|Scientific Name:||Galeus eastmani|
|Species Authority:||(Jordan & Snyder, 1904)|
Pristiurus eastmani Jordan & Snyder, 1904
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Iglésias, S., Tanaka, S., Nakaya, S. & McCormack, C.|
|Reviewer(s):||Valenti, S.V. & Stevens, J.D. (Shark Red List Authority)|
A small (to at least 40 cm TL) deepwater catshark which occurs off southern Japan, and Taiwan Province of China in the East China Sea. Records from Vietnam are probably erroneous. It is found on or near the seabed and is reported to occur at depths of 100–900 m. This species is reportedly very common off southern Japan. It is taken as bycatch of deepwater trawl fisheries operating within its range and is utilized for fishmeal. Despite continued fishing pressure from trawl fisheries during past decades, this species still appears to be common and there is no evidence to suggest that it has declined. This is a small, locally abundant, oviparous species and may be less vulnerable to depletion in fisheries than larger, live-bearing species. Furthermore, the species may have some spatial refuge, outside the range of current fishing pressure at the deeper extent of its bathymetric range. Given that there is no evidence to suggest that this species has declined, it is assessed as Least Concern. Catch levels and population trends should be monitored.
|Range Description:||Northwest Pacific: southern Japan and East China Sea (Compagno et al. 2005), including Taiwan, Province of China (S. Iglésias pers. obs. 2007). It is also reported from Vietnam, but records from there may be inaccurate (L.J.V. Compagno pers. comm. 2007).|
Native:Japan; Taiwan, Province of China
|FAO Marine Fishing Areas:||
Pacific – northwest; Pacific – western central
|Lower depth limit (metres):||900|
|Upper depth limit (metres):||100|
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||The species is little known but apparently very common in Japanese waters (Compagno et al. 2005).|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Found in deep water on or near the bottom (Compagno 1984, Compagno et al. 2005). In Suruga Bay, Japan it is reported to occur at depths of 100 m to as deep as 900 m (Horie and Tanaka 2000, Okamura et al. 1984). Attains a maximum length of at least 40 cm total length (TL), probably reaching 50 cm (Compagno 1984, Horie and Tanaka 2000). Males mature at about 31–32 cm and females at around 36–37 cm (Compagno 1984, Compagno et al. 2005, Horie and Tanaka 2000). Reproduction is oviparous with a single egg laid per oviduct (Compagno 1984, Nakaya 1975). Females carrying egg-cases were observed from October to January (Horie and Tanaka 2000). The species shows sexual segregation in Japanese waters with reported schools of mostly females (Compagno 1984, Nakaya 1975). An immature male observed at a fish market in Taiwan, Province of China, measured 38 cm TL (S. Iglésias pers. obs.).
In Suruga Bay, Japan, females were recorded more frequently than males; yearly average CPUE of females was 1.84 per fishing tow compared to 0.53 per fishing tow for males from 1981 to 1996. This species mainly eats cephalopods and crustaceans, although prey items vary with size (Horie and Tanaka 2000).
This species is a bycatch of commercial deepwater trawl fisheries in the northwest Pacific, but no data are available on its capture (Horie and Tanaka 2000, S. Iglésias pers. obs. 2007). It is infrequently observed at the Tachi and Nan Fang Hao fish markets in Taiwan, Province of China and is utilized with other bycatch species as fishmeal for aquaculture. The small mesh size of trawl nets means that both adults and most juveniles are captured and retained by trawls (S. Iglésias pers. obs.).
Although the species is taken as bycatch of deepwater fisheries, it is apparently still common off Japan. Furthermore, the species may have some spatial refuge, outside the range of current fishing pressure at the deeper extent of its bathymetric range.
No management or conservation efforts are currently in place. Like many deeper water species more information on biology, ecology and importance in fisheries are required to further assess status and any future conservation needs. Where taken, catches require monitoring, particularly as deepwater fisheries expand worldwide.
The development and implementation of management plans (national and/or regional e.g., under the FAO International Plan of Action for the Conservation and Management of Sharks: IPOA-Sharks) are required to facilitate the conservation and management of all chondrichthyan species in the region.
|Citation:||Iglésias, S., Tanaka, S., Nakaya, S. & McCormack, C. 2009. Galeus eastmani. The IUCN Red List of Threatened Species 2009: e.T161364A5406962. . Downloaded on 24 May 2016.|
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