Phoxinus saylori

Phoxinus saylori
Conservation status
Endangered (ESA)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cypriniformes
Family:	Cyprinidae
Subfamily:	Leuciscinae
Genus:	Phoxinus
Species:	P. saylori
Binomial name
Phoxinus saylori C. E. Skelton, 2001
Synonyms
Chrosomus saylori

The Tennessee native minnow species Chrosomus saylori, previously known as Phoxinus saylori is named after its collector, Charles F. Saylor. It was first discovered in 1976.^[1] A very rare species, it has only been found in localized populations in six small streams on the Walden Ridge portion of the Cumberland Plateau in Tennessee.^[2] It is commonly considered a nest associate and uses its large mouth and short intestinal tract to support an animal-based diet. Displaying sexual dimorphism, an average adult C. saylori measures approximately 45 mm at the age of reproduction.^[3] Similar to other Chrosomus species, two dark parallel lines run the length of the body, and a red coloration appears during the breeding season. Spawning is believed to take place in small, cool streams, lined with small pebbles.^[4] As of August 9, 2011, this species was placed on the endangered species list, as a result of agriculture, mining, and timbering in the Walden Creek area.^[3]

Ecology

Because C. saylori is a relatively recent discovery, a detailed life study has not been performed. However, it is known to take shelter in the riparian zones of creek, where vegetation provides shelter. Because of this, it is extremely susceptible to changes, or the absence of such stream-side plants. They are generally found in cool, slow moving water, or pools containing small rocks, boulders, and rubble. This type of streambed is easily influenced by an increase in siltation. C. saylori are also susceptible to warmer water temperatures, above 25°C.^[3] The localized populations may be the result of pockets of the preferred, cooler water surrounded by warmer water.

After analyzing the stomach contents, it was found that the diet of C. saylori is mostly animal material. It was mostly benthic insect larvae, as well as plant material and sand grains. Similar to other fish species with animal-based diets, they have large mouths, short intestines, a reduced number of pharyngeal teeth, and a primitively shaped basiocciptial bone.^[5] C. saylori are often found feeding in loosely grouped schools.^[3]

Life History

This species is characterized by two, horizontal, uninterrupted black lines that run the length of the body which distinguish it from other similar species. Nuptial males have black pigment covering the breast and underside of head.^[6] Their intestines are loosely coiled in an S-configuration, and have a winged basioccipital pharyngeal pad, as opposed to rounded.^[3] Unfortunantly, very little is known about the reprocuctive strategies of C. saylori because so little is known about the species in general. The species has been observed spending time around gravel beds with small pebbles, as well as spending time around gravel-bed nests made by other species. Yet, it is still unclear as to what actually happens, apart from spawning in gravel beds.^[4] This trait alone, however, may be its downfall. Redds, or gravel/pebble spawning beds, are hugely impacted by any increase in siltation in the water. When the sediments sink and settle into these rocky areas, they can easily smother the eggs and ruin an entire breeding season. Therefore, this species is at a serious risk.

Current Management

Because this species is so rare, only to be found in six streams, it has been listed as an endangered species. As of 2007, the species was listed as a candidate. As of August 9, 2011, this species was officially listed as an endangered species.^[3] C. saylori is most threatened my an increase in siltation that can cause serious damage to spawning grounds. Such an increase can be caused by a variety of events, including the removal of riparian vegetation and timber removal progress in the nearby area surrounding these particular streams in which C. saylori can be found. In 1883, the Walden Ridge railroad moved into the area allowing for the transport of timber, which cause a boom in timber output.^[7] However, trees that stand near streams are responsible for holding the rich soil in place, preventing it from being washed away and eroded by the stream. The removal of such trees through mining often results in stream bank erosion, causing an increase in siltation. In addition, nearby mining practices are known to have bad stream side management zones and problems with roadside construction. Two current projects are of greatest concern for this species including the installation of a water line crossing through a populated creek, and building an impoundment on a tributary to an occupied stream.^[8] These activities result in great danger for the C. saylori species.

However, some efforts are being made to protect this fish. In 1992, an organization dedicated to aquatic conservation called Conservation Fisheries Inc. was established. It is responsible for monitoring and restoring at-risk populations such a C. saylori. They work throughout the southeast, using a variety of methods of management. Because the danger to this species is not yet dire, as they are still quite abundant in these areas, this organization is not currently taking action with C. saylori. They are able to raise them in hatcheries and are monitoring the populations, waiting for any indication of trouble.^[8]

Management Recommendations

Fortunately, because of its small distribution, C. saylori is already being monitored carefully. As mentioned previously, this species is potentially at risk, so Conservation Fisheries Inc is already watching it. However, further monitoring should still be performed in order to protect this species. Because this species is only found in six small streams, electro-shocking would probably be the best way to determine population densities.^[9] Only in small streams would this method actually give accurate approximate counts. Obviously all six streams known to have C. saylori populations should be sampled, as well as surrounding nearby streams to see whether or not this species distribution range might be increasing. Because so little is known about this species, a more in depth study should be performed to determine more about the life history of this fish. This will allow conservation efforts to make knowledgeable decisions based on accurate reproduction strategies. For this reason, measurements and observations should be made often, particularly during the mating season, once it has been established. Various variables should be tested for including water temperature, oxygen levels, and the presence of toxic pollutants that may drain off from the development. Although these fish are subject to great risk, current populations seem to be stable; therefore efforts should be focused in learning about the species at this time. If populations start to show a decline, timber removal and construction may need to be halted in order to prevent disastrous siltation. Even if no danger is current observed, extra pressure should be put on the companies in charge of the Walden ridge timber mining and development in order to ensure proper practices to prevent pollution and reduce impact on the land and nearby streams. So, currently C. saylori is not in prominent danger, but if left unmanaged, could quickly become driven to extirpation or extinction.

