|Scientific Name:||Hydrolagus colliei|
|Species Authority:||(Lay & Bennett, 1839)|
Chimaera colliei Lay & Bennett, 1839
Chimaera media Garman, 1911
|Taxonomic Source(s):||Eschmeyer, W.N. and Fricke, R. (eds). 2015. Catalog of Fishes: genera, species, references. Updated 1 October 2015. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (Accessed: 1 October 2015).|
|Taxonomic Notes:||Fowler (1910) stated that Chimaera neglecta Ogilby, 1888 is probably a synonym of H. colliei, but it is more likely to be a synonym of H. novaezealandiae (Didier and Rosenberger 2002).|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Barnett, L.A.K., Ebert, D.A. & Dagit, D.D.|
|Reviewer(s):||Kemper, J. & Walovich, K.A.|
|Facilitator/Compiler(s):||Lawson, J., Walls, R.H.L. & Dulvy, N.K.|
Spotted Ratfish (Hydrolagus colliei) is widespread along the western coast of North America from southern Alaska to Baja and the Gulf of California, and has been recorded in the Pacific waters of Costa Rica. This species that appears to be abundant throughout the core of its range from British Columbia, Canada to Puget Sound, Washington, USA. One of the best-studied of all chimaeroid fishes, life history studies indicate that this species is very fecund, producing 20-29 eggs per year. This species is not targeted by fisheries, but it is taken as bycatch in commercial trawl and longline fisheries and rarely retained. Fisheries-independent surveys of Spotted Ratfish along the west coast of the United States suggest that this species is stable or increasing throughout this area. Given the broad distribution of this species, generally high abundance, recent increases in population size, and evidence to suggest that the population can recover from substantial bycatch, this species is assessed as Least Concern.
|Previously published Red List assessments:||
Spotted Ratfish is widespread along the western coast of North America from southern Alaska (Wilimovsky 1954) to Baja and the Gulf of California (Ebert 2003), being most abundant in the inshore waters of British Columbia, Canada and Puget Sound, Washington, USA (Palsson 2002, Palsson et al. 2004), along with the coastal waters off northern and southern California, USA (Barnett et al. 2012). It is also present in Central America off the Pacific coast of Costa Rica (Angulo et al. 2014).
Native:Canada (British Columbia); Costa Rica; Mexico (Baja California, Baja California Sur); United States (Alaska, California, Oregon, Washington)
|FAO Marine Fishing Areas:||
Pacific – northeast; Pacific – eastern central
|Lower depth limit (metres):||913|
|Range Map:||Click here to open the map viewer and explore range.|
Fishery-independent data from the northeast Pacific indicates Spotted Ratfish comprises a large proportion of the vertebrate biomass in the demersal community of the shelf and upper slope (Keller et al. 2006). Fishery-independent catch per unit effort (CPUE) data were collected from Washington, Oregon and California by the Alaska Fisheries Science Centre (AFSC) triennial trawl surveys from 1977 to 2004, and the Northwest Fisheries Science Centre (NWFSC) West Coast Groundfish surveys from 2003-2006. From 1977 to 1995 CPUE was stable, and from 1995 to 2006 CPUE increased (Barnett et al. 2012). Increases in Spotted Ratfish populations were particularly pronounced from 1998 onwards along the northern region of the US west coast shelf and upper slope, and increases were not observed in the southern shelf and upper slope, perhaps because of climate (a strong El Niño cycle) and differences in fishing pressure (Barnett et al. 2012).
|Current Population Trend:||Increasing|
|Habitat and Ecology:||Spotted Ratfish are most common over soft-bottom or cobble habitats and around rocky reefs (Ebert 2003). They have been observed as shallow as the sea surface in some inshore waters (Dean 1906), but generally occur at depths to 913 m on the open coast (Alverson et al. 1964) and are most abundant on the outer shelf and upper continental slope (Barnett et al. 2012). The species also occurs into the intertidal zone in the northern parts of its range (Dean 1906). Their bathymetric distribution is shallower at higher latitudes (Dean 1906, Barnett et al. 2012). Although their movements are not understood in detail, they do seem to display vertical and alongshore migrations within inlets protected from the open coast (Mathews 1975, Quinn et al. 1980, Andrews and Quinn 2012). Populations appear to segregate by sex and size (Mathews 1975, Quinn et al. 1980, Barnett et al. 2012), with dense aggregations of juveniles and egg cases observed around offshore banks near the shelf break (Barnett et al. 2012).
This species is oviparous with peak reproductive period from late spring to fall (Barnett et al. 2009a). Egg cases are laid in pairs at a rate of approximately once per 17-19 days and extrapolating this over the 6-8 month reproductive season provides an estimated annual fecundity of approximately 20-29 eggs/year (Barnett et al. 2009a). The incubation period within the egg case is about 12 months, with newborns emerging at about 14 cm total length (TL) (Didier and Rosenberger 2002). Size at maturity for the population on the U.S. west coast is 19 cm snout-vent length (SVL) for females and 15-16 cm SVL for males. Maximum sizes for the population on the U.S. west coast are 63 cm TL for females and 50 cm TL for males. Both size at maturity and maximum size increase with latitude, and historical estimates of maximum size of the species were much greater than reported here (97 cm TL; Miller and Lea 1972). It seems unlikely that the species can be reliably aged (Johnson and Horton 1972, Barnett et al. 2009b). Indeed no robust estimates of generation length are available for any Hydrolagus spp.
|Use and Trade:||This species is not utilized.|
There is no directed fishery for Spotted Ratfish. This species is reported a bycatch in groundfish bottom trawl gear, and discard mortality as bycatch may impact this species. Although reported landings are minimal, it is likely that the number of ratfish discarded at sea is quite large, given their abundance and vulnerability to trawl gear.
The regional fishery management council for the northeast Pacific has set overfishing limits and acceptable biological catch limits, but they have proposed that the stock simply be monitored instead of actively managed (PFMC 2014).
|Citation:||Barnett, L.A.K., Ebert, D.A. & Dagit, D.D. 2015. Hydrolagus colliei. The IUCN Red List of Threatened Species 2015: e.T60191A80678052. . Downloaded on 30 November 2015.|
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