Proliferation of Pseudo-nitzschia brasiliana and P. cf. pseudodelicatissima (Bacillariophyceae) in the Estero Santa Cruz, northern Gulf of California, Mexico

A moderate bloom of Pseudo-nitzschia species occurred during collection of phytoplankton in Estero Santa Cruz, the State of Sonora, Mexico, in August 2012. The abundance of Pseudo-nitzschia in 2 samples was 84x10(3) and 160x10(6) cells L-1. Results show the presence of 2 species, P. brasiliana and P. cf. pseudodelicatissima, which were responsible for a microalgae bloom. This is the first proliferation of P. brasiliana in the Gulf of California. P. cf. pseudodelicatissima was present in higher densities. A short morphological description is provided, including data from scanning electronic microscopy.