Background and Objectives: Noctiluca scintillans is a dinoflagellate without armor that has extensive winter blooms in the northern Indian Ocean. Green layers from dense algal masses of N. scintillans were observed in all the studied stations in the winter, PGE 1801 cruise of the Institute of Oceanography and Atmospheric Sciences in the Strait of Hormuz. The aim of this study was to an assessment of the distribution of the bloom in the winter of 2017 in the Strait of Hormuz using field data and remote sensing.

Methods: The density of N. scintillans species in the upper layer of water was calculated using closing net samples. The density of other phytoplankton was obtained by direct sampling of water by Niskin sampler. In all stations, the profiles of salinity, water temperature, and chlorophyll A parameters were measured from surface to layer close to the substrate using CTD. MODIS satellite data were used to investigate the distribution and extent of the bloom.
Findings: The results of correlation analysis (Pearson) showed a significant relationship between chlorophyll A (values ​​obtained from remote sensing) and the number of N. scintillans cells per liter (R = 0.74, P <0.05).
Conclusion: It seems that the intensity of N. scintillans bloom is higher in the western part of the Strait of Hormuz and the waters near the coast. Also, satellite remote sensing data show that there is a strong correlation between the distribution of N. scintillans bloom and mid-scale eddies in the Strait of Hormuz.