First assessment of the rocky intertidal communities of Fildes Bay, King George Island (South Shetland Islands, Antarctica).

Studies on Antarctic intertidal fauna are comparatively scarce compared to those from the sublittoral and the deep sea. In order to contribute to filling this gap in knowledge, during the 2006 BENTART Spanish Antarctic Expedition, we conducted a quantitative and qualitative study on the fauna inhabiting the intertidal rocky platform of Fildes (=Maxwell) Bay, King George Island (South Shetlands Archipelago). This platform is dominated in its middle and lower area by the brown algae Adenocystis utricularis, which covers ca. 100 % of the rocky surface. Three quantitative samples of 20 × 20 cm were taken in the community of A. utricularis, and one additional sample of 20 × 20 cm in the tide pools community dominated by the gigartinacean rhodophyceae Iridaea cordata. In addition, qualitative samples of invertebrates that live under the boulders were also taken. Quantitative samples yielded a total of 9950 individuals belonging to 41 species. Mollusks were the most abundant group with a total of 9522 specimens belonging to 11 species, being the gastropod Eatoniella kerguelenensis regularis the most abundant with 6763 specimens. Crustaceans were represented by 295 specimens and 7 species and annelid polychaetes with 133 specimens and 20 taxa. The Shannon diversity indexes calculated for the quantitative samples of A. utricularis ranged between 0.803 and 1.030 with values of 1.577 for the I. cordata community. Our study confirms that the intertidal area of Fildes Bay hosts a surprisingly rich community in terms of abundance and biodiversity. [ABSTRACT FROM AUTHOR]