Sharks and Skates of Scotland Report: Blonde skate (Raja brachyura)

Population status

Scotland and Northeast Atlantic: Stable. Trend analysis of the North Atlantic modelled biomass for 1950–2021 (71 years) revealed annual rates of increase of 1.23%, with the highest probability of no major reductions in population over the past three generation lengths (29 years) (Finucci et al., 2024).  

Global: Decreasing. Due to increasing trends in parts of its range and inferred declines in others, and high levels of exploitation, a population reduction of 20–29% over the past three generations (29 years) was estimated (Finucci et al., 2024). 

Conservation listings

• IUCN Red List Global: Near Threatened (assessment 15 April 2023)
• IUCN Red List Europe: Near Threatened (assessment 13 May 2014)
• IUCN Red List Mediterranean: Near Threatened (assessment 25 March 2016) 
• CITES: Not listed
• CMS: Not listed
• OSPAR: Not listed

Range and distribution 

Blonde skate are a wide-ranging species that are found across much of the central and north-eastern Atlantic, from the waters of Morocco and Madeira in the south up to Shetland in the North. They are found in varying abundances around the British Isles (McCully-Phillips et al., 2015). The skate tends to be locally abundant in areas associated with their preferred habitat (sand banks), such as within the English Channel and Irish Sea, Bristol Channel and St George’s Channel in SE Ireland. They are less abundant in areas of the North Sea (at the edge of their geographical range) and their distribution is patchy in the Celtic Seas (Ellis et al., 2005). The species also occurs in the Mediterranean but is relatively rare when compared to the Northeast Atlantic. 

Habitat 

Blonde skate occur on the continental shelf at depths from nearshore to 150 m, and occasionally to 900m (Ellis et al. 2015, Last et al. 2016, Ebert and Dando 2021). They prefer sandbanks and usually occur in inshore waters at depths of 14–146 m in the Northeast Atlantic (Ellis et al., 2005). Shallower waters in this depth range may be used as nursery areas by juveniles (Ellis et al., 2005). The population across the Northeast Atlantic is suspected to be fragmented due to the species preference for sandbanks. Recapture studies have shown that blonde rays exhibit site fidelity (Simpson, 2018; Ellis et al., 2011). 

Biology and Ecology

Blonde skate have relatively large body size, reaching a maximum total length (TL) of ~120 cm. Male and female maturity occurs at 78 and 86 cm TL, respectively (McCully et al. 2012), and size-at-hatching occurs at 16–18 cm TL (Last et al. 2016). Reproduction is oviparous. Accurate fecundity estimates are lacking, but it is thought to be in the range of 37–90 eggs per year (Holden et al. 1971, Porcu et al. 2015), with a gestation period of up to 7 months (Stehmann and Bürkel, 1984; Ebert and Stehmann, 2013). Female age-at-maturity is 6 years and maximum age is 10–16 years (Fahy 1989, Gallagher et al. 2005, Porcu et al. 2015), resulting in a generation length of 9.5 years. Immature individuals remain in shallower depths before migrating to deeper habitats as adults (Simpson, 2018; Ellis et al., 2005). 

Human interactions