Due to strong tidal currents and harsh hydrographic conditions the German Bight is used only in the sheltered nearshore areas for on-bottom cultivation of blue mussels, where space, however, is limited by other stakeholder, e.g. shipping traffic, tourism and environmental protection. An expansion of this food production sector within intertidal and subtidal areas of the coastal sea is not allowed due to legal restrictions. The possibility and profitability of additional offshore longline cultivation within the planned offshore windfarms is assessed by a project coordinated by the Alfred-Wegener-Institute for Polar and Marine Research in Bremerhaven, Germany. In 2006 and 2007 blue mussels were cultivated in the area of the planned offshore windfarm Nordergründe. Samples were analysed by using biodiagnostic tools and by assessing growth rates and microbial, toxicological and parasitological parameters to determine overall health and consumption suitability of the mussels. In addition, the current regulatory framework of the official monitoring of mussel products was critically evaluated. First results show that an adjustment of the existing regulations and a differentiated approach according to the site specifics and cultivation method seems to be timely to improve consumer safety. © Birkhá user Verlag, Basel/Switzerland 2009.