A holistic and comprehensive data approach validates the distribution of the critically endangered flapper skate (Dipturus intermedius)

Abstract

Morphological similarities between skates of the genus Dipturus in the north‐eastern Atlantic and Mediterranean have resulted in longstanding confusion, misidentification and misreporting. Current evidence indicates that the common skate is best explained as two species, the flapper skate (Dipturus intermedius) and the common blue skate (D. batis). However, some management and conservation initiatives developed prior to the separation continue to refer to common skate (as ‘D. batis’). This taxonomic uncertainty can lead to errors in estimating population viability, distribution range, and impact on fisheries management and conservation status. Here, we demonstrate how a concerted taxonomic approach, using molecular data and a combination of survey, angler and fisheries data, in addition to expert witness statements, can be used to build a higher resolution picture of the current distribution of D. intermedius. Collated data indicate that flapper skate has a more constrained distribution compared to the perceived distribution of the ‘common skate’, with most observations recorded from Norway and the western and northern seaboards of Ireland and Scotland, with occasional specimens from Portugal and the Azores. Overall, the revised spatial distribution of D. intermedius has significantly reduced the extant range of the species, indicating a possibly fragmented distribution range.

Northeast Atlantic elasmobranch community on the move: Functional reorganization in response to climate change

“…While in the Irish Sea, this is mainly attributed to the increased habitat suitability of S. stellaris , which is also the main species that led to the decrease in the mean latitudinal range of the communities, the dynamics are less clear in the Celtic and North Sea, where we can however reasonably attribute a strong effect of the presence of M. asterias . Since elasmobranchs have a slower pace of life compared to most teleost fishes, large‐bodied endemic species (e.g., D. intermedius , Garbett et al., 2023) are even more vulnerable to climate change (Jones & Cheung, 2018). Nonetheless, some species such as M. asterias may currently benefit from ongoing changes (Sguotti et al., 2016).…”

A Faunistic Revision of Longnose Skates of the Genus Dipturus (Rajiformes: Rajidae) from the Southern Southwestern Atlantic Ocean, Based on Morphological and Molecular Evidence

“…We acknowledge the ongoing need for more global detailed investigations of the large, brown, long-nosed skates. For example, the enigmatic case of Dipturus intermedius (Parnell, 1837), which exhibits a more confined, coastal distribution than previously assumed, despite the extensive history of research in the northeastern Atlantic, highlights the intricacies and challenges inherent to the taxonomy of these species [43]. Further comprehensive studies are imperative to enhance our understanding of the diversity and distribution of Dipturus and Dipturus-like taxa worldwide.…”