|Scientific Name:||Cephaloscyllium umbratile Jordan & Fowler, 1903|
|Taxonomic Notes:||The species was formerly synonymized (Compagno 1984) with the similar Cephaloscyllium isabellum (Compagno et al. 2005). Records apparently include at least two mostly sympatric species, the large C. umbratile and a smaller undescribed species (Compagno et al. 2005).|
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Assessor(s):||Iglésias, S., Tanaka, S. & Nakaya, K.|
|Reviewer(s):||Valenti, S.V. & Fowler, S.L. (Shark Red List Authority)|
The Japanese Swellshark (Cephaloscyllium umbratile) is a locally abundant catshark, endemic to the northwest Pacific. Found from Honshu, Japan, south to Taiwan, Province of China, and possibly to New Guinea. Little is known of the biology but this is a relatively small oviparous species and may therefore be more productive than larger live-bearing sharks. Although no data are available to assess population trends, the species is apparently still abundant in areas that are heavily fished by trawlers. Small scyliorhinid species have proven resilient to population decline, even where they are heavily fished (for example the Smallspotted Catshark (Scyliorhinus canicula) in the northeast Atlantic). However, records of Japanese Swellshark apparently include C. umbratile and a smaller undescribed sympatric species. The two species may be confused and C. umbratile is a larger catshark, and may be more vulnerable to depletion. Therefore this species is assessed as Data Deficient until further information is available on its life-history, catches in fisheries and population trends.
|Range Description:||Northwest and western central Pacific: from Honshu, Japan, south to Korea and the Yellow Sea, China and Taiwan, possibly to New Guinea (K. Nakaya and S. Tanaka pers. obs. 2007, Compagno et al. 2005).|
Native:Japan (Hokkaido, Honshu, Kyushu, Nansei-shoto, Ogasawara-shoto, Shikoku); Taiwan, Province of China
|FAO Marine Fishing Areas:|
Pacific – northwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||No specific information is available on the population, but the species is apparently locally abundant.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||A bottom-dwelling catshark of the continental shelves, found offshore at depths of 90-200 m (Taniuchi 1988). The reproduction and diet of this species was studied in Choshi and Suruga Bay, Japan (Taniuchi 1988, Horie and Tanaka 2002). In Suruga Bay the data collected from 1,377 specimens (992 and 385 specimens from western and eastern of the bay respectively) indicates that the minimum size of adults was 82.4 cm total length (TL) for males and 90.6 cm TL for females. Size at birth was about 18 cm TL (Horie and Tanaka 2002). Reproduction is oviparous. In Choshi, the study of 356 specimens suggests size at maturity is attained at 86-88 cm TL for males and at 92-94 cm TL for females (Taniuchi 1988, Horie and Tanaka 2002). All males measuring greater than 96 cm TL and females over 104 cm were mature (Taniuchi 1988, Horie and Tanaka 2002). The largest observed male in Choshi was 114 cm TL and the largest female was 114.5 cm TL (Taniuchi 1988). The species does not have a well-defined reproductive season (Taniuchi 1988).|
In Suruga Bay, the species preyed on a wide variety of marine organisms such as Gnathostomata, Cephalopoda and Crustacea. The diet of the young varies in different locations. In Choshi, the food items of the species consisted of at least 71 prey species, principally fishes. Pacific mackerel and Japanese sardine were the dominant prey. Ten species of Chondrichthyan fishes were also important in their diet (Taniuchi 1988).
|Major Threat(s):||This species is a retained bycatch of commercial bottom trawl and longline fisheries off Japan (Taniuchi 1988). It is captured incidentally by shrimp bottom trawlers using nets with mesh ~2-4 cm in diameter, so both adults and juveniles are retained by the trawl (S. Iglésias pers. obs. 2007). The species is sometimes observed on the Tachi and Nan Fang Hao fish markets, Taiwan. It is apparently still abundant in areas that are heavily fished by trawlers (S. Iglésias, S. Tanaka and K. Nakaya obs. 2007).|
None currently in place.
Further research is needed on the taxonomy of this species, as well as species-specific information on abundance, capture in fisheries and population trends.
|Citation:||Iglésias, S., Tanaka, S. & Nakaya, K. 2009. Cephaloscyllium umbratile. The IUCN Red List of Threatened Species 2009: e.T161724A5488954.Downloaded on 22 February 2018.|
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