Raphidophyceans on the coasts of Mexico

The presence of ichthyotoxic phytoflagellates Chattonella marina, Fibrocapsa japonica, and Heterosigma akashiwo of the algal class Raphidophyceae are reported for first time in the Gulf of Mexico and the Pacific coast of Mexico. Phytoplankton were sampled to isolate and identify species, and to develop growth experiments in different media. We observed living material of the three species, but were unable to recognize specimens in preserved samples. Cultures were established by isolating single cells and diluting phytoplankton samples in modified f/2 and Erd-Schreiber media. Features, including morphological variations and pigment composition, of living cells under various nutrient conditions are described. These ichthyotoxic species produce harmful blooms in several parts of the world, although no documented cases have been reported in Mexico.