Sharks and Skates of Scotland Report: Longnosed skate (Dipturus oxyrinchus)

Scotland and Northeast Atlantic: Decreasing (Finucci et al., 2024). Overall population trend unknown due to limited data; however, Dipturus oxyrinchus is suspected to have declined by nearly 30% over the past 30 years (three-generation span) (Ellis et al., 2015). Possible signs of increases in biomass and numbers in the Norwegian coastal waters (ICES 2024).  

Global: decreasing. a global population reduction of 30–49% was suspected over three generation lengths (45 years) based on abundance data and actual levels of exploitation (Finucci et al., 2024). 

Conservation listings

• IUCN Red List Global: Vulnerable (assessment 20 April 2023)
• IUCN Red List Mediterranean: Near threatened (assessment 25 March 2016)
• CITES: Not listed
• CMS: Not listed
• OSPAR: Not listed

Range and distribution 

There are two genetically distinct populations of Longnosed skate, one in the Northeast Atlantic and the other in the Mediterranean (Ellis et al., 2015). It is estimated that these populations separated 20,000 years ago (Griffiths et al., 2011). In the Northeast Atlantic the species has historically been recorded northwards from the Canaries, Madeira and Northern Morocco up to the Faroes, Shetland, central Norway, the northern part of the North Sea and Skagerrak. However, both the range and abundance of the skate are suspected to have reduced in the Northeast Atlantic subpopulation, and it is not common in UK waters. CEFAS research vessel survey data from the 1960s – 2002 found that Longnosed skate was absent from inshore waters of England and Wales, whereas they were recorded occasionally in Scottish waters in depths of 111–159 m. The species are known to occur in small but stable numbers on the Rockall Bank (UK-Scotland surveys) (Clarke et al., 2016). Longnosed skate is thought to be locally extinct in the Irish Sea; however, this is disputed by some who believe it was not historically present in Irish waters (Clarke et al., 2016). Surveys along the coast of Norway indicate that the species is relatively rare but may aggregate in certain areas. Data from the Bay of Biscay show large fluctuations in abundance over a decade (from 1999 to 2010).  

Habitat 

Longnosed skate are found over sandy and muddy seabed habitats at depths ranging from 70-1230 m down the continental slopes of the Northeast Atlantic, in both shelf and deep-sea habitats (Clarke et al., 2016; Ellis et al., 2015; Finucci et al 2024). In the Mediterranean, the species is recorded most often at depths of 200-500 m, and it is moderately abundant in the central and eastern Mediterranean Sea but is no longer found in the western Mediterranean (e.g. Gulf of Lions and parts of the Adriatic Sea) (Ellis et al., 2015). 

Biology and Ecology

Longnosed skate are oviparous and lay eggs between February and May. Egg cases are 10-15 cm long, and newborns measure ~ 17cm total length (Ellis et al., 2015); however, the Mediterranean subpopulation is thought to be reproductively active throughout the year (Bellodi et al., 2017). Both males and females become sexually mature between 6-8 years old (Ellis et al., 2015), and a study from Sardinian waters estimated length at maturity to be 91.0 cm TL for males and 103.5 cm TL for females (Bellodi et al., 2017), whereas in the Aegean Sea males are reported to mature at 64-65 cm and females at 82-83 cm TL (Yıgın and Ismen, 2010). The maximum age recorded varies; for example, in Sardinian waters, the oldest females and males recorded are 17 and 15 years, respectively (Bellodi et al., 2017), whereas in Tunisian waters, the oldest male and females reported are 26 and 38 years, respectively (Kadri et al., 2015). Longnosed skate can reportedly reach a maximum length of 150 cm TL. Studies of gut contents in the Mediterranean found that the juvenile Longnosed skate mainly feed on crustaceans (e.g. mysids), while more mature individuals prefer to feed on crustaceans (e.g. decapods), fish and molluscs including cephalopods (Yıgın and Ismen, 2010; Mulas et al., 2015; Arcioni et al., 2025).  

Human interactions 

Longnosed skate are vulnerable to overexploitation and local extinction due to their large body size, slow growth rates and the time they take to reach sexual maturity (6-8 years). Most size classes of the species can be taken as bycatch in demersal trawl fisheries (as well as longline fisheries), especially in deeper offshore waters (Ellis et al., 2015). Longnosed skate are grouped under “other skates and rays” in ICES advice on catch, effort and fishing opportunities. They are included in the group of ‘other skates and rays’ in the ICES assessments. ICES was unable to provide any advice for the period 2024-2028 due to the lack of sufficient survey and catch data (ICES, 2023, 2024b).