SEASONAL CYCLE OF APPENDICULARIANS AT A COASTAL STATION (38°28´S, 57°41´ W) OF THE SW ATLANTIC OCEAN

CAPITANIO, F.; CURELOVICH, J.; TRESGUERRES, M; NEGRI, R; VIÑAS, M.; ESNAL, G.

BULLETIN OF MARINE SCIENCE

RSMAS

Lugar: Florida, USA; Año: 2008 vol. 82 p. 171 - 184

0007-4977

Temporal fluctuations in appendicularian species composition, abundance, size structure and  biomass, and their relationships with physical and biological factors were studied biweekly to monthly from March 2000 to April 2001 at a coastal station (38°28´S, 57°41´W) of Argentina, SW Atlantic Ocean. The highest abundances and biomasses were recorded during spring-summer with a maximum in early January (4369.2 ind.m-3= 2321.2 µgC.m-3). Secondary production was 76 mgC.m-3.y-1 and house production was 123 mgC.m-3.y-1. Fritillaria borealis (Lohmann 1896) was coupled to temperature changes, being more abundant during fall-winter; however, low biomasses were registered. Appendicularia sicula (Fol 1874) and O. fusiformis (Fol 1872) appeared during summer and autumn, but their abundance was low. Oikopleura dioica (Fol 1872) was present all year round and was the dominant species. When chlorophyll a concentration was high, and copepod abundance was low (fall-winter period), both juvenile and adult animals of O. dioica were abundant in all the samples. During the spring-summer period (low chlorophyll a concentration) a high predominance of adult animals (up to 1400 µm TL) was observed, suggesting a strong predation by copepods upon O. dioica eggs and juveniles. However, further field evidence would be necessary to support this conclusion.