Resurvey of sea urchins and mussels at protected and harvested shores a decade after: A beyond-BACI approach.

Comparing temporal patterns of distribution and abundance of target organisms between protected and harvested shores is essential to assess the extant effectiveness of marine protected areas (MPAs) and whether it is maintained through time. By means of an adapted Beyond-BACI approach, we compared the short- and long-term patterns of variation in the abundance of the sea urchin Paracentrotus lividus and the mussel Mytilus galloprovincialis at a protected shore (within the Parque Litoral Norte MPA, Portugal) and at three adjacent shores subject to intense harvesting over a decadal interval. Despite the existence of the MPA for more than 30 years, we did not obtain clear evidence of its persistent or recent effectiveness on intertidal species of commercial interest.