|Scientific Name:||Galeus atlanticus (Vaillant, 1888)|
Pristiurus atlanticus Vaillant, 1888
|Taxonomic Source(s):||Eschmeyer, W.N. (ed.). 2015. Catalog of Fishes. Updated 6 April 2015. Available at: http://researcharchive.calacademy.org/research/ichthyology/catalog/fishcatmain.asp. (Accessed: 6 April 2015).|
Previously this species was synonymized with Galeus melastomus, but it is now considered a valid species supported by both morphometric external field marks and genetic evidence (Muñoz-Chapuli and Perez-Ortega 1985; Rey et al. 2005, 2006, 2010; Castilho et al. 2007).
|Red List Category & Criteria:||Near Threatened (Regional assessment) ver 3.1|
|Assessor(s):||Coelho, R.P., Rey, J., Serena, F., Mancusi, C. & Guallart, J.|
|Reviewer(s):||Séret, B. & Walls, R.|
|Facilitator/Compiler(s):||Lawson, J., Walls, R. & Dulvy, N.|
European regional assessment: Near Threatened (NT)
Atlantic Sawtail Catshark (Galeus atlanticus) is a little known and rare demersal catshark reported at depths ranging from 330−790 m, with a narrow extent of occurrence (approximately 50,000 km2). It is still probably misidentified as Blackmouth Catshark (Galeus melastomus) and African Sawtail Catshark (G. polli). It is taken as bycatch throughout its entire depth and geographic range by deepwater fisheries. It is usually discarded but post-release survival rates are unknown and assumed to be low, and larger individuals are retained for sale. The species is suspected to have undergone a decline of nearly 30% over the three-generation period (36-45 years), being close to qualifying as threatened under Criterion A2, and it is therefore assessed as Near Threatened due to the heavy fishing pressure it suffers throughout this small range. Catches of this species should be correctly identified and carefully monitored.
This catshark has a very narrow range in all the regions in which it occurs. Some identification problems and possible confusion with Blackmouth Catshark (Galeus melastomus) and African Sawtail Catshark (G. polli) indicate that the range may be larger than currently known. The total extent of occurrence (EOO) is around 50,000 km2, from which approximately 25,000 km2 is in the Northeast Atlantic and 25,000 km2 is in the Mediterranean Sea.
In the Northeast Atlantic this species has been reported off the southwest coast of Portugal (Coelho and Erzini 2008), where it is captured regularly. In the Eastern Central Atlantic, this shark has been reported off West Africa, but only from a single type specimen captured off Cape Spartel on northwest coast of Morocco, and from one specimen captured off Mauritania (Castilho et al. 2007). In the Mediterranean Sea it has been reported in Spanish waters, from the Gibraltar Strait in the west to Cape Gata to the east.
Its depth range is 330-710 m.
Native:Algeria; Morocco; Portugal (Portugal (mainland)); Spain (Spain (mainland), Spanish North African Territories)
|FAO Marine Fishing Areas:|
Atlantic – northeast; Atlantic – eastern central; Mediterranean and Black Sea
The International Trawl Survey in the Mediterranean (MEDITS) program covers the north Mediterranean coast almost continuously from western Morocco and Spain in the west to the Aegean Sea in the east. Six trawl surveys were carried out in the coastal areas of four arbitrary geographically defined areas: Western (Morocco, Spain, France), Western Central (Tyrrhenian, Corsican, Sardinia and Sicily coasts), Eastern Central (Adriatic, Ionian and Albanian coasts) and the Eastern (Aegean Sea). This catshark was only captured in one (0.01%) out of 6,336 tows performed between 1994 and 1999 at depths ranging from 10 to 800 m (Baino et al. 2001). However, it is likely that it was still being confused for Blackmouth Catshark at this time. Spanish MEDITS data indicate that it only occurs in the western Mediterranean Sea, from the Straits of Gibraltar to Cape Gata. High numbers of juveniles have only been reported from the Alboran Sea (Rey et al. 2005, 2010), and abundance decreases gradually towards Cape Gata (Rey et al. 2005, 2010). In the Eastern Central Atlantic this species has only been confirmed from West African waters from the holotype specimen that was captured off cape Spartel of northwest Morocco (Vaillant 1888), and from a specimen caught off Mauritania (Castilho et al. 2007). It is unknown if it is very rare in this area or is just misidentified as Blackmouth Catshark and African Sawtail Catshark. Based on the rarity of this catshark and the fact that it exists within a very narrow depth and geographic range that entirely overlaps with fisheries, the population is suspected to have undergone a decline of nearly 30% for the three generation period (36-45 years). While there have been no estimates of post-release survival rates after incidental capture and discarding, a precautionary assumption should be made that survival might be low.
|Current Population Trend:||Decreasing|
|Habitat and Ecology:|
This catshark is a demersal species occurring at depths of 330−710 m (Compagno et al. 2005, Rey et al. 2005).
