Bathyraja spinosissima

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

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Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	CHONDRICHTHYES	RAJIFORMES	ARHYNCHOBATIDAE

Scientific Name:

Bathyraja spinosissima

Species Authority:

(Beebe & Tee-Van, 1941)

Common Name/s:

English

–

Pacific White Skate

Synonym/s:

Psammobatis spinosissima Beebe & Tee-Van, 1941

Assessment Information [top]

Red List Category & Criteria:	Least Concern ver 3.1
Year Published:	2009
Assessor/s:	Ebert, D.A. & Orlov, A.
Reviewer/s:	Valenti, S.V., Kyne, P.M. & Kulka, D.W. (Shark Red List Authority)
Justification: Pacific White Skate (Bathyraja spinosissima) is a large, rarely encountered deepwater skate, known only from a few scattered specimens caught in trawl and longline surveys in the eastern Pacific and Sea of Okhotsk, northwest Pacific. It is one of the deepest living skate species, occurring to nearly 3,000 m depth, beyond the range of most trawl operations. ROV footage off of central California suggests that this species lives on rocky substrate, which also precludes it being caught by trawl fisheries. Given that this species’ deep habitat is mostly outside the range of current fisheries, the rocky substrate on which it is found is unsuitable for trawling and no population declines have been observed, it is assessed as Least Concern. The designation of the Davidson Seamount as a Marine Protected Area will also offer this species protection in the future. However, any fisheries extending further into its range should be monitored, as any bycatch may be of concern due to the large body size and likely intrinsic vulnerability of this species to population depletion.

Geographic Range [top]

Range Description:	Northwest and eastern Pacific: Pacific White Skate (Bathyraja spinosissima) has a patchy distribution from northern South America to off Port Waldport, Oregon, USA, and the Sea of Okhotsk (Ebert 2003, Ebert, pers. obs. 2007 Dolganov 1999, Fedorov et al. 2003). The distribution map for the Pacific White Skate in McEachran and Notarbartolo-di-Sciara (1995) depicts the species occurring in the Galápagos Islands (apparently also followed by Ebert (2003)). This appears to be an error, and the species has not been recorded around the Galápagos Islands (J.D. McEachran pers. comm. 2007). This species was described by Beebe and Tee-Van (1941) from a location ‘sixty miles south of Cocos Islands’ (04°50′N, 87°W), and it is this record that may have been confused for the Galápagos Islands.
Countries:	Native: Costa Rica (Cocos I., Costa Rica (main island) - Presence Uncertain); Russian Federation (Kamchatka - Presence Uncertain, Khabarovsk - Presence Uncertain, Sakhalin - Presence Uncertain); United States (California - Presence Uncertain, Oregon) Presence uncertain: Colombia; Ecuador; El Salvador; Guatemala; Mexico; Nicaragua
FAO Marine Fishing Areas:	Native: Pacific – southeast; Pacific – northeast; Pacific – northwest; Pacific – eastern central
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	In the waters of the western coast on the USA, Pacific White Skate is known mostly from photographs from ROV surveys and perhaps only about 4–6 specimens have been captured (Ebert pers. obs. 2007). In the Sea of Okhotsk, this species appears to be uncommon according to bottom trawl survey data. It was caught in 2.3% of 257 hauls in a deepwater survey in 1999 in a depth range down to 2,000 m (Dudnik and Dolganov 1992).
Population Trend:	Unknown

Population:

In the waters of the western coast on the USA, Pacific White Skate is known mostly from photographs from ROV surveys and perhaps only about 4–6 specimens have been captured (Ebert pers. obs. 2007). In the Sea of Okhotsk, this species appears to be uncommon according to bottom trawl survey data. It was caught in 2.3% of 257 hauls in a deepwater survey in 1999 in a depth range down to 2,000 m (Dudnik and Dolganov 1992).

Population Trend:

Unknown

Habitat and Ecology [top]

Habitat and Ecology:	This is one of the deepest living skate species occurring from 800-2,906m deep on the western US coast continental slope (Ebert 2003). In the Sea of Okhotsk, the depth range is 1,250–2,025 m (Dudnik and Dolganov 1992). ROV photgraphs often show this species swimming 1–3 m off the bottom over rocky substrates (D. Ebert pers. obs. 2007). Attains a maximum length of at least 203 cm (Dolganov and Tuponogov 1999). Like other skates, reproduction is oviparous (Ebert 2003). An egg case measured 9.2 cm length and 6.65 cm width (Ebert and Davis 2007). Size at birth is reported at ~26 cm TL (Ebert 2003).
Systems:	Marine

Habitat and Ecology:

This is one of the deepest living skate species occurring from 800-2,906m deep on the western US coast continental slope (Ebert 2003). In the Sea of Okhotsk, the depth range is 1,250–2,025 m (Dudnik and Dolganov 1992). ROV photgraphs often show this species swimming 1–3 m off the bottom over rocky substrates (D. Ebert pers. obs. 2007).

Attains a maximum length of at least 203 cm (Dolganov and Tuponogov 1999). Like other skates, reproduction is oviparous (Ebert 2003). An egg case measured 9.2 cm length and 6.65 cm width (Ebert and Davis 2007). Size at birth is reported at ~26 cm TL (Ebert 2003).

Systems:

Marine

Threats [top]

Major Threat(s):	Pacific White Skate is known only from a few scattered records throughout its range occurring to nearly 3,000 m which is beyond the depth range of most trawl operations. Videotape footage of this species from 1,875 m deep off central California suggest that it lives on rocky substrate that also precludes its being caught by trawl fishing operations (D. Ebert pers obs. 2007).

Major Threat(s):

Pacific White Skate is known only from a few scattered records throughout its range occurring to nearly 3,000 m which is beyond the depth range of most trawl operations. Videotape footage of this species from 1,875 m deep off central California suggest that it lives on rocky substrate that also precludes its being caught by trawl fishing operations (D. Ebert pers obs. 2007).

Conservation Actions [top]

Conservation Actions:	The Davidson Seamount, located 75 km off the central Californian Coast (within the known range of this species) has been proposed as a Marine Protected area (D. Ebert pers. obs. 2007). At present, the species occurs mainly beyond the depth of fishing operations on rocky untrawlable substrate. It is unlikely then, that deep bottom trawl fisheries will develop in the area, however the situation should be monitored. Like other large deepwater skates, this species is probably intrinsically vulnerable to population depletion and therefore any bycatch would be of concern. Further specimens are required for research on the species’ biology and life-history characteristics.

Conservation Actions:

The Davidson Seamount, located 75 km off the central Californian Coast (within the known range of this species) has been proposed as a Marine Protected area (D. Ebert pers. obs. 2007).

At present, the species occurs mainly beyond the depth of fishing operations on rocky untrawlable substrate. It is unlikely then, that deep bottom trawl fisheries will develop in the area, however the situation should be monitored. Like other large deepwater skates, this species is probably intrinsically vulnerable to population depletion and therefore any bycatch would be of concern. Further specimens are required for research on the species’ biology and life-history characteristics.

Citation:	Ebert, D.A. & Orlov, A. 2009. Bathyraja spinosissima. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 24 May 2012.
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