Population biology of the sea star Anasterias minuta (Forcipulatida: Asteriidae) threatened by anthropogenic activities in rocky intertidal shores of San Matías Gulf, Patagonia, Argentina

ARRIBAS L.P.; BAGUR M.; PALOMO M.G.; BIGATTI G.

REVISTA DE BIOLOGíA TROPICAL

REVISTA DE BIOLOGIA TROPICAL

Lugar: Turrialba; Año: 2017 vol. 65 p. 73 - 84

0034-7744

In Patagonian coastal areas, intertidal benthic communities are exposed to extreme physical conditions. The interaction between harsh environment and anthropogenic pressure can generate changes in population biology as density and reproduction. The oral brooding sea star Anasterias minuta is a key organism in food chains of Patagonian rocky intertidals, hence changes on its population structure can negatively affect shore communities. We studied population biology of A. minuta (including density, biomass, size, reproduction season and feeding activity) and assess the effect of environmental parameters and anthropogenic activities on its population on rocky intertidal shores of San Matías Gulf, Patagonia, Argentina. Seasonal data of sea surface temperature, pH, salinity, water velocity, desiccation rate, boulders density, and anthropogenic influence (tourists and octopus fishermen) were recorded. There was significantly distinct spatial and seasonal variation in A. minuta population biology. In sites with less tourist influence and high refuge, an increase in A. minuta density was registered especially during summer. Also, A. minuta size showed differences among sites and seasons. Individuals in brooding period were found in austral fall and winter, while we observed individuals feeding in all seasons (12 different prey, mainly the molluscs Tegula patagonica and Perumytilus purpuratus). Environmental variables as boulders density and water velocity were the most important predictor of variation in A. minuta population structure. Further, tourist influence and pH were the most important variable negatively correlated with A. minuta density. Future changes in the population of A. minuta due to variations in environmental conditions and increase anthropogenic influence could affect biodiversity throughout the North Patagonian coast.