[11] The blue skate was first formally described as Raja batis in the 10th edition of Systema Naturae by Carl Linnaeus published in 1758 with its type locality given as "European Seas, locations being given as England and Lesbos.
[14] Distinct genetic and morphological differences exist within the common skate as traditionally defined, leading to the recommendation of splitting it into two species: The smaller (up to about 1.45 m or 4.8 ft in length) southern D. cf.
[11] A formal request of preserving the name D. batis (with flossada as a synonym) for the blue skate has been submitted to the International Commission on Zoological Nomenclature, but as of 2017 a decision is still pending.
intermedius has dark olive-green eyes and the blotch on each wing consists of a group of pale spots.
flossada based mainly on the ICES International Bottom Trawl Survey and zoological specimens,[19] the species off Norway is D. cf.
flossada, but it might occur),[17][20] and based on limited data the main in the North Sea, Skagerrak and Kattegat is D. cf.
[19][21] Uncertainty exists about the exact species involved in the southern half of the range, but a preliminary morphological study indicates that the one in the Azores is D. cf.
[24] The top surface is generally coloured olive-grey to brown, often with a pattern of spots, and the underside is lighter blue-grey.
[2] Its presence in the Mediterranean Sea is questionable since earlier records could concern D. intermedius recently considered as a distinct species.
They mate in the spring, and during the summer, females lay about 40 egg cases in sandy or muddy flats.
In the 19th and 20th centuries, egg cases were seen along the entire British coastline in high numbers, but now they are found only in a few areas.
Its diet consists of crustaceans, clams, oysters, snails, bristle worms, cephalopods, and small to medium-sized fish (such as sand eel, flatfish, monkfish, catsharks, spurdog, and other skates).
[15] The blue skate is listed as a critically endangered species by the IUCN and it is threatened both in the Atlantic Ocean and Mediterranean Sea.
[1] The blue skate's population has drastically decreased because of overfishing and it likely will disappear entirely unless more is done to preserve it.
[4][16] A stronghold along the coast of Norway has been suggested,[4] but recent studies indicate the species is rare there and many previous records are the result of misidentifications of other skates.
[34] The blue skate is strictly protected within the EU, making it illegal for commercial fishers to actively fish for it or keep it if accidentally landed.