Phoxinus saylori (syn. Chrosomus saylori) is a rare species of fish in the carp family known by the common name laurel dace. It is endemic to Tennessee in the United States, where it occurs in six streams in the Tennessee River drainage. It was federally listed as an endangered species of the United States on August 9, 2011, a ruling which will take effect on September 8, 2011.^[10]

This minnow is 45.7 millimeters long on average. It is olive green to tan in color with a silvery white underside. It has two black stripes on each side. During the breeding season the fish changes color, developing bright red coloration on the lower parts. Part of the dorsal fin becomes red, as do the lips. The stripes become a deeper black and there are more black areas on the head and breast. The cheeks and the area between the black stripes become gold. Most of the fins turn yellow. Females and males both change colors, but the male's colors are more intense. Otherwise, female and male can be told apart by the shape of the pectoral fins.^[11]

The fish is named for an ichthyologist, Charles F. Saylor, who was one of the first to collect it. Its common name refers to mountain laurel (Kalmia spp.), which is a common plant next to the streams where it lives.^[11]

This fish occurs on the Walden Ridge of the Cumberland Plateau in Tennessee. It is found in six streams: the Soddy, Horn, Cupp, Young's, Moccasin, and Bumbee Creeks, all of which drain into larger rivers that eventually feed the Tennessee River.^[10] It is believed to be extirpated from Laurel Creek, the only other stream where it was known to occur.^[11]

This fish is threatened by increased sedimentation in its habitat, which occurs because surrounding hillsides have been logged, leading to erosion. This accumulation of silt makes the fish's spawning areas unsuitable. Such activities can cause erosion, which increases siltation, impeding spawning efforts. Eggs can be suffocated by sediment settling into the rocky streambeds. In order to protect this species, preventative measures must be taken that include enacting more stringent agricultural policies on farming and mining runoff and preventing further human actions that might weaken the streams’ health and integrity. Maintaining riverside, or riparian, vegetation is also essential in anchoring the soil of the creek banks to prevent further siltation. Without taking the time to study and protect this species, it could quickly be lost forever. There are only a few populations, and the destruction of one or more of them would have a large impact on the fish's total numbers, bringing it closer to extinction.^[10][11]

References

1. Luther, E. T. 2009. Walden Ridge and Sequatchie Valley. The Tennessee Encyclopedia of History and Culture. Ver. 2.0. 18 November 2011. http://tennesseeencyclopedia.net/entry.php?rec=1449

2. Howes, G. J. 1985. A revised synonymy of the minnow genus Phoxinus Rafinesque, 1820 (Teleostei: Cyprinidae) with comments on its relationships and distribution. Bull. Br. Mus. Nat. Hist. (Zool.) 48:57– 74.

3. Phoxinus saylori- Laurel Dace. Conservation Fisheries Inc. 2011. 18 November 2011. <http://conservationfisheries.org/index.php/species/all-species/phoxinus-saylori-laurel-dace/>

4. Phoxinus saylori, Laurel Dace. Fishbase. 2010. 18 November 2011. http://www.fishbase.org/summary/Phoxinus-saylori.html

5. Raney, E. C. 1947. Nocomis nests used by other breeding cyprinid fishes in Virginia. Zoologica 32:125– 132.

6. Species Profile for Laurel Dace (Phoxinus saylori). U.S. Fish and Wildlife Service. 21 November 2011. <http://www.fws.gov/ecos/ajax/speciesProfile/profile/speciesProfile.action?spcode=E0AR>

7. Skelton, C. E. 2001. New dace of the genus Phoxinus (Cyprinidae: Cypriniformes) from the Tennessee River Drainage, Tennessee. Copeia 2001:118–128.

8. Starnes, W. C., and R. E. Jenkins. 1988. A new cyprinid fish of the genus Phoxinus (Pisces: Cypriniformes) from the Tennessee River drainage with comments on relationships and biogeography. Proc. Biol. Soc. Wash. 101:517–529.

9. Starnes, L. B., and W. C. Starnes. 1981. Biology of the blackside dace Phoxinus cumberlandensis. Am. Midl. Nat. 106:360–371.

10. Strange, R. M. and R. L. Mayden. 2009. Phylogenetic relationships and revised taxonomy for North American cyprinids currently assigned to Phoxinus (Actinopterygii: Cyprinidae). Copeia, : 496–504.

External links

• Phoxinus saylori. FishBase.