Influence of environmental variables on Alexandrium catenella motile stage and other harmful taxa in southern Chile (43° - 55° S) (January - December 2009).

Phytoplankton records during the last decade in Southern Chile (41o-55o S) show that Alexandrium catenella blooms are recurrent, have an annual frequency in the area between 43o50’ and 55o00’, but sporadic (2002, 2006 y 2009) between latitudes 42o20’and 43o20’. These blooms are always associated with the presence of Paralytic Shellfish Poison (PSP) in molluscs. The temporal and geographical distribution by A. catenella during each event seems to be associated with the characteristics of different sectors of the study area. Remarkable hydrographic and meteorological differences occur in this vast geographical area. Based on biological, toxicological, hydrographic and meteorological information generated during 2009, the structure and interrelationships of recorded variables are analyzed to identify key variables linked to A. catenella blooms, which will serve to generate explanatory models for these phenomena.