The greenthroat darter (Etheostoma lepidum) is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is found in Colorado, Guadalupe and Nueces River drainages in Texas; and in Pecos River system in New Mexico.[2]

Greenthroat darter
In Texas
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Family: Percidae
Genus: Etheostoma
Species:
E. lepidum
Binomial name
Etheostoma lepidum
Baird & Girard, 1853
From the Comal River, Texas

Habitat Associations

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Macrohabitat: Basically a spring-run species.[3] Mesohabitat: Scarce or absent from very eurythermal locations.[3] Occurs in a variety of non-turbid stream habitats with substrates from bedrock to silt covered (Platania 1980). A typical riffle species occurring over gravel and rubble, especially when aquatic vegetation is present. It also lives in spring areas, sometimes in cool vegetated pools.[4] Largest populations occur in vegetated rocky riffles.[5][6][7][8] Species benthic after hatching.[6][9]

Biology

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Spawning season

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October or November through May, with populations in stenothermal environments having a longer spawning season than those in more eurythermal environments.[6][3] In the Colorado River, Texas, spawning occurs November – May;[10] in the South Concho River, Texas, spawning occurs October – May.[11] Hubbs (1985)[3] reported marked drop in reproductive activity when water temperature was raised from 20 to 23 °C.

Spawning habitat

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Eggs laid on vegetation,[12] or on the underside of rocks.[6]

Fecundity

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In the South Concho River, TX, eggs averaged 1.3 mm in diameter, and increased in number with female size; average number of eggs in females examined was 74, with a range of about 15–200.[11] In aquaria, spawning was observed at approximately 15–25 °C; over a 63-day period, a pair of Etheostoma lepidum laid 13 batches of eggs; numbers of eggs laid ranged from 47 to 109, totaling 1,115.[12] Optimal temperature for egg production apparently 20–23 °C; a female held at this temperature range was observed to produce eggs, in the laboratory environment, over a period of at least 251 days.[6] Egg incubation success is low above 24 degrees C.[13] At 28 degrees C, eggs hatch in 4–5 days, and hatch in about 40 days at 9 °C. Hubbs (1985)[3] noted that no difference in egg production could be correlated with daylength.

References

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  1. ^ NatureServe (2014). "Etheostoma lepidum". IUCN Red List of Threatened Species. 2014: e.T202500A2745352. doi:10.2305/IUCN.UK.2014-3.RLTS.T202500A2745352.en. Retrieved 19 November 2021.
  2. ^ "Etheostoma lepidum, Greenthroat darter".
  3. ^ a b c d e Hubbs, C. 1985. Darter reproductive seasons. Copeia 1985(1):56-68.
  4. ^ Kuehne, R.A., and R.W. Barbour. 1983. The American Darters. The University Press of Kentucky. Lexington. 177 pp.
  5. ^ Strawn, K. 1955. A method of breeding and raising three Texas darters. Part I. Aquarium Journal 26:408-41
  6. ^ a b c d e Hubbs, C., and K. Strawn. 1957. The effects of light and temperature on the fecundity of the greenthroat darter, Etheostoma lepidum. Ecology 38:596-602.
  7. ^ Hubbs, C., R.A. Kuehne, and J.C. Ball. 1953. The fishes of the upper Guadalupe River. Texas Journal of Science 5(2):216-244.
  8. ^ Hubbs, C., and A.A. Echelle. 1972. Endangered non-game fishes of the upper Rio Grande basin pp. 147–167. In: Rare and endangered wildlife of Southwestern United States. New Mexico Game and Fish Dept., Santa Fe.
  9. ^ Paine, M.D. 1984. Ecological and evolutionary consequences of early ontogenies of darter (Etheostomatini). pp. 21–30. In: Lindquist, D.G., and L.M. Page (eds.), Environmental Biology of Darters. Dr W Junk Publishers, The Hague.
  10. ^ Developmental temperature tolerance of four etheostomatine fishes occurring in Texas. Copeia 1961:195-198.
  11. ^ a b Hubbs, C., M.M. Stevenson, and A.E. Peden. 1968. Fecundity and egg size in two central Texas darter populations. Southwestern Naturalist 13:301-323
  12. ^ a b Strawn, K. 1956. A method of breeding and raising three Texas darters. Part II. Aquarium Journal 27(1):11-32.
  13. ^ Hubbs, C., A.E. Peden, and M.M. Stevenson. 1969. The developmental rate of the greenthroat darter, Etheostoma lepidum. Amer. Midl. Nat. 81:182-188.