Banded sculpin

Banded sculpin
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Scorpaeniformes
Family: Cottidae
Genus: Cottus
Species: C. carolinae
Binomial name
Cottus carolinae
T. N. Gill, 1861

The banded sculpin (Cottus carolinae) is a freshwater fish dwelling mostly in small to moderate sized streams in areas of swift current. Young and juvenile C. carolinae can mainly be found in pools, riffles, and other shallow habitats while adults tend to prefer deeper waters. Mating and nesting for the sculpin is in spring, with males carefully guarding the eggs until they hatch.[1]

C. carolinae primarily eats insects and insect larvae such as Ephemeropterans, or the may fly, with little predation on other fish and crustaceans. Their large mouths enable them to eat prey nearly as large as themselves, including other sculpin.[2] C. carolinae itself is preyed upon by larger fish, most significantly Trout. To prevent predation, the color and pattern of the sculpin tends to match its environment. Most Cottus carolinae are mottled brown with dark vertical banding and usually reach about three inches in length. They have a broad head which rather quickly narrows into a slim body, giving them the appearance of a tadpole reaching adulthood.

C. carolinae has proven to be useful as a representative species for the effects of mining related impacts on fishing communities since it has been proven that their density is negatively correlated with higher metal concentrations from mining.[3] In other areas around the Cumberland Basin, as a benthic fish, the C. carolinae is in danger of increased siltation by area farming. Though the sculpin faces these threats, they are not yet on the list of endangered species.[4]

Distribution

Cottus carolinae is a freshwater species dwelling within the United States. The wide-ranging species occurs in eastern North America west of the Appalachians and south of the Ohio River Valley.[1] The species lives as far south as the mountain streams of Alabama, but prefers the cooler streams of the mid to northern United States.[5] Though they occupy such a large portion of the United States, they have a small home range of about forty-seven square meters.[4] C. carolinae can live in streams, rivers, and have even become adapted for cave life in underground springs.[6] The species is intolerant to habitat changes, and has experienced some limitations due to the effects of pollution. The largest pollutant threat to Cottus carolinae habitat is siltation of rivers and streams. Additionally, water impurities such as mining-derived metals in areas of Missouri have posed a high enough threat to populations that numbers have dwindled in those areas.[2]

Ecology

Cottus carolinae usually inhabits streams and rivers with cool, running water. They are a benthic species and prefer stream beds made of sand bedrock, stones, or boulders. C. carolinae partake in size-specific habitat segregation, with the majority of adults in the pools of streams and rivers with the young-of-the-year inhabiting the riffles.[7] Most streams inhabited by the species are less than two meters deep with a velocity between .1 and .7 meters per second with a standard deviation of + or - .2 meters per second.[4]

C. carolinae is primarily a nocturnal ambush predators and subsists largely off of a diet of insects and insect larvae, though they are opportunistic feeders and have been known to feed on one another.[8] 39% of their diet consists of Ephemeropterans, followed closely by dipterans, which make up 30% of their diet.[2] The greatest risk of predation for larger C. carolinae is posed by piscivorous mammals, reptiles, and birds, which lead to the habitat shift from shallow riffles to deeper pools into adulthood.[7] Their largest concern with respect to competition is for rock shelters with other species such as crayfish. Other factors that reduce the abundance of C. carolinae include habitat change and pollution.

Life history

Mating and nesting for C. carolinae begins in early spring. Spawning is triggered by a spike in water temperature of about fifty degrees Fahrenheit. Though the temperature spike does not have to be maintained for continued spawning, it is necessary for spawning activation.[7] In preparation for the spawning period, some males will darken in coloration, though this is less common in Cottus carolinae and more common in other Cottus species’, such as Cottus bairdii.

