Spotted killifish

Spotted killifish
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Cyprinodontiformes
Family: Aplocheilidae
Genus: Nothobranchius
Species: N. orthonotus
Binomial name
Nothobranchius orthonotus

The Spotted killifish, also called the Nothobranchius orthonotus, is a small, short lived species of fish that is in the family Aplocheilidae. These fish are native to many isolated freshwater pools located in the savannah depressions of east Africa, specifically Malawi, Mozambique, Zimbabwe, and South Africa.[2] Since these species of fish are used to ephemeral waters, the killifish eggs can survive long periods of dehydration. The word killifish likely comes from the Dutch kil for kill (small stream).[3]

Diet

The Nothobranchius orthonotus consumes both aquatic invertebrates and vertebrates. The diet consists mainly of juvenile lungfish (Protopterus annectens) and larval amphibia. In addition to this, the Nothobranchius orthonotus also consumes a relatively high proportion of Odonata, Coleoptera and Ephemeroptera larvae. Diets such as these may be deemed as profitable for the trade-offs in item size and ease of catching.[4]

Life Cycle and Reproduction

The Nothobranchius orthonotus, along of the genus Nothobranchius, are adapted to annual desiccation of their habitat. Fishes hatch at the start of each rainy season, and continue to grow very quickly. Within a matter of a few weeks, these fish reach sexual maturity, and reproduce daily, with females laying up to 50 eggs each day. From here, the eggs are spawned into a layer of rock or soil beneath the surface of the ground, and remain there after the pool has dried up. Even with a dry environment, the embryos are able to exist in developmental suspension until the starts of the next wet season.[5]

Characteristics

Fish with the genus Nothobranchius show a striking level of sexual dichomatism, where the males portray bright colors, and the females are dull. The adult Nothobranchius orthonotus is one of the largest of its genus, and can grow up to 10 cm in length.[6]

Habitat and Ecology

The Nothobranchius orthonotus is native to isolated freshwater pools located in the savannah depressions of east Africa, specifically Malawi, Mozambique, Zimbabwe, and South Africa. This species was found to share these pools with N. furzeri, N. kadleci and N.rachovii, all subsets of the same genus. The natural environments inhabited can range from non-vegetated and shallow with cloudy water, all the way to densely overgrown pools, that are fairly deep and have clear water. This species may also be present in swamps intermittently connected to floodplains. Given the lifecycle of the Nothobranchius orthonotus, it has adapted to varying dry and wet weather conditions that persist in this part of the world. However, due to recent anti-malarial and tsetse fly spraying programs, the populations of Nothobranchius orthonotus are becoming threatened. Though this species is threatened, it is at lower risk, and not yet in need of acts of conservation given that the threats are localized.[7]

See also

References

  1. ↑ Bills, R.; Engelbrecht, J.; Kazembe, J.; Marshall, B.; Tweddle, D. (2010). "Nothobranchius orthonotus". IUCN Red List of Threatened Species. IUCN. 2010: e.T61182A12438885. Retrieved 30 July 2016.
  2. ↑ Bills, R; Engelbrecht, J; Kazembe, J; Marshall, B; Tweddle, D. "Nothobranchius orthonotus". The IUCN Red List of Threatened Species. Retrieved 26 February 2018.
  3. ↑ van der Sijs, Nicoline (January 1, 2010). "Cookies, Coleslaw and Stoops: The Influence of Dutch on the North American Language". Amsterdam University Press: 198. ISBN 9789089641243.
  4. ↑ Polacik, M; Reichard, M (June 29, 2010). "Diet overlap among three sympatric African annual killifish species Nothobranchius spp. from Mozambique". Journal of Fish Biology. 77 (3): 754–768. doi:10.1111/j.1095-8649.2010.02717.x.
  5. ↑ Reichard, M; Polacik, M; Sedlacek, O (January 19, 2009). "Distribution, colour polymorphism and habitat use of the African killifish Nothobranchius furzeri, the vertebrate with the shortest life span". Journal of Fish Biology. 74 (1): 198–212. doi:10.1111/j.1095-8649.2008.02129.x.
  6. ↑ Reichard, M; Polacik, M; Sedlacek, O (January 19, 2009). "Distribution, colour polymorphism and habitat use of the African killifish Nothobranchius furzeri, the vertebrate with the shortest life span". Journal of Fish Biology. 74 (1): 198–212. doi:10.1111/j.1095-8649.2008.02129.x.
  7. ↑ Luna, Susan. "Nothobranchius orthonotus". Fish Base.
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