|Scientific Name:||Centroscyllium excelsum Shirai & Nakaya, 1990|
|Red List Category & Criteria:||Data Deficient ver 3.1|
|Assessor(s):||McCormack, C., Nakaya, K. & Samiengo, B.|
|Reviewer(s):||Valenti, S.V. & Fowler, S.L. (Shark Red List Authority)|
This little known small (to at least 63.6 cm total length) deepwater shark is endemic to the Emperor Seamount Chain east of Japan and the Kuril Islands in the northwest Pacific Ocean at 80-1,000 m depth. The Highfin Dogfish (Centroscyllium excelsum) is known from very few specimens and its biology is largely unknown. Some offshore trawlers off Japan fish on the Emperor Seamounts, however, there are no data available to determine whether this species is taken. If fishing occurs within the depth range of this species, its restricted distribution makes it vulnerable to overfishing. Insufficient information is available to assess this species beyond Data Deficient and efforts should be made to determine the level of threat to this potentially biologically vulnerable species.
|Range Description:||Northwest Pacific: known only from the Emperor Seamount Chain east of Japan and the Kuril Islands at the type locality, 38°37' to 49°59'N, 171°06' to 170°00'E (Compagno in prep.).|
Native:Japan; Russian Federation (Kuril Is.)
|FAO Marine Fishing Areas:|
Pacific – northwest
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Only known from 21 specimens.|
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Found on or near the bottom at depths of 800-1,000 m. Only 21 specimens have been collected and biology is largely unknown. The species attains at least 63.6 cm total length (TL) (Shirai and Nakaya 1990). Mature specimens have measured from 53 cm TL and 52 cm TL for females and males respectively. Reproduction is ovoviviparous. A litter of 10 was found in one pregnant female and size at birth has been estimated at 8-9.3 cm (near-term fetuses). The Highfin Dogfish feeds on bony fishes (Shirai and Nakaya 1990, Compagno in prep.).|
The restricted distribution of the species may make it vulnerable to deep-sea trawl and longline fisheries, especially those that can accurately target deepwater teleosts on restricted deepwater bottom habitats including the slopes of seamounts (Compagno in prep.).
While some trawlers off Japan are restricted to fishing within the borders of their prefectures, others conduct fisheries on the Emperor Seamounts (H. Ishihara pers. comm. 2006). Fisheries have operated on the Emperor seamount chain since the 1960s. Some of these have led to dramatic declines in the target stock but there is no information to determine whether this species was taken as bycatch. For example, Japanese and former USSR vessels began targeting armourheads (Pseudopentaceros species) with trawls in the Emperor Seamount chain and the northern Hawaiian Ridge areas in 1969 (Maguire et al. 2006). Between 1969 and 1977, the Japanese fleet sent two to five trawlers a year to this area and averaged catches of 22,800 to 35,100 tonnes a year. By 1977 to 1982 catches had fallen to 5,800-9,900 tonnes a year (Maguire et al. 2006). Pseudopentaceros species occur to 600 m depth. There is no evidence that either of the fish stocks will recover enough to allow commercially viable fisheries in the near future (Maguire et al. 2006).
There is no information to determine whether this species is taken in fisheries on the Emperor Seamount chain and the Kuril Islands, but any bycatch is of concern given the species' limited range. Furthermore, the species may have limiting life history characteristics, similar to other deepwater shark species, thus will not be sufficiently fecund to withstand high levels of exploitation.
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. Data are required to determine whether this species is captured in fisheries operating throughout its range.
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:||McCormack, C., Nakaya, K. & Samiengo, B. 2009. Centroscyllium excelsum. The IUCN Red List of Threatened Species 2009: e.T161740A5492923.Downloaded on 15 October 2018.|
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