Common skate photo-identification database for Scotland
Common or flapper skate (Dipturus cf. intermedia), the largest of European skates, was once a common component of benthic fish communities throughout northwestern Europe but has been extirpated from most of its range due to overfishing. The species has accordingly been classified as ‘Critically Endangered’ on the IUCN Red List.
Argyll harbours one of very few remaining relict populations of this species in UK coastal waters, where it is subject to a recreational catch-and-release fishery.
An active community of sea anglers and local skippers have been gathering tagging data on these fish for decades, which contributed to the 2016 establishment of the ‘Loch Sunart to the Sound of Jura’ Marine Protected Area (MPA) for this species.
Scottish Natural Heritage (SNH) is currently seeking appropriate long-term monitoring solutions to evaluate the effectiveness of this MPA and answer broader questions about skate abundance, distribution, movement and life history for management purposes in a wider Scottish context.
Skates have distinctive spot patterns on their dorsal surfaces which allow individuals to be reliably identified over periods of at least 4 years (manuscript in prep.). Recaptures of the same individuals are also a common occurrence. Skippers and sea anglers regularly collect photographs of caught skates, and numbers of photographed skates exceed numbers receiving physical tags. This offers the prospect of developing a long-term photo-identification database for common skate on the basis of photographs taken by members of the public (particularly recreational sea anglers and skippers).
The main project aim is to develop a photo-ID library for flapper skates on the basis of current and historic photographs submitted by members of the public. This will contain records of initial capture and each subsequent recapture over the timescale covered by the photos received.
This photo-ID library will
- complement current ongoing tagging efforts by SNH within the MPA
- allow integration of historic observations of skates by members of the public, and
- potentially extend monitoring efforts into areas where tagging isn't currently taking place.
As such, the photo-ID library is intended to contribute to management of flapper skates within and outwith the recently established ‘Loch Sunart to the Sound of Jura’ MPA.
Role of SAMS
Dr. Steven Benjamins is involved in matching submitted photographs, maintaining the photo-ID library and analyzing the resulting data in collaboration with SNH. An undergraduate final year dissertation project further supports this project, aiming to further determine the long-term stability of skate pigmentation patterns and scar tissue regeneration.