The occurrence and composition of toxic algae, and presence of viruses and other human microbial pathogens in production areas of mussels are factors determining suitability of mussel products for human consumption. As bivalves feed by filtering large volumes of water, potentially toxic viruses, algae, and bacteria as well as phytoplankton are ingested. With the expansion of mussel aquaculture and subsequent increase in human consumption of mussel products, improved risk management is required for consumer protection. For example, shifting production to offshore areas (e. g. wind farms) can decrease the hazards of infection due to dilution of contaminants, and increase overall health of mussels. In addition, the deployment of off-bottom cultivation methods such as longlines increases the condition index, growth, and aesthetic appearance of mussels. However, other hazards like algal toxins not yet monitored on a regular basis, may play a more important rule offshore. Here, we present an analysis of biological, economic, and consumer health-related aspects of mussel cultivation under near- and offshore conditions. © Springer-Verlag 2009.