Objectives The objective of the study is to assess how phytoplankton composition and quantity enhanced by forced upwelling of nutrient rich deep water in a fjord affects growth performance and detoxification in cultured mussels. Sub goals are: 1. monitor the fjord environment and succession of phytoplankton including toxic algae, 2. contrast feeding and growth performance in mussels affected and unaffected by the enhanced phytoplankton assemblage forced by upwelling of nutrient rich deep water, 3. estimate elimination rate of algae toxins in mussels introduced to enhanced phytoplankton concentration forced by upwelling of nutrient rich deep water.