Causes of Harmful Algal Bloom Outbreak of Cochlodinium sp. in Persian Gulf; Problems, Threats and Control

The aim of this work was to identify the agents of algal bloom (red tide) and its distribution pattern in Bushehr Province’s coastal zone, the causes and mitigation methods. Field investigations and samplings were carried out during December 2008 to November 2009 from Nayband bay in the south of Bushehr Province to Deylam port in the north. The first outbreak of the bloom was reported on 25th November 2008 in Nayband bay south of Bushehr Province which finally reached the southern part of Genaveh on 27th January 2009. Based on the phytoplankton identification, the algal bloom was caused by Cochlodinium polykrikoides belonging to Dinophyceae class of Gymnodiniales order. The highest density of Cochlodinium.sp was 8,700,000 cells/lit in December 2008 which declined in winter 2009. The density of this phytoplankton increased to the maximum of 4,120,000 cells/lit in April 2009. The correlation coefficient between density of Cochlodinium.sp withconcentration of phosphate and nitrate in Nayband bay station were +0.99 and +0.98, respectively.