Reproductive areas and thermal niche of arctic skate (Amblyraja hyperborea) in Icelandic waters

The Arctic skate Amblyraja hyperborea is a widely distributed cold-adapted deep-water elasmobranch whose reproductive habitats remain poorly documented. Using long-term Icelandic groundfish survey data (1996-2024), spatially persistent reproductive areas were identified based on repeated co-occurrence of egg capsules, juvenile and reproductively active females. Juveniles and active females were infrequently observed; however, their consistent spatial overlap with egg capsules revealed several potential reproductive areas along the northern and north-eastern Icelandic shelf break. Environmental analysis indicated narrow thermal niche, with most individuals occurring between -3 and 0.3 °C (stenothermal index = 2.0 °C), while egg capsules were associated with an even more restricted temperature range and occurred at shallower depths than adults. These findings suggest that reproductive sites of Arctic skate could be constrained by environmental conditions and may be particularly vulnerable to ongoing changes in deep-water temperatures regimes in high-latitude marine ecosystems.