April 2026 was a good month for mermaid’s purses on beaches along the west coast of Assynt. They are the empty eggcases of skates, rays and their smaller relatives.
On 19th, Anne Nicoll found four of the largest ones on a beach at Raffin (NC0131). They were those of the flapper skate Dipturus intermedia (photo 1); magnificent objects, up to 22 x 8 cm, whose black skins are largely covered with a coating of fine golden fibrils.
A few days later, on 28th, Andy Summers had a further three flapper skate eggcases a little further south, at Balchladich (NC0230). There was also a smaller black eggcase, probably that of a thornback ray Raja clavata, and an even smaller yellowish eggcase, with tendrils, of the small-spotted catshark Scyliorhinus canicula (photo 2).
Skates
Skates are the largest members of their family of elasmobranch fish, with cartilaginous skeletons, to which group catsharks and sharks also belong.
Flapper skates are huge, up to 250 cm in length. Found in the northern North Sea and off the coast of North-west Scotland, they are sometimes reported from sea lochs, but occur down to a depth of 900m. They feed on larger crustaceans and other fish, including their smaller relations.
Blue skates Dipturus batis are smaller, up to 143 cm in length. They have only recently been recognised as genetically distinct from flappers, and appear to be much rarer in shallow waters, inhabiting the Celtic Sea (to the west of the British Isles) and areas around the Rockall Bank.
Their eggcases are rarely found, but one was spotted by Gwen Richards on a seaweed-covered boulder in Lochinver Harbour, just south of the Church of Scotland (NC0922), during a Dead Bird Beach Survey on 26th February 2022 (photo 3). It is smaller than that of the flapper skate (photo 4), about 15 x 4.5 cm, covered with a buff-coloured finely-fibrillose coating and with long tassels from the open end.
Both skates are classed as Critically Endangered owing to relentless over-fishing in the past and it is good to find evidence of some recovery in local populations in the form of their eggcases.
Ian M. Evans