Aspects of population structure of nacella concinna (Strebel, 1908) (Gastropoda Nacellidae) at Admiralty Bay, King George Island, Antarctica

Antarctic intertidal zones are extremely stressful environments, and the Antarctic limpet Nacella concinna is one of the most conspicuous components of the megafauna, colonizing these areas at Admiralty Bay. This species has the potential to be a biomonitor, since it suffers the direct effects of environmental variations and anthropic impacts. In the summer 2010, specimens of N. concinna were collected at 6 sites in Admiralty Bay, in order to investigate population variability. Most individuals were larger than 20 mm, with positive allometric growth. Females were smaller and usually outnumbered males in the population. The preliminary results showed that limpets near the Brazilian station did not present any atypical values, so it seems that human activities do not significantly affect the population structure. Differences found should be considered a response to natural physical or biological factors.