Orestias (fish)

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Orestias
Orestias cuvieri
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cyprinodontiformes
Family: Cyprinodontidae
Genus: Orestias
Valenciennes, 1839
Type species
Orestias cuvieri
Valenciennes, 1846[1]

Orestias is a genus of

ventral fin, although this is shared by a few other pupfish.[6] Despite their moderate to small size, they are important to local fisheries and a few species are farmed.[7]

Several species are locally and colloquially known as carache. The name of the genus is a reference to Orestes, a Greek mythological character who Valenciennes described as the "nymph of the mountains".[8]

Range and habitat

Four Orestias (possibly O. luteus) and two Trichomycterus catfish caught in Lake Titicaca, the center of Orestias richness

Orestias is restricted to freshwater habitats at an altitude of 2,800–4,600 m (9,200–15,100 ft) in the

macrophytes, some at the bottom in water too deep for macrophytes (deeper than 10 m or 33 ft), and some pelagically in the open water.[10] Orestias species found elsewhere than Lake Titicaca often have very small ranges.[2]

Behavior

Relatively little is known about the behavior of Orestias.[4]

They feed on small crustaceans (such as

niche differentiation, including some that mainly feed on zooplanktonic organisms, two (O. albus and O. cuvieri) that are particularly willing to take other fish, primarily smaller Orestias (fish eggs are regularly consumed by a wider range of species), several that mainly feed on small bottom- or plant-living organisms, and some that are generalists that will feed on a wide range of things,[3][4][10][12] sometimes varying depending on season.[11]

Females tend to grow larger than males. Although generally rather dull-coloured, breeding males may become partially yellow or orange. The eggs, up to a few hundred, are placed in shallow water among vegetation. Orestias appear to reach maturity when around one year old.[4]

Conservation and relationship to humans

Many species of the genus became rare in recent decades due to predation by, and competition with

Argentinian silverside), pollution, overfishing and other human activities in their habitats.[13][14] In the 1960s, an expedition to Lake Titicaca led by Jacques Cousteau reported seeing many dead Orestias and when studied they were found to be infected by a disease introduced with the trout.[15]

The two largest species in the genus, the

Lake Chungará.[18][19]

Despite their moderate to small size, some species are important to local fisheries, but they are overfished, there are few regulations and limited enforcement of the rules that do exist.[14][16] In Lake Titicaca, the moderately sized O. agassizii and O. luteus (complexes) represent more than 90% of the total catches of native fish species,[7] but others like the small open-water ispi (O. forgeti and O. ispi) are also frequently caught.[20] The natives have now been greatly surpassed by fisheries for the non-native introduced trout and Argentinian silverside.[14] Because of pollution, studies have revealed levels of metals in Orestias of Lake Titicaca that exceed the internationally recommended safety thresholds for human consumption.[21] O. agassizii and O. luteus are also farmed and spawned in captivity; both to supply the food market and for release to support their vulnerable wild populations.[7][22]

Species and taxonomy

Three Orestias species showing some of the variations in shape in this genus

There are currently 45 recognized species in this genus,

standard length of c. 17 cm (6.5 in),[21] but otherwise they are quite different. Despite this, hybrids between them are known.[7]

Agassizii species complex

Some species restricted to the Lake Titicaca basin (which includes the inflowing rivers and connected smaller lakes like Arapa, Lagunillas and Saracocha), and some restricted to other lakes, rivers and springs elsewhere in the Andean highlands. O. agassizii (often spelled agassii instead[23]) is the only member of the genus found both in the Lake Titicaca basin and elsewhere.[6]

Cuvieri species complex

All restricted to the Lake Titicaca basin.[6]

Gilsoni species complex

All restricted to the Lake Titicaca basin.[6]

Mulleri species complex

All restricted to the Lake Titicaca basin.[6]

