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Bathyraja richardsoni

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA CHONDRICHTHYES RAJIFORMES ARHYNCHOBATIDAE

Scientific Name: Bathyraja richardsoni
Species Authority: (Garrick, 1961)
Common Name(s):
English Richardson’s Skate, Deepsea Skate, Richardson’s Ray
French Raie De Richardson
Spanish Raya De Richardson
Synonym(s):
Raja richardsoni Garrick, 1961

Assessment Information [top]

Red List Category & Criteria: Least Concern ver 3.1
Year Published: 2007
Date Assessed: 2007-03-01
Assessor(s): Kulka, D.W., Orlov, A. & Barker, A.
Reviewer(s): Dulvy, N.K. & Valenti, S.V. (Shark Red List Authority)
Justification:
Bathyraja richardsoni is likely to be cosmopolitan. Sporadic, deep records from various parts of its range indicate that this species is widespread and it is suspected that the distribution is much wider than records indicate. Their deep bathydemersal distribution (most records exceed 1,000 m) places them outside of the range of most human threats, including deepwater fishing. Given the species' wide depth and geographic range, the majority of the population is thought to exist outside the range of deepwater fisheries and this species is considered Least Concern. Deepwater fisheries should be monitored and managed.

Geographic Range [top]

Range Description: Likely cosmopolitan. In the northwest Atlantic, records of this species occur from the southern Labrador Shelf, Canada to the mid-Atlantic Bight. The first northwest Atlantic records, taken on survey longlines between 1965 and 1967, comprised 18 mature specimens taken at depths between 1,370 and 2,360 m (Scott and Scott 1988). These constituted the only northwest Atlantic records until 2003 when a mature male and a mature female were collected from the slope fishery north of the Grand Banks (D. Kulka pers. obs. 2006). In the northeast Atlantic, it has been recorded from the northwestern Bay of Biscay to northern Ireland (Stehmann and Merrett 2001). Recently this skate was found off the Azores and in the Mid-Atlantic ridge area (A. Orlov pers. obs. 2006). In the southwest Pacific, there is only a single record known (holotype) off New Zealand (Garrick 1961).
Countries:
Native:
Canada; France; Portugal (Azores); United States (Massachusetts, New Jersey)
FAO Marine Fishing Areas:
Native:
Atlantic – northeast; Atlantic – northwest; Pacific – southwest
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Population size and parameters are unknown.
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: This marine species is bathydemersal, with records in deep water (1,219 to 2,992 m) on continental slopes, submarine rises and deepsea plains (Ayling and Cox 1982) with a diet consisting primarily of teleost fishes and crustaceans (Templeman 1973).

B. richardsoni reaches a maximum size of 174 cm total length (TL) (Tempelman 1973) and size at birth is 18.2 to 24.5 cm TL. The species is oviparous with egg capsules having a length measurement of 34 to 45.2 cm (including egg horns) or 20 to 20.8 cm (excluding egg horns), and a maximum width of 11.2 to 12 cm (Stehmann and Merrett 2001).
Systems: Marine

Threats [top]

Major Threat(s): The main human threat to this species is deepwater fisheries. However, much of the range of this species occurs well beyond most deepwater fisheries.

Potentially a bycatch in deepwater longline and gillnet fisheries in areas of the North Atlantic, where deepwater fishing activities have increased 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 to 1,200 m), and 400 m off Nova Scotia (D. Kulka pers. comm). About 10 to 20% of the Northwest Atlantic slope is fished annually (D. Kulka pers. comm). However this species is rarely captured, and the majority of its range is considered outside the range of fishing pressure.

This species' wide depth distribution, relatively wide geographic range and that they are rarely caught at depths less than 800 m (D. Kulka pers. comm.) may offer refuge from fishing pressure. Deepwater fisheries should be monitored and managed.

Conservation Actions [top]

Conservation Actions: No regulations exist for this species. To prevent this species from moving out of the Least Concern category deepwater fisheries operating close to its range should be monitored.

Citation: Kulka, D.W., Orlov, A. & Barker, A. 2007. Bathyraja richardsoni. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 28 November 2014.
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