| Clear Creek gambusia | |
|---|---|
| |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Actinopterygii |
| Order: | Cyprinodontiformes |
| Family: | Poeciliidae |
| Genus: | Gambusia |
| Species: | G. heterochir
|
| Binomial name | |
| Gambusia heterochir C. Hubbs, 1957
| |
The Clear Creek gambusia (Gambusia heterochir) is a species of fish in the family Poeciliidae endemic to the United States, particularly Menard County, Texas.[3]
YouTube Encyclopedic
-
1/2Views:1 2821 747
-
Southern Tessellated Darter
-
Darters
Transcription
We're trying to better describe distribution, occurrence, and abundance of southern tessellated darter in Florida. They are an imperiled species. And really there is not a whole bunch known in Florida about where they occur. They've only been found, historically, in six locations. Those locations have all been in the Ocklawaha River basin. So anyways, this species is...there's an isolated population in Florida, and they don't...are not known to occur again until you get to Altamaha River basin in Georgia. With this management plan being written and not much known about where they are at in Florida, we've decided to actually go out and target the species. We're kick-seining. We're using this seine and a backpack electrofisher. So...two people hold the seine and one person has a backpack on, and we put electricity into the water. And to make that current and help the fish go into the seine we kick the water, that's how we're sampling. "We got, we got!" "We got a darter!" And at each one of those locations we sample 50 meters of...of the stream. Then we take a habitat parameter, like velocity and substrate and depth and stream width. Another thing we're doing is keeping track of all of the species that we get at each site. And keeping track of all the darters and how many darters we find at each site. So, we've worked with GIS analyst out of Tallahassee with FWC, Mark Barrett, and he mapped different tributaries and distributaries of Ocklawaha River from Silver River all the way down to St. John's River. We've randomly picked a number of locations in each one of those areas to go out. We're working cooperatively with USGS, Howard Jelks, U.S. Geological Survey in Gainesville, and Jim Austin out of University of Florida. People are helping us out up in Georgia, and than South Carolina and North Carolina. They are collecting tessellated darters. We are going to compare the population in Florida to those populations. We don't have an estimate of how many southern tessellated darters are in Florida. That's the next phase of this project. So far to date we've only found fifteen. In the areas that we actually find them we're going to go back and get estimates of how many darters there are per length of the stream to get an abundance estimate.
Habitat and biology
The Clear Creek gambusia inhabits the headwaters of Clear Creek which are derived from springs with clear, acidic water and having a constant temperature. It occurs in area where there is a growth of Ceratophyllum, an aquatic plant, which is also home to this fish's main prey item, the endemic amphipod Hyalella taxana. The submerged vegetation also gives the gambusia cover from its predators. This is an ovoviviparous species and the young are born live. Most births occur between March and September. The fish live their entire lives in the clear spring waters of the Clear Creek tributary of the San Saba River. The fish congregate around submerged aquatic vegetation that provides them with food and shelter.[4]
Conservation
The range of the Clear Creek gambusia was shrunk due to the construction of dams which allowed western mosquitofish (Gambusia affinis) to displace them, as the construction of the dams resulted in a greater variation in water temperatures which the western mosquitofish could tolerate better than the Clear Creek gambusia. By 1979 the last remaining population was protected from competing congeners by being upstream from a dam, below which the waters were populated by mosquito fish. The dam had been damaged by the activities of nutria (Myocastor coypus) and by the growth of tree roots, and hybridization between the Clear Creek gambusia and the western mosquitofish was detected. The dam was repaired, the population increased and in 1985 large numbers of Clear Creek gambusia were detected below the dam. The waters below the dam now had populations of rainwater killifish (Lucania parva), a species not native to the area and thought to be introduced as discarded fishing bait, however, it is thought that the rainwater killifishes outcompeted the western mosquitofish, allowing the Clear Creek gambusia to expand downstream of the dam. The Clear Creek gambusia was put on the United States' list of endangered species in 1967.[4]
References
- ^ NatureServe (2013). "Gambusia heterochir". IUCN Red List of Threatened Species. 2013: e.T8892A18232529. doi:10.2305/IUCN.UK.2013-1.RLTS.T8892A18232529.en. Retrieved 17 November 2021.
- ^ "Gambusia heterochir - Hubbs, 1957". NatureServe Explorer. Retrieved 2 November 2019.
- ^ Froese, Rainer; Pauly, Daniel (eds.) (2019). "Gambusia heterochir" in FishBase. August 2019 version.
- ^ a b "Clear Creek Gambusia (Gambusia heterochir)". Texas Parks and Wildlife. Retrieved 2 November 2019.
 | This Cyprinodontiformes article is a stub. You can help Wikipedia by expanding it. |
This page was last edited on 19 April 2023, at 23:36