Resumo

CANETE, Juan I; ASTORGA, María S; SANTANA, Mario  e  PALACIOS, Mauricio. ABUNDANCE AND SPATIAL DISTRIBUTION OF SCOLECOLEPIDES UNCINATUS BLAKE, 1983 (POLYCHAETA: SPIONIDAE) AND SEDIMENTOLOGICAL CHARACTERISTICS FROM BAHÍA LOMAS, TIERRA DEL FUEGO, CHILE. Anales Instituto Patagonia (Chile) [online]. 2010, vol.38, n.2, pp. 81-94. ISSN 0718-686X.  doi: 10.4067/S0718-686X2010000200008.

This paper describes the spatial and seasonal dynamic of the population of the spionid polychaete Scolecolepides uncinatus Blake 1983 from a sandy-muddy intertidal located in an embayment with megatidal regime at Lomas Bay, Tierra del Fuego, Magellan Strait, Chile (52°40' S, 69°15' W). In order to test the trophic importance of this polychaete, the abundance and spatial distribution was studied in July-August, 2007 (winter; -2 °C) and January 2008 (summer; 17°C to 23 °C). At both seasons, three transects near to 2 km of length were sampled. The polychaete was present in both periods at all three transects showing high variations in abundance in accordance with the sediment type. The lowest abundance was detected in muddy bottoms during winter and summer (transect 3). At both seasonal sampling, the abundance of S. uncinatus was higher at transects 1 and 2 (mixture of sandy and muddy bottom) in winter (birds-absence) when compared to summer (birds-presence). In sandy bottoms, S. uncinatus forms aggregations of short tubes in the interface air-sand (4 to 5 cm) while in muddy bottoms, it builds solitary long-deep tubes and the specimens are found near to 25 cm depth, having a larger size (10 cm) compared to individuals found in sandy bottoms. The present work constitutes a new record of S. uncinata in the eastern entrance of the Magellan Strait.

Palavras-chave : Subantarctic benthos; RAMSAR Site N° 1430; Chilean Polychaeta; Inner Continental shelf; Calidris canutus; Magellan Strait.