The bluemask darter (''Etheostoma akatulo'') is a species of freshwater
ray-finned fish
Actinopterygii (; ), members of which are known as ray-finned fishes, is a class of bony fish. They comprise over 50% of living vertebrate species.
The ray-finned fishes are so called because their fins are webs of skin supported by bony or hor ...
, a darter from the
subfamily
In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...
Etheostomatinae
Etheosomatidae is a species rich subfamily of freshwater ray-finned fish, the members of which are commonly known as the darters. The subfamily is part of the family Percidae which also includes the perches, ruffes and pikeperches. The family i ...
, part of the
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Percidae
The Percidae are a family of ray-finned fish, part of the order Perciformes, which are found in fresh and brackish waters of the Northern Hemisphere. The majority are Nearctic, but there are also Palearctic species. The family contains more than ...
, which also contains the
perch
Perch is a common name for fish of the genus ''Perca'', freshwater gamefish belonging to the family Percidae. The perch, of which three species occur in different geographical areas, lend their name to a large order of vertebrates: the Percif ...
es,
ruffes and
pikeperches. It is
endemic
Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...
to the eastern
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
. It is a federally listed
endangered species
An endangered species is a species that is very likely to become extinct in the near future, either worldwide or in a particular political jurisdiction. Endangered species may be at risk due to factors such as habitat loss, poaching and inv ...
of the United States. This fish was not formally described until 2009,
[Layman, S. R. and R. L. Mayden. (2009)]
A new species of the darter subgenus ''Doration'' (Percidae: ''Etheostoma'') from the Caney Fork River System, Tennessee.
''Copeia'': February 2009, Vol. 2009, No. 1, pp. 157-170. but it was added to the US Endangered Species List in 1993.
[USFWS]
Determination of Endangered Status for the Relict Darter and Bluemask (=Jewel) Darter.
''Federal Register'' December 27, 1993. During breeding, the male has bright blue patches on its head and other areas.
[''Etheostoma akatulo''.]
FishBase. This fish is found only in the
Caney Fork River
The Caney Fork River is a river that flows through central Tennessee in the United States, draining a substantial portion of the southwestern Cumberland Plateau and southeastern Highland Rim regions. It is a major tributary of the Cumberland River ...
system, a tributary of the
Cumberland River
The Cumberland River is a major waterway of the Southern United States. The U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map, accessed June 8, 2011 river drains almost of southern Kentucky and ...
in Tennessee.
[ The species name ''akatulo'' comes from the ]Cherokee
The Cherokee (; chr, ᎠᏂᏴᏫᏯᎢ, translit=Aniyvwiyaʔi or Anigiduwagi, or chr, ᏣᎳᎩ, links=no, translit=Tsalagi) are one of the indigenous peoples of the Southeastern Woodlands of the United States. Prior to the 18th century, t ...
for "mask
A mask is an object normally worn on the face, typically for protection, disguise, performance, or entertainment and often they have been employed for rituals and rights. Masks have been used since antiquity for both ceremonial and practic ...
