Harmful algal blooms and their effects in coastal seas of Northern Europe

•Fish mortalities due to harmful algae cause substantial economic and social costs for the fish farming industry in the northeastern Atlantic, North Sea and adjacent European waters•Toxin syndromes associated with Diarrhetic Shellfish Toxins and Paralytic Shellfish Toxins and their regulation have the most profound effect on the bivalve aquaculture industry in the northeastern Atlantic region•Cyanobacteria and cyanotoxins are mainly problems in brackish water areas, particularly in the Baltic Sea•Emerging threats to the shellfish and finfish industries include the known presence of the phycotoxins azaspiracids and goniodomins•The IOC-ICES-PICESHAEDAT contains time-series baseline information on harmful algal events in Europe