Semotilus atromaculatus
| Semotilus atromaculatus | |
|---|---|
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| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Cypriniformes |
| Family: | Cyprinidae |
| Genus: | Semotilus |
| Species: | S. atromaculatus |
| Binomial name | |
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Semotilus atromaculatus (Mitchill, 1818) |
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Semotilus atromaculatus, known as the creek chub or the common creek chub, is a small minnow, a freshwater fish found in the eastern US and Canada. Differing in size and color depending on origin of development, the creek chub can usually be defined by a dark brown body with a white lateral line spanning horizontally across the body. It lives primarily within streams and rivers. Creek Chubs attain lengths of 2-6 inches with larger specimens of up to 12 inches possible. The genus name Semotilus derives from the Greek word sema (also known as dorsal fin), and atromaculatus comes from the Latin word "black spots".
A fish which can withstand many different environments, the creek chub's current range is the eastern two-thirds of the US and southeastern Canada. It can quickly adapt to different extreme environments, and can live on many different foods. Documented to span throughout the Great Lakes surrounding Wisconsin, and into Minnesota, this species has been described as plentiful. However, reports of this species have fallen throughout Wisconsin and the Great Lakes, suggesting a decline in its population in these regions.
Though populations have been declining within the Great Lakes, they have been continually documented throughout small and medium rivers and streams. Thriving in small stream environments, the creek chub gravitates toward areas of weeds to appear secure and avoid predation. Varying in environments containing a multitude of substrates, they have been documented over gravel, sand, silt, rubble, mud, boulders, clay, bedrock and detritus bottoms. This fish actually prefers the stream or river environment compared to that of a lake, as they have been recorded in streams far more than lakes. Of over 440 individuals caught, only 9 were from lakes, and when limiting the locations to solely lakes, only six individuals were caught.
The creek chub is a small chub with a greenish-brown back, cream-colored sides interrupted by horizontal black stripes running from the nose to the tail, and a white belly. Having a round, cylindrical body with a compressed posterior, males average 125 mm in length, while females average 105 mm. As the specimen eats what is directly in front of it, the mouth is terminal, large and under the anterior of the eye.
The creek chub has been known to slightly differ in coloration, containing black backs with a brown or yellowish middle lines. The average chub ranges in size from 5-7 inches in length, with the largest chub documented to be 197 mm long. They can be identified from other common minnow species by the black "moustache" on their upper lips, along with a black dot on their dorsal fins. Additionally, juvenile males develop a rosy band on their sides, along with glossy, dark dorsal fin spots.
The scales of this species are quite unique to the needs of the creek chub, ultimately helping to protect and maneuver. Scales do not appear until the fish is 26 mm long, leaving 30-mm-long individuals having small scales with few circuli. Major growth occurs during the first year, often jumping by over 50–70 mm in one year. Males grow far more quickly than females, allowing maturity to occur at one to one and a half years of age.
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Wikipedia