Summary. Since 2005, a yearly monitoring of macroalgae according to national WFDregulations (Water Framework Directive) has been performed. Quantitative abundance values were obtained by means of quadrat sampling within a fixed grid of stations in the northern intertidal (in the following text: N-Watt) of the northern coast of Helgoland (Bartsch et al. 2005, MMH-Report 2; Schubert et al. 2007, MMH-Report 5). Concomitantly, species richness was recorded based on the RSL-method (Wells et al. 2007), and diving transects provided sublittoral data on macroalgal abundance and depth limits since 2007. All data serve to fulfil the requirements for the component ‘Macrophytes’ within the biological package of the European WFD with respect to the coastal water body N5 at Helgoland (Kuhlenkamp et al. 2009a, MMH-Report 12). For this purpose, the specifically developed ‘Helgoland Phytobenthic Index’ (HPI) provides comprehensive calculations in a modular format. This leads to the normalised ecological values necessary to establish the final Ecological Quality Ratio (EQR) used for reporting to the EU (Kuhlenkamp & Bartsch 2008, MMH-Report 9; Kuhlenkamp et al. 2009a, b, MMH-Reports 12 and 13). During the present study, sampling of the fixed grid in the N-Watt was undertaken in July 2010 and February 2011 similarly to the years before. In parallel, quadrat measurements along an additional eulittoral transect implemented by LLUR (LANU-SH) were performed in summer 2010 and results were compiled according to previous reports (Schubert 2007, MMH-Report 6; Kuhlenkamp et al. 2009b, MMH-Report 12). If required, metric values were calculated for reporting to the national and international authorities in compliance with WFD regulations. In the following the results obtained are described and their seasonal variation depicted in detailed graphs. Descriptions of the methods have been given in Kuhlenkamp et al. (2009b, MMH-Report 13). During recent months, first efforts have been undertaken to integrate the HPI which was especially developed for the unique Helgoland N5 water type, into the ongoing intercalibration process of the NEA-GIG (North East Atlantic Geographical Intercalibration Group) water types and demands. The state of the art will be reported here.