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Raja inornata

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Taxonomy [top]

Kingdom Phylum Class Order Family
ANIMALIA CHORDATA CHONDRICHTHYES RAJIFORMES RAJIDAE

Scientific Name: Raja inornata
Species Authority: Jordan & Gilbert, 1881
Common Name(s):
English California Skate
Taxonomic Notes: This skate is often misidentified with other hardnose skates from the northeast and eastern central Pacific.

Assessment Information [top]

Red List Category & Criteria: Data Deficient ver 3.1
Year Published: 2009
Date Assessed: 2008-12-01
Assessor(s): Robinson, H.J., Ebert, D.A. & Cailliet, G.M.
Reviewer(s): Valenti, S.V., Kulka, D.W. & Fowler, S.L. (Shark Red List Authority)
Justification:
The California Skate (Raja inornata) is found at depths of 17-671 m on the continental shelf of the northeast and eastern central Pacific. It occurs from the Straits of Juan de Fuca, southwards to central Baja California, Mexico, with a disjunct population in the Gulf of California. Very little is known about this skate and no detailed life history studies have been conducted. It is often misidentified with other hardnose skates from the northeast and eastern central Pacific, precluding the collection of species-specific catch data. The species is a utilized bycatch in commercial longline and trawl fisheries and is one of three commercially important skate species in California. Total annual landings for unspecified skate species in California declined from 577 t and 633 t in 2000 and 2001 to between 82-125 t from 2002-2005. The proportion of this species in the catches is not known. Effort in the California trawl fishery has recently reduced and a network of proposed marine protected areas is being instigated (2007) in response to declining fish stocks. Fishing pressure on this species has therefore likely reduced. However, no data are available to determine past population trends in this species it is assessed as Data Deficient at the present time.

Geographic Range [top]

Range Description: Northeast and eastern central Pacific: known from the Straits of Juan de Fuca off British Colombia, Canada and Washington, USA, as well as Oregon, California, and central Baja California, Mexico. Also, from the Gulf of California (Benson et al. 2001, Miller and Lea 1972, McEachran and Notobartolo di Sciara 1995).
Countries:
Native:
Canada (British Columbia); Mexico (Baja California, Baja California Sur, Sonora); United States (California, Oregon, Washington)
FAO Marine Fishing Areas:
Native:
Pacific – eastern central; Pacific – northeast
Range Map: Click here to open the map viewer and explore range.

Population [top]

Population: Nothing is known on its population structure or status. Skates are generally not identified to species level and are often misidentified, precluding the collection of accurate species-specific catch data. However, extensive surveys and collation of catch statistics for northeast and eastern central Pacific waters (including California, Oregon, and Washington) have been conducted (D. Ebert pers. obs. 2007).
Population Trend: Unknown

Habitat and Ecology [top]

Habitat and Ecology: Found on soft bottoms at depths of 17-671 m (Ebert 2003, Miller and Lea 1972). Males are reported to mature at about 47 cm total length (TL) and females at about 52 cm TL (Ebert 2003). The maximum reported size is 76 cm TL (Jordan and Gilbert 1881). Size at birth is 15-23 cm TL (Ebert 2003). They are reported to feed on small benthic invertebrates including polychaete worms and shrimp (Ebert 2003).
Systems: Marine

Use and Trade [top]

Use and Trade: Utilized as a bycatch species.

Threats [top]

Major Threat(s): Usually a utilized bycatch in commercial longline and trawl fisheries (Martin and Zorzi 1993). One of three commercially important skate species in California and it is marketed for human consumption (Rodel and Ripley 1950, Matin and Zorzi 1993). Total annual commercial landings data into California for the grouped category "Skate, unspecified" indicate that landings declined from ~577 t and ~633 t in 2000 and 2001 to ~82 t in 2002. Landings then fluctuated between ~12 t and ~95 t from 2003-2005 (California Department of Fish and Game 2007). However, the proportion of this species in the catches is not known. Given that this species appears to occur on the continental shelf it is likely not as affected as other species may have been, such as the longnose skate, Raja rhina.

The trawl fishery in California has been slowly closing and a network of marine protected areas (MPAs) in Californian waters is being instigated, in response to declines in rockfish populations which overlap with the habitat of this species (D. Ebert pers. obs. 2007). Most trawlers now have to work in deeper water and mostly in central and northern California. Southern California is largely closed at this time (D. Ebert pers. obs. 2007). Effort in the trawl fishery in California waters has therefore reduced and not nearly as many are being taken as once might have been (D. Ebert pers. obs. 2007).

Conservation Actions [top]

Conservation Actions: Measures in place

California's Marine Life Protection Act, effective from 21st September 2007, establishes a Central Coast Region, composed of 29 marine protected areas (MPAs) off the state. (See: http://www.dfg.ca.gov/mlpa/newsroom_083107.asp for further details). The 29 sites within the Central Coast MPA series represent approximately 204 square miles (roughly 18 percent) of state waters in the Central Coast Study Region. The implementation of these MPAs in currently ongoing.

Southern California waters are largely closed to trawl fishing at this time (D. Ebert pes. obs. 2007).

Citation: Robinson, H.J., Ebert, D.A. & Cailliet, G.M. 2009. Raja inornata. The IUCN Red List of Threatened Species. Version 2014.3. <www.iucnredlist.org>. Downloaded on 28 November 2014.
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