During spring and summer 2004, intensive field campaigns were conducted in the Eastern English Channel. This region is characterized by relatively intense phytoplankton blooms, low bathymetry, strong tide ranges and great river inputs. The sampling period accounts for episodic blooms of prymnesiophyceae <i>Phaeocystis globosa</i> and diatoms. Hyperspectral radiometric measurements (TRIOS; 350-950 nm, with a 3 nm spectral resolution) were concurrently performed with water sampling for biogeochemical and optical characterization. The remote sensing reflectance, <i>R<sub>rs</sub></i>, is analyzed in conjunction with variation of the water composition. We particularly focus on the capability to identify some phytoplankton species from <i>R<sub>rs</sub></i> in this very variable environment. Different methods, based on multispectral and hyperspectral data are tested and compared for that purpose. We show that no <i>R<sub>rs</sub></i> ratio allows to discriminate between diatoms and <i>Phaeocystis</i>. In contrast, the derivative analysis applied to hyperspectral data stresses large differences in some part of the <i>R<sub>rs</sub></i> spectra collected in diatoms or <i>Phaeocystis</i> dominated waters.