A large skate with a distinctive tapered snout, the presence of which has been rarely recorded in Northern Irish wates.

In brief

• Large skate reaching up to 2.3 m, with distinctive tapering snout.
• Very rarely recorded in Northern Irish waters, but there have been some egg cases recorded (2020) that indicate potential presence here.
• Critically Endangered in an Irish and European context, Endangered in a global context.

Species description: A very large skate that can reach up to 2.3 m in length. The snout is very distinctive, tapering to a sharp point and covered with thorns and gives this species one of its common names - the bottlenose skate. It has a flattened grey to brown body with a lighter underside, the front edges of the body are concave with a sinuous outline.

Similar species: Could potentially be confused with other large skates (Dipturus spp.), however the distinctive snout should help differentiate.

How to see this species: Reported to prefer rockier habitats, found from 40 - 400 m. Occasionally deeper. Most records are from west coast of Ireland with a few scattered records elsewhere, some of which are washed up egg cases. Two egg cases recorded from north coast of Northern Ireland in 2020 suggesting it may be present in Northern Irish waters.

Current status: Critically endangered. Data deficient. Historically was once abundant enough to support a targeted fishery (19th century) but populations have undergone severe decline and are likely extirpated in parts of their former range.

Why is this species a priority in Northern Ireland?

• Criterion 1: Internationally listed species.
• Criterion 2: Decline based on available data and expert judgement.
• Criterion 3: Rare or restricted range – rare breeding species confined to 5 hectads or less (based on expert judgement).
• Criterion 4: NI stronghold or endemic – both stronghold range/population and designation as ‘endemic’ subject to expert judgement.

Threats: Previously this species was subject to targeted fisheries but populations have since collapsed and the main threat is now from bycatch, especially in areas where trawling or other forms of bottom fishing occur. Being a large species it is more prone to this due to large body size and relatively slow rate of maturing.

Action: Records of new sites for this species, including egg cases, with details of habitat and population are always valuable. Observations with a photograph can be recorded using iNaturalist, find the MBDP-NI iNaturalist project here.

Alternatively, records can be sent to CEDaR, National Museums Northern Ireland, 153 Bangor Road, Cultra, Holywood, County Down, BT18 0EU. Tel 028 9039 5257, e-mail cedar.records@nationalmuseumsni.org, or via the online portal.

Conservation:

• Listed as Critically Endangered on Irish and European Red List.
• Listed as Endangered on Global Red List.
• On OSPAR list of Threatened and/or Declining Species and Habitats.

Distribution Map from NBN: Rostroraja alba at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Rostroraja alba at iNaturalist World Species Observations database.

WoRMS: Rostroraja alba at World Register of Marine Species. Accepted name: Rostroraja alba (Lacepède, 1803). AphiaID: 105896.

Classification: Biota; Animalia; Chordata; Vertebrata; Gnathostomata; Chondrichthyes; Elasmobranchii; Neoselachii; Batoidea; Rajiformes; Rajidae; Rostroraja