|Scientific Name:||Hydrolagus affinis (de Brito Capello, 1868)|
|Taxonomic Notes:||Appearance is very similar to Hydrolagus pallidus. H. affinis is distinguished primarily by its darker body color compared to the much paler H. pallidus (Hardy and Stehmann 1990).|
|Red List Category & Criteria:||Least Concern ver 3.1|
|Assessor(s):||Dagit, D.D. & Clarke, M.W.|
|Reviewer(s):||Kyne, P.M., Cavanagh, R.D. & Kulka, D.W. (Shark Red List Authority)|
A deepwater slope, seamount and seaplain dwelling fish reported at depths of 300 to 2,410 m, most commonly found below 1,000 m. This species appears to be widespread in the northern Atlantic. Almost nothing is known of population size, biology and reproduction in this species and most captures are large adults near or >100 cm TL. Likely a slow-growing species with low fecundity. Not commonly captured except in deepwater research trawls and occasionally as bycatch in deepwater commercial trawls. Potentially threatened by emerging deepwater commercial trawl fisheries in the North Atlantic. However, this species is present deeper than the main fisheries operating within its range and it is therefore considered Least Concern. Furthermore, it may be distributed at greater depths than currently reported offering a deep refuge from fishing pressure. Although it is considered unlikely that fisheries will ever target this species due to its low abundance, study of population size, and age and growth is highly recommended as this may be a slow-growing species that could be affected by bycatch.
|Range Description:||Primarily occurring in the central and eastern north Atlantic, but also captured in the western Atlantic. Probably widespread throughout the northern Atlantic with greatest abundance at depths greater than 1,000 m.|
Native:Canada (Labrador, Newfoundland I); France; Greenland; Iceland; Ireland; Portugal; Spain (Canary Is.); United Kingdom; United States
|FAO Marine Fishing Areas:|
Atlantic – northeast; Atlantic – northwest; Atlantic – eastern central
|Range Map:||Click here to open the map viewer and explore range.|
|Population:||Nothing is known of population size or structure. Almost all captures are large adults or subadult juveniles at or >100 cm TL. Very few small juveniles have ever been collected indicating that juveniles and adults may aggregate separately and occupy different habitats. |
H. affinis is only rarely encountered in Canadian waters, in 70 of about 42,000 survey sets most of which occurred at >1,000 m (87% of captures were at >1,000 m) (D. Kulka pers comm).
|Current Population Trend:||Unknown|
|Habitat and Ecology:||Occurs on deepwater slopes, seamounts, and seaplains of the north Atlantic at depths of 300 to 2,410 m, generally occurring in waters near or below 1,000 m (Stehmann and Bürkel 1984, Krefft 1990). Size range 32 to 147 cm total length (TL); 14 to 96 cm body length (BDL). |
Nothing is known of biology and ecology of this species. Diet probably consists of a variety of bottom dwelling invertebrates and other fish. Oviparous but nothing is known of reproduction, spawning or growth. It is likely that this is a slow-growing species with low fecundity.
Not commonly captured except when collected in deepwater research trawls and possibly as a bycatch in some deep water trawls. Not known to be targeted at present and it is not considered a likely future target due to its low abundance. Could face a potential threat in the future if emerging deep water commercial trawl fisheries capture this large species in large numbers, however H. affinis is considered to occur deeper than the main fisheries in the Northeast Atlantic, offering a deep refuge from fishing pressure. As this species is thought to be slow growing with low fecundity, monitoring of deepwater fishing activities, including landings and discards will be essential to ensure that this species is not adversely affected.
Areas of the Northeast Atlantic, for example the Rockall Trough have been subject to a fairly rapid increase in deepwater fishing activities since the 1990s with overall concern for the sustainability of deepwater fish stocks (Gordon 2003). Since 1998 Norwegian trawlers and longliners have carried out trial and commercial fisheries in the Hatton Bank area (ICES VIb and XII) at depths between 600 to 2,000 m (Kjerstad et al. 2003). However, the lower depth limit of fisheries in this region may be about 1,500 m.
In the northwest Atlantic, deepest fishing sets occur at 1,500 m off Newfoundland (most deep fishing in the range of 700 to 1,200 m), and 400 m off Nova Scotia (D. Kulka pers. comm.). About 10-20% of the Northwest Atlantic slope is fished annually (D. Kulka pers. comm).
This species' wide depth distribution and they are more commonly caught at depths greater than 1,000 m offer refuge from fishing pressure. Not commonly captured except when collected in deepwater research trawls and possibly as a bycatch in some deep water trawls. Could face a potential threat in the future if emerging deep water commercial trawl fisheries capture this large species in large numbers as a target or bycatch fisher.
|Conservation Actions:||No management or conservation measures are known to be in place. Study of population size, and age and growth of this species is recommended prior to initiating any target fishery as this may be a slow-growing species that would be highly threatened by overfishing. Management and monitoring of captures of this species should be a priority.|
|Citation:||Dagit, D.D. & Clarke, M.W. 2007. Hydrolagus affinis. The IUCN Red List of Threatened Species 2007: e.T63123A12616352.Downloaded on 25 April 2018.|
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