|Scientific Name:||Deania profundorum|
|Species Authority:||(Smith & Radcliffe, 1912)|
Deania profundora (Smith & Radcliffe, 1912)
Nasisqualus profundorum Smith & Radcliffe, 1912
|Taxonomic Notes:||There are at least two common birdbeaked dogfish known from Namibian waters with two less common species rarely taken in very deepwater. A taxonomic review of this group is required to properly identify the species of this genus.|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor/s:||Ebert, D.A., McCormack, C. & Samiengo, B.|
|Reviewer/s:||Cavanagh, R.D., Huepel, M., Simpfendorfer, C., Valenti, S.V. & Burgess, G. (Shark Red List Authority)|
The Arrowhead Dogfish (Deania profundora) is a moderate sized (to 104 cm but mostly around 80 cm) dogfish found on or near the bottom at depths of 275?1,785 m on the upper continental and insular slopes. It is often found in huge aggregations, possibly increasing the threat of overfishing where fisheries occur. There is little information on the catch of this species but deepwater fisheries operate over much of its range (e.g., Canary Islands, the Azores, off Namibia and in the Gulf of Mexico). This species is taken on longlines off the Canary Islands and utilized for liver oil and meat. It may also be taken by an experimental deepsea tanglenet fishery off Namibia, where identification of the Deania species being caught is uncertain. Observations suggest they may be more common in the deeper end of their bathymetric range. There are no known deepwater fisheries currently operating off South Africa and the Philippines and these areas may provide a refuge from fishing pressure. Given this species? relatively wide geographic and bathymetric range and the absence of data to suggest significant declines, this species is assessed as Least Concern. Expanding fisheries should be monitored as they move into deeper water.
|Range Description:||Western Central Atlantic: USA (Atlantic coast off North Carolina, Gulf of Mexico off Mississippi), and the lesser Antilles (Dominica). Eastern central Atlantic: Western Sahara, Mauritania, Senegal, Canary Islands, the Azores, Nigeria, Gabon, Zaire. Southeast Atlantic: Namibia, South Africa (Northern and Western Provinces). Western Indian Ocean: South Africa (KwaZulu-Natal), Walters Shoal, Gulf of Aden. Western central Pacific: Philippines (Mindinao, Leyte, Luzon, Marinduque, Siquijor and Bohol) (Compagno in prep.).|
Native:Congo, The Democratic Republic of the; Dominica; Gabon; Mauritania; Namibia; Nigeria; Philippines; Portugal (Azores); Senegal; South Africa (KwaZulu-Natal, Northern Cape Province, North-West Province, Western Cape); Spain (Canary Is.); United States (Mississippi, North Carolina); Western Sahara
|FAO Marine Fishing Areas:||
Atlantic – eastern central; Atlantic – southeast; Atlantic – western central; Indian Ocean – eastern; Indian Ocean – western
|Range Map:||Click here to open the map viewer and explore range.|
Very little information is available on population throughout this species? range.
This species was recorded in annual deepwater scientific research cruises conducted off Namibia from 2004?2006 (at 500?2,000 m depth), down to 1,000 m (H. Holtzhausen pers. comm. 2007). It appears to be scarce off Namibia, with a small biomass of about 160 tons in the areas surveyed (H. Holtzhausen pers. comm. 2007).
|Habitat and Ecology:||
The following information is taken from Compagno (in prep.) unless cited otherwise.
A deepwater species of continental and insular slopes found on or near the bottom at depths from 275?1,785 m. In the Northwest Atlantic it occurs at 412?617 m depth; in the Azores from 250?1,100 m, mostly commonly between 700 and 800 m (M.R. Pinho pers. comm. 2006); off the Canary Islands it has been caught at 600?1,500 m; off southern Africa it occurs at 500?608 m; and off the Philippines it is known at 717?1,786 m. It has been trawled on mud and coral bottoms in the Philippines. Observations suggest they may be more common in the deeper end of their bathymetric range (D. Ebert pers. obs. 2007).
