|Scientific Name:||Harriotta raleighana Goode & Bean, 1895|
|Taxonomic Source(s):||Eschmeyer, W.N., Fricke, R. and Van der Laan, R. (eds). 2016. Catalog of Fishes: genera, species, references. Updated 2 May 2016. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (Accessed: 2 May 2016).|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Dagit, D.D., Walls, R.H.L. & Buscher, E.|
|Reviewer(s):||Bigman, J.S. & Kyne, P.M.|
|Facilitator/Compiler(s):||Kyne, P.M. & Walls, R.H.L.|
The Narrownose Chimaera (Harriotta raleighana) appears to be the only chimaeroid with a widespread, alebit patchy, circumglobal distribution. It occurs in deepwater on continental slopes at depths of 350 to 2,600 m in the Atlantic, Pacific, and Indian Oceans. The species appears to be somewhat common in the northern Atlantic, Northwest Pacific and Southwest Pacific, however, very little is known about its biology. This chimaera is caught in deepwater research trawls and as bycatch in deepwater commercial trawls, but only as a negligible component of bycatch. Expansion of deepwater trawl fisheries could pose a potential threat to the population and its habitats in future, but at present deepwater fishery effort is decreasing in some areas such as Europe with no signs of re-expansion in the near future. At present this species appears to be widespread geographically and bathymetrically and relatively abundant with no immediate threats to the population and is thus assessed as Least Concern.
|Previously published Red List assessments:|
|Range Description:||The Narrownose Chimaera appears to be widespread yet patchily distributed across the world, although it is not widely recorded in the Indian Ocean at present, with the largest numbers recorded from the western Pacific and northern Atlantic. It is caught occasionally in southern Australian waters, from New South Wales to Western Australia, including Tasmania and Tasman Sea seamounts and ridges, as well as on the continental slopes of New Zealand (Last and Stevens 2009). In the Northeast Atlantic, this species occurs off southeast Greenland, Iceland, and the Rockall Trough, to the United Kingdom, and possibly to the Bay of Biscay, but this is not confirmed (Ebert and Stehmann 2013). It has been recorded near the Canary Islands by Bigelow and Schroeder (1953), however these records may in fact refer to the Smallspine Spookfish (H. haeckeli). This species is the only chimaeroid that may be circumglobal in its distribution.|
Native:Australia (New South Wales, South Australia, Tasmania, Victoria, Western Australia); Brazil; Canada (Nova Scotia); China; France; Greenland; Iceland; Japan; Mexico; New Zealand; South Africa (Western Cape); Spain (Canary Is.); United Kingdom; United States (California, Connecticut, Delaware, Maine, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Rhode Island, South Carolina, Virginia)
|FAO Marine Fishing Areas:|
Atlantic – southwest; Atlantic – eastern central; Atlantic – northeast; Atlantic – northwest; Atlantic – southeast; Indian Ocean – western; Indian Ocean – eastern; Pacific – southwest; Pacific – northwest; Pacific – eastern central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||This species appears to be fairly abundant where it is known to occur, although nothing is known about population structure or trend. Molecular evidence may support regional subpopulations but as yet there is no evidence for this. The population is inferred to be stable based on the lack of overlap between this species and fisheries or other human threats.|
|Current Population Trend:||Stable|
|Habitat and Ecology:|
This deepwater species primarily occurs over continental slopes at depths of 350−2,600 m (Last and Stevens 2009, Ebert and Stehmann 2013). It has been observed with remote operated vehicles over soft mud and gravelly bottom substrates and sometimes in association with other deepwater chimaeroids (Ebert and Stehmann 2013). Similar to many other chimaeroids, adults and juveniles may occupy different habitats and an ontogenetic shift in depth occurs with large individuals occurring deeper than smaller individuals (Ebert and Stehmann 2013).
Females grow larger than males. The maximum recorded size is 70 cm precaudal length; size at maturity for males is ~25−30 cm body length (BDL) and for females, it is ~30 cm BDL; size at birth is ~10−13 cm precaudal length (Ebert and Stehmann 2013). Little is known about the spawning and reproduction of this egg-laying species, other than it has a small egg case around 16 cm in length (Ebert and Stehmann 2013).
|Use and Trade:||There is no known use or trade of this species.|
The Narrownose Chimaera is not known to be targeted in any commercial fishery but is caught as bycatch in commercial deepwater bottom trawls. This species was a negligible component of the South Tasman Rise Trawl Fishery (STRF) bycatch, with an estimated catch of 0.31 tonnes in 545 tows between November 1998 and September 2000 (< 0.1 of total catch) of which 8% was retained (Anderson and Clark 2003). The STRF targeted Orange Roughy (Hoplostethus atlanticus) and other deepwater teleost species south of Tasmania as a straddling stock between Australia and New Zealand, however it was closed in 2007 due to stock depletion so fishing pressure in this area should no longer be an issue (Patterson and Bath 2015). In the European region, deepwater fishery effort has been decreasing for about a decade, with no current signs of re-expansion (Dransfeld et al. 2013, STECF 2014).
This species appears to be relatively common in deepwater survey trawls. Any increase in deepwater trawl fisheries could pose a potential threat to habitats and populations in the future and monitoring would be required.
|Conservation Actions:||No species-specific management or conservation measures are in place. Data from specimens collected incidentally would be helpful in understanding population structure and life history of this species. Additionally, deepwater fishery effort should be monitored throughout its range, and in the event of fishery expansion, this assessment should be revisited.|
|Citation:||Dagit, D.D., Walls, R.H.L. & Buscher, E. 2016. Harriotta raleighana. The IUCN Red List of Threatened Species 2016: e.T60140A3088899.Downloaded on 23 October 2017.|
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