Anales del Instituto de la Patagonia
On-line version ISSN 0718-686X
ALDEA, Cristian; ROSENFELD, Sebastián and CARDENAS, Javiera. Diversity characterization of subtidal benthic molluscs from Carlos III Island and adjacent areas, Strait of Magellan, Chile. Anales Instituto Patagonia (Chile) [online]. 2011, vol.39, n.2, pp. 73-89. ISSN 0718-686X. http://dx.doi.org/10.4067/S0718-686X2011000200006.
Despite the knowledge of marine benthic ecology in the Strait of Magellan, few studies have been focused on malacofauna. During April and June (2007), an extensive region on Carlos III Island and adjacent areas were studied under the project "Diagnosis of Macrobenthos in the Multiple-use Marine Protected Area Francisco Coloane". Subtidal benthic samples (5-20 m deep) were collected by means of SCUBA diving in 37 sites within quadrants of 0.25 m2. The fauna obtained was sieved, fxed and pre-served in ethanol. Molluscs were sorted, quantifed and identifed to species level. From data matrix the richness, abundance and diversity was evaluated, and analyzed the clustering and scaling in assemblages or groups, studying the common and preferential species, and those that most contribute to the similarity. From the 4,613 individuals studied, 101 species were identifed: 11 Polyplacophora, 59 Gastropoda and 31 Bivalvia. The most abundant species were the gastropod Margarella violacea (560 individuals) and the bivalve Neolepton yagan (389). The highest values of richness and abundance were recorded in the Brunswick Peninsula, while the highest values of diversity were presented in the Jerónimo Channel and Charles Islands. The stations clustering showed the presence of four significant assemblages with a similarity level >20%, not determining it a geographic pattern of organization. The gastropod Xymenopsis muriciformis contributed significantly to the assemblages similarity, while Trophon pallidus was present at all assemblages and the bivalve Aulacomya atra was the most presented species (17 stations). The high diversity and the obtained organization suggest considering abiotic parameters in future researches and a higher number of samples from adjacent areas.
Keywords : Marine Protected Area Francisco Coloane; Gastropoda; Bivalvia; Polyplacophora; ecology; benthos; assemblages.