CONICET | Buscador de Institutos y Recursos Humanos

In Patagonian coastalareas, intertidal benthic communities are exposed to extreme physicalconditions. The interaction between harsh environment and anthropogenic pressurecan generate changes in population biology as density and reproduction. Thebrooding sea star Anasterias minuta isone of the key organisms in food chains of Patagonian rocky intertidal, hencechanges on its population structure can negatively affect shore communities. Westudied population biology of A. minuta(including density, size, biomass, reproduction season and feeding activity) andassess the effect of environmental parameters and anthropogenic activities on itspopulation on rocky intertidal shores of San Matías Gulf, Patagonia, Argentina.Seasonal data of sea surface temperature, pH, salinity, water velocity anddesiccation rate were recorded. Moreover, due to the existence of an iron mineand tourist recreational activities in the studied coastal area, human use ofeach sampling site was achieved. There was significantly distinct spatialvariation in A. minuta populationbiology. In sites with less tourist influence we registered an increase in A. minuta density during austral summer.As density, A. minuta size showeddifferences among sites, and both size and biomass presented seasonal variation.In austral fall and winter individuals were found in incubation period, and inall seasons individuals were observed feeding (12 different preys, mainly the molluscsTegula patagonica and Perumytilus purpuratus). Given the greatdiversity of consumed prey and the potential high predation pressure of A. minuta on rocky shore benthiccommunities, future changes in the population of asteroids due to changes inenvironmental conditions and increase tourism could affect biodiversitythroughout the North Patagonian coast.

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