Antarctic sea anemone distribution, abundance and relationships with habitat composition, community structure and anthropogenic disturbance

Understanding the distribution, abundance and habitat preferences of species in the Southern Ocean provides a foundation for assessing the impacts of environmental change and anthropogenic disturbance on Antarctic ecosystems. In near-shore waters at Casey and Davis Stations, photoquadrat surveys were used to determine sea anemone distribution and abundance, habitat preferences, associations with other species and the impact of human disturbance on sea anemone distribution. Two distinct sea anemone morphotypes were found in this study: large sea anemones that require hard substrate for attachment and small, burrowing sea anemones found in muddy sediment. The large sea anemones were found in rocky habitats, with the exception of some sedimentary habitats where other biota were used as substrate. The large sea anemones were associated with a diverse community of epibenthic species found in rocky habitats. The burrowing sea anemones were associated with a less diverse assemblage of sediment-dwelling epibenthos. At Casey Station, sea anemones were more abundant in habitats adjacent to a former waste disposal site than at control sites. The reason for this is not yet known, but may be due to high organic matter inputs or, alternatively, a longer sea ice duration providing protection from ice scour.