Drivers of behaviour and spatial ecology of the small spotted catshark ( Scyliorhinus canicula )

Shark populations have suffered dramatic declines across the world as a result of overfishing.Marine protected areas (MPAs) can help restore overfished populations; however, their effectiveness largely relies on understanding the ecology of the targeted species.This study investigated the spatial ecology of the intensely harvested but understudied small spotted catshark (Scyliorhinus canicula) through acoustic telemetry in the Cies Islands, a small MPA in the north-west of the Iberian Peninsula.There were significant effects of diel, seasonal cycles, biotic (sex and total length) and abiotic (bottom sea temperature) variables on the spatial behaviour of S. canicula. The mean residency index was low (0.27) and movement patterns suggested a strong connection with inshore waters. While the probability of presence in the study area was mainly driven by sex (i.e. greater for females), a drastic increase in activity was observed at night (compared with daytime hours). The activity space decreased with larger body sizes. Warmer waters were related to higher activity levels and larger activity spaces.This study provides essential knowledge of the spatial behaviour of S. canicula, with significant implications for the conservation and management of this species. The results indicate that small MPAs may fail to protect the whole range of movements of S. canicula, but suggest a larger protection potential for females.To be effective for S. canicula conservation, MPAs should be appropriately sized and designed for the ranging behaviour of the target species in order to provide total protection. Temporal restrictions on fishing at night mirroring the peak activity pattern of S. canicula could be implemented to limit the probability of its capture.