Abstract

Community structure of pelagic copepods inhabiting the coastal upwelling zone of central-southern Chile was compared between the periods 2002-2004 and 2010-2012. For both periods, 74 copepod species were identified; the Order Calanoida accounted for 68% of the total abundance. Numerically dominant species (ca. 80% of total abundance) were Paracalanus cf. indicus, Oithona similis, Calanoides patagoniensis, Drepanopus forcipatus and Acartia tonsa. Multivariate analyses showed that from the first period (2002-2004) to the second period (2010-2012), there were significant changes in the abundance of some species, the order of dominance and community size structure, although no significant changes in species richness and diversity indexes were found. The dominant species, Paracalanus cf. indicus, was numerically replaced by Drepanopus forcipatus in 2010-2012. There was also a significant decrease in total abundance of copepods during 2010-2012. The assessment of oceanographic variables revealed that colder and saltier conditions prevailed during 2010-2012, accompanied by a greater stratification of the water column because of increased upwelling intensity. Our findings suggest that increasing upwelling has been an important factor for causing changes in the copepod community structure during the past decade.