|Scientific Name:||Eptatretus polytrema (Girard, 1855)|
Bdellostoma polytrema Girard, 1855
|Taxonomic Notes:||Many authors reported the occurrence of polibranchiated hagfishes in Chilean waters under the species name polytrema. However, these citations pertain to unrecognizable species in that neither count had useful proportions or color notes provided. A complete list of names and references of these unassignable records was provided by Wisner and McMillan (1988), which also contains citations under the species name dombey (Gastrobranche dombey La Cepède, 1798) or dombeyi (Gastrobranchus dombeyi Shaw, 1804), an unrecognizable myxinid from Chile.|
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Reviewer(s):||Polidoro, B., Knapp, L. & Carpenter, K.E.|
This species is only known from a few museum specimens off the coast of Chile, and has not been recorded since 1988. There are no current threats known to the species, as current trawling activities have ceased. However, given is shallow depth range, it is unusual that no specimens have been recorded in over 20 years, indicating that historical trawling activities may have significantly reduced the population through bycatch incidences and habitat destruction. It is listed as Data Deficient. More information is needed on this species distribution, population, biology, life history and impact of past trawling activities.
|Range Description:||This species is found off the coast of Chile, from Bahía Inglesa to Talcahuano (about 27° to 37°S). One specimen reported from the O’Higgins seamount group, eastern Juan Fernandez Islands, at 33°27'S, 77°52'W.|
|FAO Marine Fishing Areas:|
Pacific – southeast
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The population of this species is known from only a few museum specimens. Last records date back to 1988 and no specimens have been reported since then.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||This species is usually living on muddy and rocky bottoms from shallow coastal waters to upper slope and seamounts at depths from 10-350 m. Of the 19 specimens examined by Wisner and McMillan (1988), 13 were mature females with developing eggs. Four females (385-447 mm total length (TL)) had from 24-40 well developed eggs ranging from 16-27.5 mm in length and about 4.5-7 mm in diameter. One 289 mm female was considered immature.|
The copulatory organ is absent for this species. The gonads of hagfishes are situated in the peritoneal cavity. The ovary is found in the anterior portion of the gonad, and the testis is found in the posterior part. The animal becomes female if the cranial part of the gonad develops or male if the caudal part undergoes differentiation. If none develops, then the animal becomes sterile. If both anterior and posterior parts develop, then the animal becomes a functional hermaphrodite. However, hermaphroditism being characterised as functional needs to be validated by more reproduction studies (Patzner 1998).
|Major Threat(s):||There are no known direct threats to this species and bottom trawling activities along the continental slope have almost ceased, likely due to a collapse of the shallow water fisheries. Mid-water fishing continues but this is not a threat to the species (Roberto Melendez pers. comm.).|
|Conservation Actions:||There are no conservation measures in place, but more research is needed on species' biology, population size, distribution and the historical impact of bottom trawling activities along the continental shelf.|
Bahamonde, N.N. and Pequeño, G.R. 1975. Peces de Chile. Lista sistematica. Publicación Ocasional - Museo Nacional de Historia Natural 21: 3-20.
Girard, C.F. 1855. Abstract of a report to Lieut. Jas. M. Gilliss, U.S.N., upon the fishes collected during the U. S. N. Astronomical Expedition to Chile. Proceedings of the Academy of Natural Sciences of Philadelphia 7: 197-199.
IUCN. 2011. IUCN Red List of Threatened Species (ver. 2011.1). Available at: http://www.iucnredlist.org. (Accessed: 30 June 2017).
Patzner, R.A. 1998. Gonads and reproduction in hagfishes. In: J.M. Jørgensen, J.P. Lomholt, R.E. Weber, and H. Malte (eds), The biology of hagfishes, pp. 378-395. Chapman & Hall, London.
Pequeño, G. 1989. Peces de Chile. Lista sistematica revisada y comentada. Revista de Biologia Marina, Valparaiso 24(2): 1-132.
Wisner, R.L. and McMillan, C.B. 1988. A new species of hagfish, genus Eptatretus (Cyclostomata, Myxinidae), from the Pacific Ocean near Valparaiso, Chile, with new data on E. bischoffii and E. polytrema. Transactions of the San Diego Society of Natural History 21(14): 227-244.
|Citation:||Mincarone, M.M. 2011. Eptatretus polytrema. The IUCN Red List of Threatened Species 2011: e.T196040A8996877.Downloaded on 20 September 2017.|
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