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.