Cuckoo ray

How it lives

It lays eggs in small rounded capsules, 5 to 7 cm long, which wash ashore as mermaid's purses. The number of eggs is uncertain: up to about 100 egg cases a year in Wikipedia, 70 to 150 eggs a year in FishBase, and about 63 eggs per female per year in Portuguese waters. In that study spawning ran all year with a winter peak, and the size at maturity was about 56 cm. Wikipedia gives maturity at about 7.4 years for females and 6.8 years for males. The Wildlife Trusts say it lives about 8 years, so lifespan is unclear. It lives on sand, rock and cobbles, mostly at 50 to 200 m, and in a range of 10 to 900 m.

Where it goes

The Wildlife Trusts say young rays prefer deeper offshore water while adults gather closer to shore. I did not find tracking data in the sources I opened.

We only draw a journey on the map when scientists have tracked it or clearly documented it. For this animal we have not found one yet.

Populations

IUCN Near Threatened; FishBase gives the assessment date as February 2024. It lives in the eastern Atlantic from the Kattegat and North Sea around Great Britain and Ireland to the Mediterranean, Morocco and Senegal. The Wildlife Trusts list it as Least Concern globally and Vulnerable in Ireland, but the Red List lookup and FishBase both give Near Threatened. Commercial fisheries catch it only in minor amounts and it is vulnerable where fishing is heavy. I did not find a total population count.