An assessment of Dinophysis blooms in the coastal Arabian Sea

•Generalized Linear Model suggests that sea surface temperature (SST), salinity, N:P ratio and total suspended solids (TSS) are important factors in driving the toxic Dinophysis species in the Arabian Sea.•Frequency of Dinophysis blooms can increase in the future, given the climate change scenario in this region.•The current findings add substantially to our understanding of prediction of harmful algal blooms using statistical models. Dinoflagellate blooms of the genus Dinophysis occur regularly in the coastal Arabian Sea. By producing toxins, which may accumulate in marine bivalves, they impose threat to human health. Using time-series data on environmental variables (e.g., nutrients, sea surface temperature and salinity) and concurrent Dinophysis abundances for the surface waters along the coast of the southeastern Arabian Sea during the period 1990–2010, we investigate whether potential climate change signals play a role in driving blooms of Dinophysis spp. A logistic Generalized Linear Model was adopted to test the effect of environmental variables on Dinophysis abundances over a range of threshold values (102–105cellsm−3) for blooms. Some of the extreme events occurred during the pre-monsoon (March–May) periods. Model validation suggested a threshold of 105cellsm−3 to be better than other thresholds in examining the Dinophysis abundances, and the variation in this threshold is explained by sea surface temperature, salinity, dissolved inorganic nitrogen to phosphorus ratio and total suspended solids (turbidity). Fate of the Dinophysis blooms in the coastal Arabian Sea for different climate change scenarios is discussed.