Spatial overlap of two sympatric species (Raja clavata, Rostroraja alba) and its relationship with their diets

This study investigates the spatial overlap between two sympatric species Raja clavata and Rostroraja alba within a Marine Protected Area: Luis Saldanha Marine Park in Portugal. Through spatial analysis, a consistent and strong spatial overlap between the two species’ home range area was identified. This strong spatial overlap remains present all day long with no significant variations between daytime and nighttime. Suggesting a daily shared area of activity between the two species. This strong overlap persists all year round with a slight decrease during a yearly two-month period. Spatial overlap at nighttime could lead to potential interspecies competition. Both species exhibit similar bony fish diets, as indicated by environmental DNA (eDNA) analysis, with a notable abundance of fishes from the Clupeidae family. Raja clavata primarily consumes Clupeidae fishes, while Rostroraja alba displays a broader diet, including non-Clupeidae species alongside Clupeidae prey. A significant spatial overlap and shared diet may hint at interspecies competition, but further inquiry is required on prey availability and inter-species interactions. Overall, this study offers a first insight into the spatial dynamics and dietary habits of these sympatric species within a protected area, highlighting potential implications for their fitness and suggesting potential opportunities for future conservation strategies.