Rajella bathyphila 

Scope: Global
Language: English

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Taxonomy [top]

Kingdom Phylum Class Order Family
Animalia Chordata Chondrichthyes Rajiformes Rajidae

Scientific Name: Rajella bathyphila (Holt & Byrne, 1908)
Regional Assessments:
Common Name(s):
English Deepwater Skate
Raja bathyphila Holt & Byrne, 1908

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2009
Date Assessed: 2008-12-01
Assessor(s): Stehmann, M.
Reviewer(s): Kulka, D.W. & Valenti, S.V. (Shark Red List Authority)
A deepwater skate occurring in the Northeast and Northwest Atlantic on deeper continental slopes and probably abyssal plains, mainly at depths greater than 1,400 m. Rajella bathyphila is occasionally landed as bycatch of deepwater fisheries, but its deepwater range places the majority of the population outside the range of current fishing pressure. In the absence of potential threats and data to suggest declines, the species is assessed as Least Concern. If deepwater fisheries expand to greater depths within this species range’ in future, this assessment should be revisited. Monitoring of catches is important given that deepwater skates generally have limiting life-history characteristics that can make them vulnerable to rapid depletion when heavily fished.

Geographic Range [top]

Range Description:Northeast Atlantic: Denmark-Strait, off south western Iceland, including Reykjanes Ridge, Rockall Trough along Ireland, in the northern region of the Bay of Biscay and south to off Rio de Oro in Western Sahara. It may occur throughout the area in very deep water and on the Mid-Atlantic Ridge (Stehmann 1978, Stehmann 1995).

Northwest Atlantic: occurs off the northeastern coast of the USA and Canadian slope, north of 45°N and to the Flemish Cap (Stehmann 1995).
Countries occurrence:
Canada; Greenland; Iceland; Ireland; United States; Western Sahara
FAO Marine Fishing Areas:
Atlantic – northeast; Atlantic – northwest; Atlantic – eastern central
Additional data:
Range Map:Click here to open the map viewer and explore range.

Population [top]

Population:Moderately rare (McEachran and Stehmann 1977, Stehmann and Bürkel 1984, Stehmann 1978, Stehmann 1995).
Current Population Trend:Unknown
Additional data:
Population severely fragmented:No

Habitat and Ecology [top]

Habitat and Ecology:Rajella bathyphila is found on deeper continental slopes and probably abyssal plains, mainly deeper than 1,400 m (Stehmann and Bürkel 1984). Like other skates, it is oviparous with females producing around 40 egg capsules each per year. Size at birth is 11.5 cm (Stehmann 1978). Adults reach sexual maturity at about 65 cm total length (TL) for both males and females, with fully mature females of 83 and 93 cm TL recorded off Canada (D. Kulka pers. comm. 2006). The maximum recorded size for R. bathyphila is 93 cm TL (Stehmann 1978).

Threats [top]

Major Threat(s): This species is occasionally caught as bycatch in deep-water fisheries locally and seasonally, and is mostly discarded. This species’ deepwater distribution (most records exceed 1,000 m) places them outside of the range of many fisheries.

Areas of the northeast Atlantic, for example the Rockall Trough have been subject to a fairly rapid increase in deepwater fishing activities since the 1990s with overall concern for the sustainability of deepwater fish stocks (Gordon 2003). In the northwest Atlantic, deepest fishing sets occur at 1,500 m off Newfoundland (most deep fishing in the range of 700–1,200 m), and 400 m off Nova Scotia (D. Kulka pers. comm.). About 10–20% of the northwest Atlantic slope is fished annually (D. Kulka pers. comm.).

Conservation Actions [top]

Conservation Actions: None in place.

Recommended: Expanding deepwater fisheries and bycatch levels should be monitored to ensure that this potentially vulnerable species is not detrimentally affected.

Citation: Stehmann, M. 2009. Rajella bathyphila. The IUCN Red List of Threatened Species 2009: e.T161345A5403027. . Downloaded on 15 October 2018.
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