", referring to the solid blue coloration on the lower face of the fish.[
]
Anatomy and appearance
The species differs from other species of the subgenus Doration by having fully scaled cheeks, complete lateral line, breeding males with bright blue pigment completely covering the lower face, and breeding males with soft dorsal and anal fins lacking orange and blue pigment.[
]
Geographic distribution
''Etheostoma akatulo'' is known from five small rivers and large creeks of the upper Caney Fork River system, Tennessee, including Collins River, Rocky River, Calfkiller River, Cane Creek, and upper Caney Fork River. ''Etheostoma akatulo'' is most abundant and widely distributed in Collins River, where it occurs in a 37-km reach between Shellsford, Warren Co., and Tennessee Highway 56, 1.2 km east of Mt. Olive, Grundy Co. In Rocky River, the species inhabits only a 4.3-km reach from Tennessee Highway 30 upstream to Laurelburg Road ford, Van Buren Co., including a 1.7-km reach that alternates between backwater and free-flowing conditions as Great Falls Reservoir fluctuates between maximum (244 m) and minimum (240 m) pool elevations.[Layman Steven R.; Simons Andrew M.; Wood Robert M.(1993). Status of the dirty darter, Etheostoma olivaceum and bluemask darter, Etheostoma (Doration) sp., with notes on fishes of the Caney Fork River System, Tennessee. Journal of the Tennessee Academy of Science Volume: 68 Issue: 2 Pages: 65-70.] In Cane Creek, recent collections are from the lower 200 m of free-flowing waters in Van Buren Co. In upper Caney Fork River, the species has been collected in an intermittent reach located only 1.8 river km upstream of reservoir maximum pool in White Co. ''Etheostoma akatulo'' is restricted in distribution to the Caney Fork River system in free-flowing streams upstream of Great Falls. All four extant populations apparently are isolated from one another by the impounded waters of Great Falls Reservoir.[
]
Ecology
Not much is known about the ecology of ''Etheostoma akatulo''. All darters, as their name implies, dart about on the bottoms of streams and eat small crustaceans and insects.[http://www.fws.gov/cookeville/docs/bluemask.htm
] ''Etheostoma akatulo'' occurs in slow to moderate current over sand and fine gravel at depths of 10–50 cm, typically just downstream of riffles, in runs, or along margins of pools.[ During spawning ''Etheostoma akatulo'' males and females have been seen occupying different microhabitats. Substrate dominated by gravel were occupied by lone males and spawning pairs, whereas most lone females were found over a sand-dominant substrate.][Simmons Jeffrey W.; Layzer James B.(2004). Spawning behavior and habitat of the endangered bluemask darter, Etheostoma (Doration) sp. Copeia Volume: 2004 Issue: 2 Pages: 412-417.] After the spawning period, Bluemask Darters move to sandy substrates in low-velocity areas of intermediate depth.[Layzer James B.; Brady Tony R.(2003). Summer microhabitat of the endangered bluemask darter Etheostoma (Doration) sp. Journal of the Tennessee Academy of Science Volume: 78 Issue: 2 Pages: 55-57.]
Life history
The life cycle of ''Etheostoma akatulo'' has been compared to that of '' Etheostoma stigmaeum''.[Simmons, J W; Layzer, J B.(2003). Reproductive ecology of the endangered bluemask darter, Etheostoma ]oration
Public speaking, also called oratory or oration, has traditionally meant the act of speaking face to face to a live audience. Today it includes any form of speaking (formally and informally) to an audience, including pre-recorded speech deliver ...
sp. Southeastern Biology, 50(2): p. 160 ''Etheostoma akatulo'', before it was formally described, was once considered a subspecies of ''Etheostoma stigmaeum''. ''E. stigmaeum'' is known to lay its eggs in gravelly areas and after they have been laid, it covers them with the gravel. ''Etheostoma akatulo'' is believed to demonstrate the same egg laying behavior. ''E. akatulo'' can live to be 39 months old. They show the highest amount of growth during the first year of life but do not reach sexual maturity until year two.[Simmons Jeffrey W.; Layzer James B.; Smith David D.(2008). Age-class Structure and Variability of Two Populations of the Bluemask Darter Etheostoma (Doration) sp. American Midland Naturalist Volume: 160 Issue: 2 Pages: 300-309.]
Management
''Etheostoma akatulo'' was listed as a federally endangered species in 1993.[ Existing and potential threats to continued survival of the species include habitat destruction from gravel dredging, which has already eliminated habitat once occupied by the species in Collins River; pesticides in runoff or groundwater from plant nurseries; siltation from gravel mining, agricultural runoff, or land-disturbing activities; and ]acid mine drainage
Acid mine drainage, acid and metalliferous drainage (AMD), or acid rock drainage (ARD) is the outflow of acidic water from metal mines or coal mines.
Acid rock drainage occurs naturally within some environments as part of the rock weathering ...
from headwater streams.[ The most significant factor contributing to the bluemask darter's decline was likely the building of the Great Falls Dam.]
References
{{Taxonbar, from=Q3758017
Etheostoma
Fish described in 2009
Natural history of Tennessee
ESA endangered species