Redspotted sunfish

Redspotted sunfish
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Centrarchidae
Genus: Lepomis
Species: L. miniatus
Binomial name
Lepomis miniatus
(D. S. Jordan, 1877)

The redspotted sunfish (Lepomis miniatus) is a species of freshwater demersal fish native to the United States.[2]

Geographic distribution

The redspotted sunfish is a freshwater fish that can be found throughout the Mississippi River Valley. The distribution spreads north into Illinois and to the Ohio river, west into Texas and to Oklahoma's Red River, and east to the Chattahoochee River in Georgia.[3] Currently the populations of Lepomis miniatus found in the southern United States seem to be stable.[3] However, the species numbers have diminished significantly in the state of Illinois which lies at the northernmost point of the fish's historic range. Once the redspotted sunfish was found in bodies of water throughout the state but the species range is now limited to just a few counties in the southern portion of Illinois.[4] In fact surveys conducted in the mid-2000s suggested that just two populations existed in the entire state at the time.[5] There could be a number of causes for the decrease in the Lepomis miniatus in Illinois. A popular theory is that the redspotted sunfish has struggled due to a loss of wetlands, which make up the sunfish's natural habitat. The population may also be declining due to increasingly poor water conditions or from competition with invasive species.[6]

Ecology

Lepomis miniatus feeds primarily on benthic species. Zooplankton make up between 33.3% to 74.6% of the diet of small sunfishes, about 50% of the diet of medium-sized sunfishes as they introduce larger prey into their diet. At larger sizes the redspotted sunfish shifts primarily to benthic macrofauna.[7] Many larger carnivorous fish feed on the redspotted sunfish, primarily bass.[8] Lepomis miniatus is commonly found in shallow and highly vegetative water. The species seems to prefer areas of slow moving water, 0.4 cm/s.[3] While the redspotted sunfish has been shown to compete with other sunfish and some invasive species, like the Rio Grande cichlid in Louisiana, this competition is thought to have little effect in most cases due to the generalist diet of Lepomis miniatus.[9] A more direct danger could be invasives who force the Lepomis miniatus out of its preferred habitat, thus increasing the risk of predation.[8] Human induced changes that might affect the redspotted sunfish could be the reduction in habitat itself, seeing as how they inhabit smaller bodies of water due to their preference for shallow, vegetative, water. They also might directly hurt the water quality through pollution, like in the case of the Wabash River in Illinois which saw the species decline possibly due to oil pollution.[4]

Life history

The breeding time of the redspotted sunfish varies across the range of the species but usually occurs in late spring or early summer. The fish breeds in shallow, shaded, areas close to the shore in nests constructed by the males. The redspotted sunfish has an average clutch size of around 2000.[10] Lepomis miniatus reaches sexual maturity at lengths greater than 50–55 mm TL, which occurs sometime between the ages of one and two.[10] The average lifespan of the Lepomis miniatus is about five to six years, six being the maximum age the species tends to reach.[10] The effect of human induced changes on this life history is unknown at this time.

Conservation and management

Decimation of the sunfish was probably the result of drainage of swamps and bottomland lakes and the general deterioration of the water quality.[5] There is some concern that the release of the invasive Nile tilapia into waters inhabited by the redspotted sunfish could be detrimental to the species.[8]

In Illinois the redspotted sunfish has been listed as endangered in that state. Fortunately a number of organizations have been working to help the species recover and are hoping to get the sunfish's status reduced to threatened in Illinois by 2014.[5] The main groups who are working to rehabilitate Lepomis miniatus are the Nature Conservancy in conjunction with the Illinois Natural History Survey and the Illinois Department of Natural Resources.[6] These conservation efforts have involved transplanting a portion of the redspotted sunfish population into two protected, suitable, bodies of water. The first being a preserve lake in Emiquon Nature Preserve and the second being a refuge pond in Allerton Park. These populations have spawned enough fish to stock five more suitable bodies of water.[5]

