Pseudo-nitzschia multistriata (Bacillariophyceae) in New Zealand

Pseudo-nitzschia multistriata (Takano) Takano has been observed in seawater samples from the North Island and from the northern waters of the South Is land, New Zealand, with blooms of >1.0 x 10(6) cells litre(-1) being record ed in December 1997 (austral summer), and minor blooms occurring in both su mmer and winter 1998 and 1999. The species is notable for its sigmoid form, and for its crossreactivity with oligonucleotide probes targeted at P. aus tralis Frenguelli ribosomal RNA. The species is non-toxic, and for biotoxin monitoring purposes needs to be discriminated from the highly toxic P. aus tralis. It falls in the "delicatissima" complex of Pseudo-nitzschia H. Pera gallo species, and electron microscopy shows a close resemblance to P. deli catissima (Cleve) Heidin, except for the lack of a central larger interspac e.