrants (NatureServe, 2005). A study involving underwater counts of marked sculpins suggests the species has a small average home range, up to a maximum of 47 square meters (or 6.0 m of stream length) (Greenberg and Holtzman, 1987).

Communication and Perception

During the breeding season, males may become darkened or exhibit dark or red coloration in the spinous dorsal fin. These color changes are typical of mottled sculpins ( Cottus bairdii ) but may be absent or less pronounced in banded sculpins (Etnier and Starnes, 1993). Ground body color changes to match the substrate. For example, specimens from streams with chert gravel substrates may be brown, white, or pale green, while those from streams with other types of gravel may be the characteristic rusty brown with dark saddles (Etnier and Starnes, 1993). The literature reviewed does not comment on communication within the species, but it is likely that some visual cues are employed.

• Communication Channels
• visual visual

• Perception Channels
• visual visual
• tactile tactile
• chemical chemical

Food Habits

Both adults and immature banded sculpins are invertivores and piscivores (NatureServe 2005). They are nocturnal feeders and make effective use of their cryptic coloration when they stalk or ambush prey. Young banded sculpins consume aquatic insect immatures, including caddisflies (especially hydropsychids ), mayflies ( Ephemeroptera ), and midge larvae ( Chironomidae ). Adults prefer larger prey such as large stonefly nymphs ( pteronarcids , perlids , and perlodids ), other aquatic insects, crayfish ( Astacoidea ), salamanders , and small fish, especially other benthic riffle species such as darters (Etnier and Starnes, 1993).

In a study on the food habits of four benthic fish species (including banded sculpin, orangethroat darter ( Etheostoma spectabile ), logperch ( Percina caprodes ), and slender madtom ( Noturus exilis )) from northwest Arkansas streams, chironomids comprised the greatest portion of the diet of banded sculpins in numbers, but crayfish were the most abundant item by volume. Indices used in the study indicated active selection for crayfish as prey. Some seasonal variation in diet was also observed. Small size classes of banded sculpins consumed large numbers of small prey, while large size classes fed on fewer but larger prey. The study showed banded sculpins to have a relatively narrow variation in diet. Banded sculpins and slender madtoms appeared to be the most seasonally opportunistic feeders of the species studied (Phillips and Kilambi, 1996).

In a study involving feeding periodicity of banded sculpins in the Little River of eastern Tennessee, behavioral observations and gut content analyses suggest that the species is primarily a nocturnal feeder. Mean weight of ingested food was greater at night than during the day. None of the sculpins collected at night had empty stomachs, but 53% of the sculpins collected during the day did (Greenberg and Holtzman, 1987).

• Primary Diet
• carnivore carnivore
  • piscivore piscivore
  • insectivore insectivore

• Animal Foods
• amphibians
• fish
• insects
• aquatic crustaceans

Predation

Banded sculpins are cryptic in coloration and behavior. Their coloration mimics the stream substrate, which is a beneficial adaptation since they are primarily nocturnal ambush predators (Koczaja, et. al., 2005).

A study conducted by Koczaja, et al. (2005) in a Cumberland River Basin stream in Tennessee showed that the presence of adult banded sculpins affected the habitat preference of juvenile banded sculpins. Juveniles were more likely to use pool habitat in the absence of adults. Adults may represent a potential predator to juveniles and/or a competitor for refuges in pools. The study suggests that this is not likely a function of food availability since many prey items of small banded sculpins prefer the faster velocities of riffles. Adults showed preference for pool habitats. Predation risk from birds, mammals, and/or reptiles is the best explanation for the depth preference of adult banded sculpins. Despite their cryptic coloration, banded sculpins are susceptible to predation by piscivorous birds such as belted kingfishers and great blue herons . This risk is minimized by banded sculpins' use of deeper pool habitats. Large piscivorous fish, which inhabit deep pools, are the greatest predation risk to smaller sculpins (Koczaja, et. al., 2005).

• Anti-predator Adaptations
• cryptic cryptic

Ecosystem Roles

Banded sculpins are invertivores and piscivores, feeding primarily on aquatic insect larvae, crayfish, and small fish. They are considered benthic since they feed at the bottom of streams (NatureServe, 2005). As predators, they feed primarily at night by stalking or ambushing prey (Etnier and Starnes, 1993).

Economic Importance for Humans: Positive

Banded sculpins are generally sensitive to pollution and are considered intolerant of water quality impairment. Due to their low tolerance for poor quality water, banded sculpins are used as indicators of stream health. The species has been incorporated into a metric used to calculate the Index of Biotic Integrity, which measures stream health based on the fish community (Kentucky Department for Environmental Protection - Division of Water, 2002).

Economic Importance for Humans: Negative

There are no known adverse affects of the banded sculpin on humans.

Conservation Status

Banded sculpins are not listed by the United Sates Fish and Wildlife Service as threatened or endangered. There are no records for the banded sculpin on the CITES-listed species database. The species is not listed on the IUCN Red List of threatened species.

Other Comments

Three subspecies of Cottus carolinae are recognized (Page and Burr, 1991). The genus name Cottus is an old name for "Miller’s thumb", the common name of these fishes in Europe, and the species name carolinae is in honor of Miss Caroline Henry, a friend of the species’ describer (Etnier and Starnes, 1993).

Additional Links

Encyclopedia of Life

Contributors

Tanya Dewey (editor), Animal Diversity Web.

Julie Clark (author), Eastern Kentucky University, Sherry Harrel (editor, instructor), Eastern Kentucky University.

References

Etnier, D., W. Starnes. 1993. The Fishes of Tennessee . Knoxville, Tennessee: The University of Tennessee Press.

Greenberg, L., D. Holtzman. 1987. Microhabitat Utilization, Feeding Periodicity, Home Range and Population Size of the Banded Sculpin, Cottus carolinae. Copeia , 1: 19-25.

Kentucky Department for Environmental Protection - Division of Water, 2002. "Methods for Assessing Biological Integrity of Surface Waters in Kentucky" (On-line pdf). Accessed October 30, 2005 at http://www.water.ky.gov/NR/rdonlyres/B4F399A2-71EB-4CB7-A92A-A9EB2A3768BF/0/SOP_BiologicalIntegritySurfaceWater.pdf .

Koczaja, C., L. McCall, E. Fitch, B. Glorioso, C. Hanna, J. Kyzar, M. Niemiller, J. Spiess, A. Tolley, R. Wyckoff, D. Mullen. 2005. Size-Specific Habitat Segregation and Intraspecific Interactions in Banded Sculpin (Cottus carolinae). Southeastern Naturalist , 4/2: 207-218.

Moyle, P., J. Cech. 2004. Fishes, An Introduction to Ichthyology . Upper Saddle River, New Jersey: Prentice Hall, Inc.

NatureServe, 2005. "Comprehensive Report Species - Cottus carolinae" (On-line). NatureServe Explorer. Accessed October 23, 2005 at http://www.natureserve.org/explorer .

Page, L., B. Burr. 1991. A Field Guide to Freshwater Fishes . New York: Houghton Mifflin Company.

Phillips, E., R. Kilambi. 1996. Food Habits of Four Benthic Fish Species (Etheostoma spectabile, Percina caprodes, Noturus exilis, Cottus carolinae) from Northwest Arkansas Streams. The Southwestern Naturalist , 41/1: 69-73.