Ecological role, fishing impact, and management options for the recovery of a Mediterranean endemic skate by means of food web models

The Mediterranean endemic starry ray (Raja asterias) is one of the few demersal skates that are still present in Mediterranean exploited ecosystems. However, this species has declined with time, its presence in survey data is scarce, and limited information is available about its ecology and the impact of fishing on its populations. We examined key ecological features of this species such as reproduction, trophic behaviour and growth. We assessed the ecological role of this species within the food web using an ecological model of a North-Western Mediterranean ecosystem and setting the new information in an ecosystem context. We then explored impacts of fishing on the starry ray population using a dynamic temporal model and we developed fishing scenarios aiming at recovering the species. Field and modelling results showed that the starry ray is a potentially ecologically important predator of the Mediterranean demersal ecosystems, but its ecological importance in the food web is moderate-low since it is present at a low abundance. Results confirmed that the species has been and still is highly impacted by fishing and it is very sensitive to increasing fishing impacts. However, alternative fishing scenarios showed that Mediterranean starry ray populations may respond under decreasing trawl fishing effort and could substantially recover. The recovery of the starry ray may be accompanied by recovery of other demersal species and could have wider ecosystem impacts. Therefore, this skate could be a good sentinel species to indicate ecosystem health in current Mediterranean Sea ecosystems. These new insights may be useful to ensure the recovery and conservation of this species while triggering the recovery of exploited marine communities in the Mediterranean Sea.

► Field and modelling results are used to assess the ecological role of a Mediterranean endemic skate.
► The skate is an important predator but shows moderate-low ecological importance due to low abundance.
► The species has been highly impacted by fishing and it is sensitive to increasing fishing impacts.
► Simulations show the skate could substantially recover if trawl fishing effort decreases.
► This may be a good sentinel species to indicate ecosystem health in Mediterranean Sea ecosystems.