Occurrence of harmful algae in an oligotrophic area of the Mediterranean Sea (Channel of Otranto).

The Southern Adriatic Sea has been so far immune from harmful algal bloom. However, in order to assess the risk of such an event, a phytoplankton monitoring was carried out with special attention to potentially toxic species. A total of 253 algal taxa were identified 18 of which were regarded as harmful, noxious, or toxin-producers. Seasonal changes of these potentially toxic populations are presented in relation to hydrographic and biotic factors. Ecological implications arising from the data are discussed on the basis of statistical analyses.