Sharks and Skates of Scotland Report: Mid-Atlantic skate (Rajella kukujevi)
An extract from the Sharks and Skates of Scotland Report.
Mid-Atlantic skate - Rajella kukujevi (Dolganov, 1985)
Occurrence in Scotland: Slope and deep-water. Occasional. Found on the slopes both sides of the Rockall Trough, around Rockall, Rosemary Bank, and the continental shelf off NW Scotland.
Synonym(s): Raja kukujevi; Order: Rajiformes; Family: Rajidae
Common name: Mid-Atlantic skate
AlphaID: 105895 TSN Code: 564220
Note: Rajella kukujevi are a data-deficient species, and it is recommended that the assessment of ‘Least Concern’ is revised as soon as more data becomes available (Dulvy, 2015).
Population status
Scotland and Northeast Atlantic: Stable. Based on lack of overlap with deepwater fisheries (Dulvy et al., 2015; ICES, 2024).
Global: Stable. Population trend is unknown for the Mid-Atlantic Skate, although it is suspected to be stable based on minimal overlap with deepwater fisheries (Dulvy et al., 2024).
Conservation listings
- IUCN Red List Global: Least Concern (assessment 02 May 2023)
- CITES: Not listed
- CMS: Not listed
- OSPAR: Not listed
Range and distribution
Mid-Atlantic skate are endemic to the Northeast and Eastern Central Atlantic Oceans, and have been recorded in the Mid-Atlantic Ridge, from Iceland, the Faeroes EEZ, and in deep-water areas down the west coast of Scotland and Ireland to Bay of Biscay (Rodríguez-Cabello et al., 2012; Ebert and Stehmann, 2013; Dulvy, 2015; Last et al., 2016; Dulvy et al., 2024). Off the west coast of Scotland, the species are mostly caught in the Rockall Trough (Dulvy, 2015).
ICES DATRAS records for Mid-Atlantic skate (Rajella kukujevi), 2000: 2000-2009.
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ap of the EEZ of Scotland showing the ICES (International Council for the Exploration of the Sea) DATRAS (database of trawl surveys hosted by ICES) records for Mid-Atlantic skate (Rajella kukujevi) from bottom trawl surveys conducted between 2000 and 2009. Red points represent trawl shoot positions in which Mid-Atlantic skate (R. kukujevi) were captured. There is a single record indicating that Mid-Atlantic skate (R. kukujevi) were recorded in a single trawl off the continental shelf to the west of the Isle of Barra.
Records for Mid-Atlantic skate (Rajella kukujevi) from SIAMISS and deep-water fisheries surveys undertaken by the Marine Directorate 1996 – 2019.
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Map of the economic exclusion zone (EEZ) of Scotland showing records for Mid-Atlantic skate (Rajella kukujevi) from the Scottish-Irish anglerfish and megrim industry-science survey (SIAMISS) and deep-water fisheries surveys undertaken by Marine Directorate from 1996 to 2019. Records are illustrated as green points and are exclusively located off the west coast of Scotland and Northern Ireland off the edge of the continental shelf. Most records are just off the edge of the continental shelf on the continental slope but there are a few north west of the Outer Hebrides further out in deeper water and some around the Rockall Plateau.
Habitat
Mid-Atlantic skate are a deep-water species, recorded on outer continental slopes and upper abyssal plain at depths of 750–2,190 m (Ebert and Stehmann 2013, Last et al. 2016), but is most frequently recorded from 1,000–1,600 m (Orlov 2014).
Biology and Ecology
There is very little data on the reproductive biology or diet of Mid-Atlantic skate, but they are presumed to lay eggs like other Rajidae. Iglésias (2012) reported a maximum size of 79–84 cm TL for mature males, while Rodriguez-Caballo (2012) reported maximum sizes of 56.8 and 72.9 cm TL for males and females, respectively. Nothing is known about size at maturity.
Human interactions
There is relatively little risk of capture by trawl and gillnet fisheries from either European (EU) or United Kingdom (UK) fleets due to the deep waters that they inhabit, which are beyond the reach of most deep-water fishing vessels following the introduction of general measures to protect deep-water elasmobranchs (i.e. ban of certain net fisheries below 600 m, and trawls below 800 m) (ICES 2024).
References
Dulvy, N. 2015. Rajella kukujevi (Europe assessment) (errata version published in 2024). The IUCN Red List of Threatened Species 2015: e.T161622A258902294.
Dulvy, N.K., Ellis, J.R. & Armstrong, A.O. 2024. Rajella kukujevi. The IUCN Red List of Threatened Species 2024: e.T161622A124516905.
Ebert, D.A. and Stehmann, M.F.W. (2013) Sharks, batoids, and chimaeras of the North Atlantic. FAO Species Catalogue for Fishery Purposes. No. 7. Rome: Food and Agricultural Organization of the United Nations (FAO).
ICES (2024). Report of the Working Group on Elasmobranch Fishes (WGEF). ICES Scientific Reports. 06:75. 994 pp. https://doi.org/10.17895/ices.pub.26935504.
Iglésias, S.P. 2012. Chondrichthyans from the North-eastern Atlantic and the Mediterranean (A natural classification based on collection specimens). Provisional version 06, 01.04.2012.
Rodríguez-Cabello, C. et al., (2012) ‘New records expand the known southern most range of Rajella kukujevi (Elasmobranchii, Rajidae) in the North-Eastern Atlantic (Cantabrian Sea)’, Journal of Applied Ichthyology, 28(4), pp. 633–636. doi: 10.1111/j.1439-0426.2012.01935.x.
