Prorocentrum lima is one of the microalgae species in Dinoflagellates group, which could cause Ciguatera Fish Poisoning (CFP) syndrome. P. lima commonly found it attached to various kind of macroalgae species and could cause human poisoning through biomagnification process in the food chain. Research on the abundance of P. lima and the environmental factors influences had been conducted in Karimunjawa Island, on 24 August 2018, and the objective of the research is to analyze the P. lima distributions in Karimunjawa waters, based on the cells abundance and environmental factors. The research was carried out by collecting macroalgae Padina and Sargassum at four stations, in the reef flat of Karimunjawa Island. Macroalgae were put inside plastic bottles and vigorously shaken by vortex (12500 rpm, 1 minute). Water samples separated from the macroalgae, filtered through a series of sieves, and then …