Differences in mussel beds of Nuevo Gulf (Patagonia, Argentina) in locations with contrasting wave energy.

PONTONES, JULIÁN; CARRASCO, MAURO F.; CRESPI ABRIL, AUGUSTO CÉSAR

México D.F.

Congreso; Mollusca 2014: encuentro de las américas; 2014

Wave energy is an important factor that controls rocky intertidal communities in Northern Patagonian coasts. In this study, we selected 3 abrasion platform headlands in Nuevo Gulf, Punta Pardelas (PP), Punta Este (PE) and Cerro Avanzado (CA), based on the results of modeling the wave energy produced by winds. Wave energy was modeled using the WEMo software and the mean energy of each site was estimated from 10 points separate 100 from each one. In each rocky intertidal, six samples of mussel beds were collected from a 10x10cm surface to estimate relative abundance and mean size of individuals. The mean wave energy was higher for PP (4950 J/m) followed by CA (1580 J/m) and PE (925 J/m). The mean size of individuals was significantly higher in PP (16.44mm) than in PE (12.93mm) and CA (12.37mm), whilst the relative abundance was significantly lower in PP (21800 ind/m2) than in PE (38400 ind/m2) and CA (47780 ind/m2). The differences in size observed between the different sites reflects the phenotypic plasticity of mussels under the influence of environment. Sites with low densities may favor individual growth of mussels by releasing competition among them allowing that individuals in high energetic locations reach higher sizes.