The redspotted sunfish is listed as an endangered species in the state of Illinois.[11] It is being reintroduced into the Emiquon National Wildlife Refuge near Havana, Illinois.[12]

References

  1. ↑ NatureServe (2015). "Lepomis miniatus". IUCN Red List of Threatened Species. Version 4.1 (4.1). International Union for Conservation of Nature. Retrieved February 25, 2016.
  2. ↑ Froese, Rainer and Pauly, Daniel, eds. (2011). "Lepomis miniatus" in FishBase. July 2011 version.
  3. 1 2 3 Williams, C.H. and T.H. Bonner. Lepomis miniatus. Texas Freshwater Fishes. Texas State University - San Marcos. n.d. Web. Retrieved 11 November 2012. http://www.bio.txstate.edu/~tbonner/txfishes/lepomis%20miniatus.htm
  4. 1 2 Nyboer, R.W., J.R. Herkert, and J.E. Ebinger. Endangered and Threatened Species of Illinois: Status and Distribution, Vol 2: Animals. Illinois Endangered Species Protection Board. p. 75. 2004 Web. Retrieved 11 November 2012. http://dnr.state.il.us/ORC/WildlifeResources/theplan/PDFs/2%20From%20Threatened%20&%20Endangered%20Species%20of%20Illinois.pdf
  5. 1 2 3 4 The Redspotted Sunfish Saga: From Statewide Surveys to Genetic Analyses, Captive Propagation, and Reintroduction Efforts. n.d. Web. Retrieved 11 November 2012. http://www.midwestfw.org/documents/FisheriesAbstracts.pdf
  6. 1 2 Great Rivers: Restoring Wetlands Gives Fish a Fighting Chance. The Nature Conservancy. 07 March 2011 Web. Retrieved 11 November 2012. http://www.nature.org/ourinitiatives/habitats/riverslakes/howwework/restoring-wetlands-gives-fish-a-fighting-chance.xml
  7. ↑ VanderKooy, K.E., C.F. Rakocinski, and R.W. Heard. 2000. Trophic relationships of three sunfishes (Lepomis spp.) in an estuarine bayou. North American Journal of Fisheries Management. Vol 23-5: 621-632.
  8. 1 2 3 Martin, C.W., M.M. Valentine, and J.F. Valentine. 2010. Competitive Interactions between Invasive Nile Tilapia and Native Fish: The Potential for Altered Trophic Exchange and Modification of Food Webs. PLOS ONE. Vol 5-12: Article e14395.
  9. ↑ Lorenz, T.O., M.T. O'Connell, and P.J. Schofield. 2011. Aggressive interactions between the invasive Rio Grande cichlid (Herichthys cyanoguttatus) and native bluegill (Lepomis macrochirus), with notes on redspotted sunfish (Lepomis miniatus). Journal of Ethology. Vol 29-1: 39-46
  10. 1 2 3 Wallus, R. and T.P. Simon. Reproductive Biology and Early Life History of Fishes in the Ohio River Drainage, Vol 6: Elassomatidae and Centrarchidae. p. 234-239. n.d. Web. Retrieved 11 November 2012. https://books.google.com/books?id=uZ2rHfYHYncC&pg=PA20&dq=%22Reproductive+biology+and+early+life+history+of+fishes%22+%22redspotted+sunfish%22&hl=en&sa=X&ei=84CpULHLLoqu9ATAnIHAAw&ved=0CC0Q6AEwAA#v=onepage&q=redspotted&f=false
  11. ↑ Mankowski, A., ed. (2010). "Endangered and Threatened Species of Illinois: Status and Distribution, Volume 4 - 2009 and 2010 Changes to the Illinois List of Endangered and Threatened Species" (PDF). Illinois Endangered Species Protection Board. p. 29. Retrieved 10 December 2011.
  12. ↑ "Redspotted Sunfish (Lepomis miniatus) reintroduction to Illinois sites of historical distribution" (PDF). Illinois Department of Natural Resources. Retrieved 10 December 2011.
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