References

  1. ^ Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Orestias". Catalog of Fishes. California Academy of Sciences. Retrieved 20 October 2019.
  2. ^ a b c d Vila, Morales, Scott, Poulin, Veliz, Harrod and Mendez (2013). Phylogenetic and phylogeographic analysis of the genus Orestias (Teleostei: Cyprinodontidae) in the southern Chilean Altiplano: the relevance of ancient and recent divergence processes in speciation. Journal of Fish Biology 82, 927–943.
  3. ^
    doi:10.1111/j.1095-8649.2008.02140.x
    .
  4. ^
    doi:10.1080/14634980701351395
    .
  5. ^ a b c Froese, Rainer and Pauly, Daniel, eds. (2012). Species of Orestias in FishBase. August 2012 version.
  6. ^ a b c d e f g h i Parenti, Lynne R. (1984): A taxonomic revision of the Andean Killifish Genus Orestias (Cyprinodontiformes, Cyprinodontidae). Bulletin of the American Museum of Natural History 178: 107-214. PDF fulltext
  7. ^ a b c d Esquer-Garrigos, Y.; B. Hugueny; C. Ibañez; C. Zepita; K. Koerner; J. Lambourdière; A. Couloux; P. Gaubert (2015). "Detecting natural hybridization between two vulnerable Andean pupfishes (Orestias agassizii and O. luteus) representative of the Altiplano endemic fisheries". Conservation Genetics. 16 (3): 717–727.
  8. ^ Christopher Scharpf; Kenneth J. Lazara (26 April 2019). "Order CYPRINODONTIFORMES: Families PANTANODONTIDAE, CYPRINODONTIDAE, PROFUNDULIDAE, GOODEIDAE, FUNDULIDAE and FLUVIPHYLACIDAE". The ETYFish Project Fish Name Etymology Database. Christopher Scharpf and Kenneth J. Lazara. Retrieved 20 October 2019.
  9. ^ a b Chocano Arévalo, L. (2005). "Las zonas altoandinas peruanas y su ictiofauna endémica". Revista Digital Universitaria. 6 (8): 1–13.
  10. ^
    ISBN 0-7923-1663-0
    .
  11. ^ a b Loayza, E. (2019). "Seasonal and depth variations in diet composition and dietary overlap between three native killifish of an emblematic tropical-mountain lake: Lake Titicaca (Bolivia)". Retrieved 18 January 2020.
  12. ^
    doi:10.1111/jfb.12529
    .
  13. ^
    ISBN 978-99974-41-84-3
    .
  14. ^ a b c d e Bloudoff-Indelicato, M. (9 December 2015). "What Are North American Trout Doing in Lake Titicaca?". Smithsonian Magazine. Retrieved 18 January 2020.
  15. ^ Cousteau, J.; A. Landsburg (24 April 1969). "The Legend of Lake Titicaca". The Undersea World of Jacques Cousteau. Episode 7.
  16. ^ a b "Los peces nativos del Titicaca, en peligro". Fundación Nuestra Mar. 3 March 2010. Retrieved 18 January 2020.
  17. doi:10.3354/esr00785
    .
  18. doi:10.1111/bij.12704
    .
  19. ^ Froese, Rainer; Pauly, Daniel (eds.) (2020). "Orestias chungarensis" in FishBase. January 2020 version.
  20. ^ McKittrick, E. (2018). "Saving the Scrotum Frog". Earth Island Journal. Retrieved 27 January 2020.
  21. ^
    doi:10.1016/j.scitotenv.2014.03.134
    .
  22. ^ UNDP (5 March 2019). "Prosper under the sun: Faced with the ever-increasing global demand for renewable energy, two Andean communities in Peru use solar energy to develop sustainable businesses". americalatinagenera.org. Retrieved 18 January 2020.
  23. ^ Eschmeyer, William N.; Fricke, Ron & van der Laan, Richard (eds.). "Species related to Orestias agassii". Catalog of Fishes. California Academy of Sciences. Retrieved 18 January 2020.
  24. ^ Vila, I., Scott, S., Mendez, M.A., Valenzuela, F., Iturra, P. & Poulin, E. (2012): Orestias gloriae, a new species of cyprinodontid fish from saltpan spring of the southern high Andes (Teleostei: Cyprinodontidae). Ichthyological Exploration of Freshwaters, 22 (4) [2011]: 345-353.
  • Lüssen, Arne (2003): Zur Systematik, Phylogenie und Biogeographie chilenischer Arten der Gattung Orestias VALENCIENNES, 1839. Doctoral thesis, University of Hamburg, Germany. [in German] PDF fulltext
  • Villwock, W. (1964): Vermeintliche Artbastarde in der Gattung Orestias (Pisces, Cyprinodontidae). Mitteilungen aus dem Hamburgischen Zoologischen Museum und Institut, Kosswig-Festschrift: 285-291. [Article in German]
  • Villwock, W. (1972): Gefahren für die endemische Fischfauna durch Einbürgerungsversuche und Akklimatisation von Fremdfischen am Beispiel des Titicacas-Sees (Peru/Bolivien) und des Lanao-Sees (Mindanao/Philippinen). Verhandlungen des Internationalen Vereins für Limnologie 18: 1227-1234. [Article in German]
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