International audienceThe identification of phytoplankton is currently an important issue to prevent the aquatic environment. The growth of one or several phytoplankton species can lead to hyper eutrophication and causes lethal consequences on other organisms. In this paper, the selective recognition of invading species is investigated by automatic recognition algorithms of optical and fluorescence imaging. Firstly, morphological characteristics of algae of microscopic imaging are treated. The image processing lead to the identification the genus of aquatic organisms and compared to a morphologic data base. Secondly, fluorescence images allow an automatic recognition based on multispectral data that identify locally the ratio of different p...