S-3 EUROHAB will tackle the common marine environment challenges of harmful algal blooms (HABs) and poor water quality (WQ). HABs are naturally occurring phenomena caused by excessively high growth of microscopic marine algae which release toxins into the marine that can kill fish, shellfish and humans. Eutrophication is the anthropogenic enrichment of water by nutrients causing accelerated growth of algae and a deterioration in WQ. HABs require specific light, nutrient and temperature conditions for them to bloom and produce toxins. The frequency and magnitude of HABs and poor WQ are increasing globally, posing high risk to human health and shellfish industries. HABs cannot be eliminated or prevented but only monitored and predicted.A cross-border approach is required because HABs often start in one area and evolve to become problematic in another. This project will improve the ways in which HABs and WQ are currently monitored in the FCE by enhancing spatial and temporal data coverage to facilitate faster response times and better spatial management of these events, to make operations more cost effective. HABs and toxins are currently monitored using boat surveys for collection and analyses of discrete water samples. Detection of HAB toxins over threshold levels results in closure of an entire shellfishery which is regulated by UK&Fr government agencies. This procedure is necessary to safe guard human health, but could be improved using satellite data to make the current monitoring effort more efficient. To achieve this, S-3 EUROHAB will develop 3 main outputs: A cross-border data portal that will be used to assess the environmental drivers, transport and dispersion of key HAB species in the FCE, an assessment of GES baseline in the Channel for the MSFD and for the development of satellite algorithms to detect these events; A web based HAB and WQ alert system designed with marine managers and industry end users; A socio-economic survey of the cost of poor WQ and HABs and the benefit of using the web based alert system. These outputs will be developed in collaboration with the project target groups who are Marine Managers, Marine Policy makers and Scientists. Fr &UK have established complementary monitoring programs and developed different satellite algorithms that could be jointly applied to tackle these common problems. During 2015-16, Copernicus (the European system for monitoring the earth) launched a series of satellite sensors (the Sentinels) to enhance the marine monitoring for the next 20y. S-3 EUROHAB will use this latest satellite technology to develop and test HAB and WQ detection algorithms for the shellfisheries to address CP Challenges 5 & 6. The value of the SW UK shellfishery is €8.25M per yr, of which €2.9M is lost to HABs which could be saved by an alert system. The current costs of monitoring HABs in the FCE is €2M per yr which cover 6% of the FCE. With the S-3 alert system the cost is €42K per yr for the entire FCE.