Prorocentrum redfeldii Bursa 1959
P. pyrenoideum Bursa 1959
Morphological Characteristics :
Cell rounded at the anterior end and pointed at the posterior end. The cell is distinguished from P. sigmoides by its much smaller body size. The length is twice as long as width. Nucleus in round shape, normally at the posterior end. Thecal plate with scattered trichocyst pores.
Size of Specimen :
20-25 mm (L), 10-12 mm (W)
Distribution :
Recorded in Plymouth, UK; Adriatic; Mediterranean; W. coast of Africa and Japanese waters. A very common species in Tolo Harbour, Hong Kong. Caused numerous red tides in Hong Kong in the late eighties.
Major Limiting Factors :
Dissolved inorganic phosphates, low N:P atomic ratio (8-15), blooms correlated with rainfall and freshwater input.
Toxicity :
Non-toxic; caused fishkills by oxygen depletion.