Umbra limi
| Central mudminnow | |
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Esociformes |
| Family: | Umbridae |
| Genus: | Umbra |
| Species: | U. limi |
| Binomial name | |
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Umbra limi Kirtland, 1841 |
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The central mudminnow (Umbra limi) is a small fish in the family Umbridae of the order Esociformes. It is found in central and eastern North America in productive waters. It is fairly tolerant of low oxygen concentrations and, as a result, it is sometimes the only, or one of a very few, fish species present in waters susceptible to winter or summer kill.
The central mudminnow lives in slow-moving water around ponds, lakes, and streams in central North America, and ranges in length from 51–102 mm. It burrows tail-first in mud and can tolerate low oxygen levels, allowing it to live in waterways unavailable to other fishes. Its coloration matches this habitat, being brownish above with mottled sides and a pale belly. It is eaten by many species of fish such as grass pickerel, sunfishes, northern pike, and catfishes; it is also preyed upon by birds, foxes, and snakes when caught out of water. According to Paszkowski and Tonn, mudminnows perform better in environments with other fish species than in environments with just mudminnows, because the "interspecific interactions override a similar contribution for the mudminnow, which is regarded as a fugitive species". Central mudminnows are known to eat a large variety of zooplankton and benthic and epiphytic macroinvertebrates. Adults are also known to feed energetically in the winter months on littoral fish. One experiment conducted by Colgan and Silburt resulted in mudminnows typically feeding more on benthic than plaktonic resources, with zooplankton making up only 0.7 of 511 items found in the stomach. This mudminnow uses a modified gas bladder to breathe air pockets trapped between the ice and water during the winter to feed and stay active.
Umbra limi is a widely distributed species that inhabits many freshwater systems such as lakes, streams, and wetlands near the littoral zone, or near the shore, and around dense cover in central North America west of the Appalachian Mountains, including the St. Lawrence River, Great Lakes, Hudson Bay (Red River, and the Mississippi River basins from Quebec to Manitoba and south to central Ohio, western Tennessee, and northeastern Arkansas. The central mudminnow has also been introduced into many of the tributaries in Connecticut and Massachusetts. Their habitats being marshy lands and rivers are under attack by human development and contact constantly and is likely causing a decline in their populations.
The central mudminnow is carnivorous and typically feeds in the benthic area of freshwater habitats. According to Colgan and Silburt, it prefers amphipods, coleopterans, and anisopterans while avoiding zooplankton and other planktonic species. In a study by Colgan and Silburt, they found that an average of only 0.9% of the contents of dissected stomachs of U. limi contained zooplankton. Chironoids and gastropods, when taken from the dissection, had a combined volume of about 60%, which proves that the mudminnow feeds mainly in benthic areas.
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Wikipedia