Occurrence of species from the genus Pseudo-nitzschia peragallo in Irish waters

The presence of potentially toxic diatom species from the genus Pseudo-nitzschia was investigated using net material acquired during several research surveys carried out off the southern, south-western and western coasts of Ireland between 1993 and 1997. Qualitative examination of the phytoplankton net samples using electron microscopy showed that P. pungens, P. multiseries, P. fraudulenta, P. australis, P. delicatissima and P. pseudodelicatissima were regularly present. Two other Pseudo-nitzschia species, tentatively identified as P. seriata (two forms: P. seriata f. seriata and P. seriata f. obtusa) and P. subpacifica, were also observed, though less frequently. Pseudo-nitzschia pungens was relatively abundant in August 1993 and July 1996. Pseudo-nitzschia fraudulenta was a common component in net samples examined throughout the survey and was predominant in the Pseudo-nitzschia flora in October 1997. Pseudo-nitzschia pseudodelicatissima and P. delicatissima were predominant in many of the net samples taken in July and September 1996.