The spawning period for Cottus carolinae is short, lasting less than two weeks. Spawning occurs underneath stones or other objects and eggs are deposited in large clumps. Fecundity averages 465 ova per female. Once spawning is complete, males guard the nests. Some very attentive males groom out bad eggs while eggs in the clutches of less attentive males are sometimes preyed upon by opportunistic bacteria and fungi. Most male Cottus carolinae begin reproduction at the age of two years or beyond, with females beginning to reproduce slightly sooner. The lifespan of Cottus carolinae averages four years.[9]

Current Management

The United States Environmental Protection Agency has Cottus carolinae listed as intolerant to habitat destruction and intermediately intolerant to pollution. As a species that feeds and reproduces benthically, C. carolinae is more vulnerable to stream degradation that non-benthic species. Because of this pollution sensitive nature, the species is often used as an indicator of stream health.[10] Studies have shown that populations of C. carolinae decrease in the presence of silts, pollution, and disturbance and it has been shown in the past that C. carolinae densities are negatively correlated with water metal concentrations.[9] Though there is not a huge threat to the species from invasive species, excess trout introduction in some areas has reduced species numbers.

Currently, Cottus carolinae is not listed as threatened or endangered by the United States Fish and Wildlife Services, nor is it on the IUCN Red List. Though some studies have been done to determine the effects of siltation and mining-related metal concentrations, there are currently no large conservation efforts in place for Cottus carolinae due to its absence from any threatened or endangered species lists. In the future, human impact can be reduced by managing the effects of farming on siltation and devising a way to prevent run-off water containing mining-related metals from flowing into streams and rivers.

References

  1. 1 2 Cathy Koczaja, Laura McCall, Elizabeth Fitch, Brad Glorioso, Chad Hanna, Juliana Kyzar, Matthew Niemiller, Jeremy Spiess, Amy Tolley, Richie Wyckoff, and Dennis Mullen. 2005. Size-Specific Habitat Segregation and Intraspecific Interactions in Banded Sculpin (Cottus carolinae). Southeastern Naturalist 10: 207-218
  2. 1 2 3 Renn Tumlison and George R. Cline. 2002. Food Habits of the Banded Sculpin (Cottus carolinae) in Oklahoma With Reference to Predation on the Oklahoma Salamander (Eurycea tynerensis). Proceedings of the Oklahoma Academy of Science 82:111-113
  3. ↑ US Environmental Protection Agency. 2011. Effects of mining-derived metals on riffle-dwelling benthic fishes in Southeast Missouri, USA. http://hero.epa.gov/index.cfm?action=search_new.view&reference_id=447909.
  4. 1 2 3 Brooks M. Burr, Ginny L. Adams, Jean K. Krejca, Regina J. Paul and Melvin L. Warren. 2001. Troglomorphic Sculpins of the Cottus carolinae Species Group Perry County, Missouri: Distribution, External Morphology, and Conservation Status. Environmental Biology of Fishes 62:279-296
  5. ↑ James D. Williams and C. Richard Robins. 1970. Variation in Populations of the fish Cottus carolinae in the Alabama River System with Description of a New Subspecies from below the Fall Line. American Midland Naturalist 83: 368-381.
  6. ↑ Larry A. Greenberg and David A. Holtzman. 1987. Microhabitat Utilization, Feeding Periodicity, Home Range and Population Size of the Banded Sculpin, Cottus carolinae. Copeia 1:19-25.
  7. 1 2 3 C.L. Ruble, P.L. Rakes, and J.R. Shute. 2009. Propagation Protocols for the Banded Sculpin, Cottus carolinae. Virginia Department of Game and Inland Fisheries 1-8.
  8. ↑ Edward Phillips and Raj V. Kilambi. 1996. Food habits of four benthic fish species (Etheostoma spectabile, Percina caprodes, Noturus exilis, Cottus carolinae) from northwest Arkansas streams. The Southwestern Naturalist 41:69-73.
  9. 1 2 University of Michigan Museum of Zoology. Animal Diversity Web: Cottus carolinae. University of Michigan. http://141.213.176.11/site/accounts/information/Cottus_carolinae.html.
  10. ↑ US Environmental Protection Agency. 2010. Biological Indicators of Watershed. http://www.epa.gov/bioiweb1/html/fish_sculpins.html. Proceedings of the Oklahoma Academy of Science 82:111-113.
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