Drivers of behaviour and movement patterns of the endangered undulate ray, Raja undulata

Katharina Leeb

Spatial ecology and behaviour of a species is essential to assess its vulnerability to environmental and anthropogenic stressors and consequently develop efficiency management strategies. Elasmobranchs, as k-strategy species are particularly vulnerable to exploitation, especially in coastal areas. Species-specific conservation management has proven to be challenging, due to insufficient information on their biology and ecology. In this study we used a VPS acoustic telemetry array to identify biological and environmental drivers for presence, space use and activity of the endangered undulate ray, Raja undulata, within an MPA in the southern Galician coast (NW Spain). Movement and behaviour were mainly driven by diel and seasonal patterns, activity levels differed between sexes and temperature and upwelling conditions were less important drivers for behaviour. No effect of body size was observed. While the presence in the study area and home range size decreased from summer to autumn, activity increased towards mid-September and followed a clear diel cycle with nocturnal activity peaks. We hypothesised that foraging and reproduction are likely to be the main underlying biological drivers. 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 management strategies.