|Scientific Name:||Squalus brevirostris|
|Species Authority:||Tanaka, 1917|
|Taxonomic Notes:||Squalus brevirostris from the northwest Pacific has previously been considered a synonym of S. megalops. A recent revision of Indo-Pacific Squalus species revealed that this species is clearly separable from the true S. megalops from Australia (Last et al. 2007). Misidentifications of the Squalus species in the northwest Pacific is an issue and may affect the quality of data available for this species.|
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Reviewer(s):||Valenti, S.V., Tanaka, S. & Fowler, S.L. (Shark Red List Authority)|
The Japanese Shortnose Spurdog (Squalus brevirostris) is a dogfish occurring from Southern Japan to the South China Sea including Ryukyu Islands and Vietnam. Japanese Shortnose Spurdog from the northwest Pacific has previously been considered a synonym of the Piked Spurdog (Squalus megalops), however a recent study revealed that this species is clearly separable from the true S. megalops from Australia. Misidentification of Squalus species in the northwest Pacific is an issue and affects the quality of data available. This species is apparently still commonly caught in deepwater demersal fisheries in Japan and Taiwan, Province of China. There is little information currently available and it is probably confused with other Squalus species in the literature. The lack of information precludes an assessment beyond Data Deficient at present and efforts should be made to quantify bycatch and to determine population trends.
|Range Description:||Northwest Pacific: southern Japan to the South China Sea including Ryukyu Islands and Viet Nam (Last et al. 2007).|
Native:China; Japan (Nansei-shoto); Viet Nam
|FAO Marine Fishing Areas:||
Pacific – northwest; Pacific – western central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Commonly caught in some areas of Japan and Taiwan and appears to be relatively abundant.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Habitat and biology are poorly known. The largest catalogued specimen is a female measuring 55.2 cm total length (TL). Adult males measure ~45 cm TL (Last et al. 2007).|
Caught by bottom trawls and longlines in some parts of its range. Fisheries off the eastern coast of Taiwan, Province of China have moved into deeper water over the past 20 years, particularly around Ta-Shi, from 100-300 m fishing depth to >300 m currently (D. Ebert pers. comm. 2007).
Squlaus species are recorded in catches off Vietnam (SEAFDEC 2006) but nothing is known of the amount of this species taken or the level and impact of fisheries on this species. For example, bottom longline fisheries operate around the Paracel islands, Vietnam at depths >100 m. Sharks account for 45-100% of the total catch with 400-4,000 kg captured per boat (N. long pers. comm. 2007), however, no species specific information is available. In southern Vietnam, off Phu Quy island only about a 100 boats are still targeting sharks due to a general decline in the level of shark catch (N. long pers. comm. 2007), however no data are available to confirm which species have been impacted. In this area fishing boats have switched to targeting snapper and grouper or cuttlefish and squid (N. long pers. comm. 2007).
Other Squalus species in the northwest and Western Central Pacific are targeted and valuable for their liver oil, however, because of species misidentification and confusion no specific information on the utilization of this species is currently available.
|Conservation Actions:||None in place. Efforts should be made to collect species specific catch data. Future surveys should aim to further define this species' distribution and identify population trends.|
|Citation:||White, W.T. 2009. Squalus brevirostris. The IUCN Red List of Threatened Species 2009: e.T161438A5423985. http://dx.doi.org/10.2305/IUCN.UK.2009-2.RLTS.T161438A5423985.en . Downloaded on 04 October 2015.|
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