Dipturus innominatus 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Chondrichthyes Rajiformes Rajidae

Scientific Name: Dipturus innominatus (Garrick & Paul, 1974)
Common Name(s):
English Smooth Skate
Raja innominata Garrick & Paul, 1974
Taxonomic Source(s): Eschmeyer, W.N., Fricke, R. and Van der Laan, R. (eds.). 2018. Catalog of Fishes: genera, species, references. Updated 29 March 2018. Available at:

Assessment Information [top]

Red List Category & Criteria: Near Threatened ver 3.1
Year Published: 2003
Date Assessed: 2003-04-30
Needs updating
Assessor(s): Francis, M.P. (SSG Australia & Oceania Regional Workshop, March 2003)
Reviewer(s): Fowler, S. & Kyne, P.M. (Shark Red List Authority)
Widespread throughout New Zealand, and frequent in shelf waters around South Island. Long life span (> 24 years) and late age at maturity (females 13 years) result in a long generation period and indicate low productivity. Trawl survey biomass indices in the main abundance area of east coast South Island show no trends, though there is evidence of inter-annual variation in catchability that may invalidate the time series. Expected to be introduced to the Quota Management System in October 2003. On this basis alone, the species would be assessed as Least Concern. However, its low productivity and vulnerability to capture before reaching maturity means that the species could quickly move towards a threatened category if management measures are inadequate to regulate fishing mortality at a sustainable level. It is therefore considered to be Near Threatened until the QMS is operational and CPUE data indicate that the population is stable.

Geographic Range [top]

Range Description:Ranges throughout coastal waters of North and South islands, Stewart Is - Snares Islands Shelf, and Chatham Rise, plus scattered records from the Campbell Plateau. Depth range from the shore to about 1,200 m but rare deeper than 800 m.
Countries occurrence:
New Zealand (North Is., South Is.)
FAO Marine Fishing Areas:
Pacific – southwest
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Trawl survey biomass indices in the main abundance area of east coast South Island show no trends, though there is evidence of inter-annual variation in catchability that may invalidate the time series.
Current Population Trend:Stable
Additional data:

Habitat and Ecology [top]

Habitat and Ecology:Soft bottom habitats on the continental shelf and upper slope; most abundant on the mid-outer continental shelf. They feed on benthic invertebrates and small fish. Females lay pairs of eggs in leathery cases on the seabed. Embryos hatch at about 10-15 cm pelvic length (PL) (snout tip to posterior margin of pelvic fins). Males mature at 93 cm PL and 8 years of age, and females at 112 cm PL and 13 years. Females grow larger and probably older than males, and reach at least 158 cm PL and 24 years of age.

Threats [top]

Major Threat(s): Commercial catch of around 1,000 tonnes per year in bottom trawl and bottom longline fisheries (exact quantities are unknown because rough [Dipturus nasutus] and smooth skates are frequently lumped in landings statistics). Skates are not targeted, but are retained when caught.

Conservation Actions [top]

Conservation Actions: A total competitive quota of 900 tonnes for all skates and rays was introduced in 1991-92 for the east coast of South Island, but landings have exceeded the quota every year since it was introduced. The Ministry of Fisheries proposes to introduce smooth skate into the Quota Management System in October 2003.

Classifications [top]

10. Marine Oceanic -> 10.1. Marine Oceanic - Epipelagic (0-200m)

In-Place Research, Monitoring and Planning
In-Place Land/Water Protection and Management
In-Place Species Management
In-Place Education
5. Biological resource use -> 5.4. Fishing & harvesting aquatic resources -> 5.4.4. Unintentional effects: (large scale) [harvest]
♦ timing:Ongoing    

1. Research -> 1.2. Population size, distribution & trends
3. Monitoring -> 3.1. Population trends

Bibliography [top]

Anderson, O.F., Bagley, N.W., Hurst, R.J., Francis, M.P., Clark, M.R. and McMillan, P.J. 1998. Atlas of New Zealand fish and squid distributions from research bottom trawls. NIWA Technical Report 42. NIWA, Wellington. 303 pp.

Francis, M.P. 1997. A summary of biology and commercial landings and a stock assessment of rough and smooth skates (Raja nasuta and R. innominata). New Zealand Fisheries Assessment Research Document 97/5.

Francis, M.P. 1998. New Zealand shark fisheries: development, size and management. Marine and Freshwater Research 49: 579-591.

Francis, M.P., Ó Maolagáin, C. and Stevens, D. 2001. Age, growth, and sexual maturity of two New Zealand endemic skates, Dipturus nasutus and D. innominatus. New Zealand Journal of Marine and Freshwater Research 35: 831-842.

IUCN. 2003. 2003 IUCN Red List of Threatened Species. Downloaded on 18 November 2003.

Shark Specialist Group. For more information, see the Specialist Group website.

Citation: Francis, M.P. (SSG Australia & Oceania Regional Workshop, March 2003). 2003. Dipturus innominatus. The IUCN Red List of Threatened Species 2003: e.T41799A10549817. . Downloaded on 19 September 2018.
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