The First Recorded Bloom of Pyrodinium Bahamense Var Bahamense Plate in Yemeni Coastal Waters off Red Sea, near Al Hodeida City

Özet

As a part of an ongoing monitoring study of phytoplankton in Yemeni coastal waters, phytoplankton samples were collected from November 2012 to September 2013 at four sampling locations along the coast of Hodeida City, southern Red Sea. A bloom of toxic dinoflagellate Pyrodinium bahamense var. bahamense Plate was observed in August 2013. The population density of P. bahamense were ranged from 1.6 × 104 to 3.3 × 105 cell L-1 (accounting for 41.8 % of the overall phytoplankton community). This finding is the first observation of vegetative cells of this tropical species from the Red Sea. Water temperatures during the bloom was 32°C and salinity was 37 psu, indicating its tropical and subtropical nature. Among the phytoplankton species reported during this study, the red tide-forming species; Trichodesmium erythraeum (14.1%), Protoperidinium quinquecorne (6.3 %) and the known toxic species, Dinophysis caudata (1.4 %), and D. acuminata (1.00 %) were remarkable. It is apparent from our results that the toxic species do occur during many months of the year in the Coastal Waters of Yemen with high abundance observed in August followed by April 2013. Further studies are required to carry out the HAB monitoring for preventing the risk of HAB events that may outbreak in future at the Red Sea coast.