Harmful phytoplankton in the Beagle Channel (South America) as a potential threat to aquaculture activities

Abstract

The Beagle Channel is a remote subantarctic environment where mussel aquaculture initiatives have existedsince the early 1990s. Here we analyze phytoplankton biomass and composition, and the occurrence of harmfulmicroalgae species and their toxins at three sites during the period 2015?2016. The occurrence of potentiallyharmful algae was observed throughout the study period, including toxigenic dinoflagellates such asAlexandrium catenella (Group I of the A. tamarense complex), A. ostenfeldii, Dinophysis acuminata, Gonyaulaxspinifera, Azadinium sp., and the diatoms Pseudo-nitzschia australis and P. fraudulenta. Toxic dinoflagellates weredetected in low densities whereas a Pseudo-nitzschia bloom was observed in late February. Isolates of A. catenellaand P. delicatissima sensu stricto were phylogenetically characterized. The toxin profile of A. catenella wasdominated by GTX4, while P. delicatissima sensu stricto showed no production of the neurotoxin domoic acid inculture conditions. The results provide base-line information for the management of harmful algal blooms in thislittle explored subantarctic area.