This egg laying species produces egg cases that are 11−13 mm by 38−40 mm in size (Bauchot 1987) with up to nine egg cases in one female, suggesting a short hatching period outside the mother (Compagno et al. 2005). Bauchot (1987) measured a mature female of 39.8 cm total length (TL) and a male of 38.4 cm TL, while Compagno et al. (2005) estimated that females mature at sizes between 40 and 45 cm TL males mature between ~ 38 and 42 cm TL. Maximum size is ~ 45 cm TL (Compagno et al. 2005).
Other similar-sized temperature Galeus species mature at 9.14 and 7.57 years for females and males respectively, and have a longevity of 20.9 and 12.4 years, which suggest generation spans of 9.98 and 15.02 years (Liu et al. 2011) Therefore the generation length of Galeus atlanticus is suspected to be between 12-15 years.
|Generation Length (years):||12-15|
|Use and Trade:||There is no information on the use and trade of this species.|
This species apparently is commonly misidentified in fisheries data as Blackmouth Catshark as they are externally very similar. It is caught as bycatch by commercial trawl nets and bottom longlines on slope bottoms and it is a bycatch in the semi-industrial and artisanal trawl, gillnet and longline fisheries (Bauchot 1987, Serena 2005). Deepwater trawlers targeting crustaceans such as Norway Lobster (Nephrops norvegicus) and Red Shrimp (Aristeus antennatus) operate intensively throughout the Alboran Sea. This catshark is most abundant in the Alboran Sea and these trawlers operate throughout the entire depth range and area of occupancy of this species in this region, making it susceptible to capture throughout its entire AOO.
Off the south coast of Portugal (Algarve), this catshark is a bycatch of the deepwater longline fishery that targets Wreck Fish (Polyprion americanus) and Conger Eels (Conger conger), and of deepwater trawlers targeting crustaceans such as Norway Lobster, Red Shrimp and Pink Shrimp (Parapenaeus longirostris; Coelho and Erzini 2008). Most specimens are discarded, although the larger specimens have some commercial value and may be sold for human consumption. Most of the discarded specimens are still alive when returned to sea, but usually have severe injuries that are likely to impair their survival. In Portuguese fisheries statistics from these fisheries, marketed specimens are mixed with and recorded as Blackmouth Catshark, making it impossible to discern trends of commercial captures through time. Currently, the entire AOO in the Northeast Atlantic is being heavily fished either by deepwater trawlers or deepwater longliners, so the entire population in this region is likely undergoing fishing mortality. Off cape Spartel, where the type specimen was recorded, there has been a deepwater longline fishery operating throughout this species’ depth range since 2001, targeting Black Scabbardfish (Aphanopus carbo). In the same area and depth range there is a deepwater trawl fishery targeting crustaceans. It is likely that both fisheries are taking this species as bycatch but data are unavailable.
Based on advice from the International Council for the Exploration of the Sea (ICES) to end fishing for deepwater sharks, the European Union (EU) Fisheries Council in 2007 established and began gradual reductions for a Total Allowable Catch (TAC) quota covering several shark species, not including Atlantic Sawtail Shark. In 2010, the EU Council added four deepwater shark species to the measure, and set the deepwater shark TAC at zero, starting in 2012. In 2013, in response to ICES advice, the list of species covered by the deepwater shark TAC was amended to exclude Blackmouth Catshark. Owing to the lack of differentiation between Atlantic Sawtail Catshark and Blackmouth Catshark in commercial fisheries catch, strong fishing pressure is expected for this species within its restricted range. In this area (mainly Alboran Sea and south Portugal) mid- or long-term surveillance of abundance in fisheries (longline and bottom trawl) is necessary. Fishery observers should start separating this species from Blackmouth Catshark and African Sawtail Catshark. Further research should be conducted on the population size and trend of the species.
|Citation:||Coelho, R.P., Rey, J., Serena, F., Mancusi, C. & Guallart, J. 2015. Galeus atlanticus. The IUCN Red List of Threatened Species 2015: e.T63149A48918561.Downloaded on 17 August 2018.|
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