We present the results of conservation assessment of a rocky shore in the Central Pacific of Costa Rica (Playa Hermosa-Punta Mala National Wildlife Refuge) using the biological indicators proposed by the national environmental ministry. This study aims to analyze the influence of surveillance, between two sites, over the rocky shore habitat. The sampling was carried out during both the dry and rainy seasons in 2015. Our data shows that Nerita scabricosta -harvested in small-scale fisheries- presents a high number of colonies formed by few individuals. Moreover, the abundance varied between seasons, probably due to a storm surge. Macroalgae differed slightly among sites, where turf had higher percentage coverage in low surveillance areas, while brown algae had higher coverage in high surveillance areas. Mechanical damage (abrasion due to rocks overturning) associated with tourism and harvesting could be influencing the low surveillance area, explaining these differences. Macroalgae presented a seasonal change, probably related to the storm surge. The density of the Tetraclita stalactifera did not exhibit variations. The surveillance level and enforcement influenced some bioindicators of the rocky shore, and therefore could be used to assess the extractive pressure.

Keywords: bioindicator, Costa Rican coastal zone, intertidal macroalgae, marine protected area, Nerita scabricosta, Punta Mala, Tetraclita stalactifera