Drivers of spatial behaviour of the endangered undulate skate, Raja undulata

Knowledge of the spatial behaviour of aquatic living resources is essential to assess their vulnerability to environmental and anthropogenic stressors and inform efficient management strategies. Elasmobranchs are particularly vulnerable to exploitation. Within this group of fish, the implementation of species-specific conservation actions has been challenging due to insufficient information on their biology and ecology. In this study, acoustic telemetry was used to investigate the seasonal variation, diel patterns, and biological and sea temperature effects on the spatial behaviour of the endangered undulate skate, Raja undulata, within a marine protected area in north-west Spain. Movement and behaviour were mainly driven by diel and seasonal patterns. The presence of the tagged skates in the study area peaked during summer. Space use was highest in late spring and activity was lowest during summer. Skates used more space and were more active during night-time as compared to daytime, when they stayed in sandy bottoms. Sea temperature had a negligible positive effect on activity. Our work represents an important contribution to the understanding of the ecology of this endangered, yet commercially important skate in Europe, and provides important insights for the implementation of spatial and temporal restrictions aimed at reducing mortality and bycatch of this species.

Automated summary

The study revealed that the spatial behavior of the undulate skate is mainly driven by seasonal and diel patterns, with peak presence in summer, highest space use in late spring, and lowest activity in summer. The skates were more active during night-time and stayed in sandy bottoms during the daytime. Sea temperature had a negligible positive effect on their activity.