The AZAHAB HE516 survey aboard the R/V Heincke (Helgoland) was conducted during summer 2018 to study the coastal oceanographic processes and mechanisms underlying the dynamics of Amphidomatacean species and the biogeographical distribution of their toxins in the water column. The survey transects were from Bremerhaven, Germany across the southern North Sea and the British Channel with detailed sampling initiated in the Celtic Sea and West Irish coastal waters. From Irish waters the transects continued along the Outer Hebrides and the northern Scottish coast to the North Sea, which again was sampled in more detail. In addition to the primary transect, five transects perpendicular to the coast were performed in along the Irish coast. Standard physical oceanographic parameters (temperature: ˚C, salinity: psu, σt ) plus current velocity were supplemented with bio-optical measurements with multiple profiling fluorometers and various passive optical profilers (for turbidity and diffuse attenuation), including hyperspectral radiometers and microscopic plankton analyses, on-board phycotoxin measurements, and real time polymerase chain reaction (PCR).