User:Kaanoi3/Eleotris sandwicensis

Eleotris sandwicensis

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Eleotris sandwicensis, the Sandwich Island sleeper, Hawaiian sleeper, or oʻopu, is a species of fish in the family Eleotridae. It is endemic to the Hawaiian Islands and is the only endemic eleotrid in Hawaii. It can be found in marine, fresh, and brackish waters around the coast. Due to this capability of migrating between different marine environments, they are amphidromous.[3]  This fish is described as mottled black coloration with seven fins and can reach a length of 33 cm (13 inches). Due to the lack of the pelvic fins they are not very good climbers. In the Hawaiian language, the fish is also known as oʻopu, ʻoau, ʻowau, and hiʻu kole.

The distribution of E. sandwicensis is limited, as this species does not have the ability to travel upstream of steep waterfalls.[5]This is due to their lack of pelvic fins.[5]

Habitat

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Lower reaches of streams and estuarine regions, wetland areas. Most common on O‘ahu. ‘O‘opu ‘akupa populations are stable in both altered and unaltered streams.[5]

Reproduction

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Spawning happens in the freshwater and the nests are made in small crevices at the bottom of the stream. Eggs are then hatched 24 hours post birth. After their release they will flow into the sea where the offspring will spend a few months there before returning upstream. This is dependent on the tides and currents to bring them inshore. Egg lay hatching takes place in the spring during the night.

Growth and diet

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Although E. sandwicensis is a predator that will eat any fish that can fit in it's mouth, it's favorite is the hïhïwai or Neritina granosa. They are fresh snails that graze on algae on hard surfaces in freshwater.

Ecology and living environment influencing growth

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‘O‘opu akupa are difficult to keep in aquariums because they are very aggressive and will eat anything smaller than itself.

Conservation

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Eleotris sandwicensis is being threatened due to the nutrients, pollution and chemicals that are in the water sources; the streams and ponds. [5] It is frequently attacked by the North American leech Myzobdella lugubris. [7]

Cultural significance

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This species was valued for eating by native Hawaiians because of its tasty white meat. Today, the Eleotris sandwicensis or ‘o‘opu akupa are used as baitfish for pāpio, another native Hawaiian fish.

References

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  1. NatureServe (2013). "Eleotris sandwicensis". IUCN Red List of Threatened Species. 2013: e.T7134A3137134. doi:10.2305/IUCN.UK.2013-1.RLTS.T7134A3137134.en. Retrieved 17 November 2021.[1]
  2. Maie, Takashi; Furtek, Steffanie; Schoenfuss, Heiko L.; Blob, Richard W. (February 2014). "Feeding performance of the Hawaiian sleeper, Eleotris sandwicensis (Gobioidei: Eleotridae): correlations between predatory functional modulation and selection pressures on prey: Feeding Performance of a Piscivorous Predator". Biological Journal of the Linnean Society. 111 (2): 359–374. doi:10.1111/bij.12214.[2]
  3. Sim, Tara (December 2006). "Reproductive Biology of Eleotris Sandwicensis, a Hawaiian Stream Gobioid Fish" (PDF).[3]
  4. Froese, Rainer; Pauly, Daniel (eds.) (2013). "Eleotris sandwicensis" in FishBase. April 2013 version.[4]
  5. Alda, F.; Gagne, R. B.; Walter, R. P.; Hogan, J. D.; Moody, K. N.; Zink, F.; McIntyre, P. B.; Gilliam, J. F.; Blum, M. J. (2016-07-21). "Colonization and demographic expansion of freshwater fauna across the Hawaiian archipelago". Journal of Evolutionary Biology. 29 (10): 2054–2069. doi:10.1111/jeb.12929. ISSN 1010-061X. PMID 27369460. S2CID 31136761.[5]
  6. Brasher AM. 1997. Habitat use by fish (‘o‘opu), snails (hihiwai), shrimp (‘opae) and prawns in two streams on the island of Moloka`i. Technical Report. Honolulu HI: Cooperative National Park Resources Studies Unit University of Hawaii at Manoa. Report no 116. 92 pp.[6]
  7. Kinzie RA III. 1990. Species profiles: life histories and environmental requirements of coastal vertebrates and invertebrates, Pacific Ocean region; Report 3, Amphidromous macrofauna of island streams. Technical Report EL-89-10. Vicksburg, MS: US Army Engineer Waterways Experiment Station.[7]
  8. "ʻoʻopu akupa 1" by Pelika Andrade is licensed under CC BY-SA 4.0. To view a copy of this license, visit https://creativecommons.org/licenses/by-sa/4.0/?ref=openverse.%5B7] [8]