Size at birth is over 31 cm. Adult males are 43?67 cm. Females are immature at 60?77 cm, adolescent at 65?79 cm and adult at 62?80 cm. Maximum total length (TL) is reported at about 104 cm (M.R. Pinho pers. comm. 2006), but most known individuals are smaller.
The species sometimes occurs in huge aggregations or schools. Reproduction is ovoviviparous. The probable litter size is five to seven judging from fertilized eggs in the uteri of females (Compagno et al. 1989). The species feeds on small benthic and midwater bony fishes, including lanternfish, as well as squids and crustaceans. Off the West Coast of South Africa squids (Ommastrephidae, Abraliopsis species, and unidentified cephalopods) and lanternfish (particularly Diaphus, Myctophidae) are important prey items (Ebert et al. 1992).
Feeds on small bottom and midwater fish, squid and crustaceans (Ebert et al. 1992).
This species is caught on longlines off the Canary Islands and utilized for liver oil and meat (Compagno in prep.). It is probably caught as bycatch by deepwater fisheries elsewhere in its range.
In the Azores, there is no information from the fishery but only a small number of individuals are caught as bycatch, because the core of the species' distribution is outside of the area where the local fleet usually operates (M.R. Pinho pers. comm. 2006). Some deepwater fishing has been conducted for deepwater sharks off Senegal. Off Kayar and Dakar, Senegal, an artisanal fishery targets Centrophorus species for their liver oil (Direction des Pêches Maritimes du Sénégal 2007). The fishery uses gillnets to target deepwater sharks for part of the year. Deania profundora is not reported in the catch and may occur at greater depths than currently fished off western Africa. Fisheries are beginning to operate in deeper waters due to declines in catches of more coastal species (L. Mbaye pers. comm. 2007).
Off Namibia, a fairly small amount of demersal sharks are caught as bycatch by deep-water trawl fisheries and recorded as ?sharks? or ?other? (NATMIRC 2003). These fisheries target hake from 400 to 600 m off Central Namibia (around 100 vessels), monkfish at 600 m off central Namibia (around 20 vessels) and orange roughy from 600 to 1,000 m off northern Namibia (three vessels) (NATMIRC 2003). Two vessels were also granted two-year exploratory rights to target deep-water shark species along the entire coast of Namibia using tanglenets (NATMIRC 2003). Birdbeaked dogfish were being fished in this experimental deepsea fishery, but the identification of what Deania species was being caught is uncertain (D. Ebert pers. comm. 2007). The main species of deepwater shark taken by Namibian fisheries are Centrophorus squamosus, Centroscymnus coelolepis, Deania quadrispinosum, Squalus mitsukurii and Galeorhinus galeus (NATMIRC 2003). The experimental fishery ended in January 2006.
In the Gulf of Mexico, there are some fisheries presently operating in deeper water. For example, Royal Red shrimp trawlers, golden crab traps (180?550 m), bottom longline for tilefish (around 150?350 m), deep drop hook and line boats in the Straits and the Gulf. Almost all the bottom longline boats that target deepwater grouper in the Gulf, and sharks in the Straits and in the Gulf, are setting in depths greater than around 150 m. These bottom long liners catch deep water skates and sharks sporadically. There is also a bottom trawler that fishes for butterfish in deep water and catches deep water skates and sharks fairly regularly (G. Davenport pers. comm. 2006). It is unknown whether this species is taken by any of these fisheries.
There are currently no deepwater fisheries operating within the species? range off South Africa or the Philippines; however, given the expanding trend in deepwater fisheries worldwide, the situation should be carefully monitored to ensure that the species is not adversely affected.
|Conservation Actions:||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.|
|Citation:||Ebert, D.A., McCormack, C. & Samiengo, B. 2009. Deania profundorum. In: IUCN 2013. IUCN Red List of Threatened Species. Version 2013.2. <www.iucnredlist.org>. Downloaded on 24 April 2014.|
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