Sharks and Skates of Scotland Report: Arctic skate (Amblyraja hyperborea)

Habitat 

Arctic skate are a polar species with a wide distribution among across the Arctic seas and shelves. Its range extends from eastern Canada to Greenland and across to Russia and Siberia (Barents, Kara and Laptev Seas) and between Russia and western Canada (Chukchi and Beaufort Seas). It also occurs in more localised areas of the southern hemisphere, for example, off the southern tips of Australia, South Africa, around New Zealand and some areas off South America (Agustin and Capuli, 2019; Kulka et al., 2016). Arctic skate are not common in much of Europe other than the deep arctic water of the Faroe-Shetland Channel (Baxter et al., 2011).  

Biology and Ecology

Arctic skate are oviparous, laying egg capsules that range from 81 -125 mm long and 50 – 80 mm wide (Ebert 2014). The size of hatched individuals ranges from 16-18 cm TL (Stehmann et al., 2015). Maximum size is recorded as possibly as high as 97 cm in the Northeast Atlantic (Kulka et al., 2024). Females in the North Atlantic were found to mature at approximately 71 cm, and males at 67 cm (López Climent 2021). Egg nurseries have been found in association with cold water coral reefs on deep-water seamounts in the waters off Tasmania (Maguire et al., 2023). The age at maturity is unknown. Arctic skate are opportunistic feeders and consume benthic animals (e.g. prawn) as well as pelagic species such as herring (Clupea harengus), blue whiting (Micromesistius poutassou) and capelin (Mallotus villosus) (Bjelland et al., 2000; Benzik and Chetyrkin 2022). A recent survey in the Northwest Atlantic found that they are capable of feeding on animals 50% to 80% of their own size, such as eelpout (Zoarcidae sp) (Byrkjedal et al., 2015). Video footage of Arctic skate in-situ in the Pacific Ocean revealed typically slow and deliberate swimming activity, skates were observed skimming the seafloor and using a combination of ‘punting’ (a form of locomotion utilised by skates whereby the pelvic fins are used to ‘walk’) and undulatory swimming (Kuhnz et al., 2019).  

Human interactions 

Arctic skate generally have limited interaction with fisheries due to its occurrence at depth (Kulka et al., 2016). However, it may be represented in the bycatch of longline and deep-water trawl fisheries in certain areas, such as the cod and haddock fisheries of Northeast Atlantic and longline fisheries targeting mainly Greenland Halibut (Reinhardtius hippoglossoides), Cod (Gadus morhua) and Northern wolfish (Anarhichas denticulatus). Arctic skate have been reported as a significant bycatch species, along with Greenland sharks (Somniosus microcephalus), in the Greenland halibut fisheries in the Canadian Arctic (Peklova et al., 2014) and in the Barent Sea Arctic skate  accounted for approximately 20% of longline catches between 1996 - 2001, at times comprising 99% of some catches (Kulka et al., 2016). Discarding of this species is known to take place but has not been quantified, and discard survival has not been estimated (ICES, 2018, 2019). Arctic skate are managed under a combined regional TACs for ‘skates and rays’ in Scottish waters as part of the Celtic Seas ecoregion and the Greater North Seas ecoregions (Batsleer et al., 2024). However, since the introduction of general measures to protect deep-water elasmobranchs (ban of static net fisheries below 600 m and trawls below 800 m; ICES 2024), the species has unlikely to be incidentally captured due to the depths at which it occurs.