Response assessment of structures deployed at sea is generally to be conducted in the frequency domain. This is especially the case for wave energy devices which are to be designed so that their response is efficient and optimal over the widest span of the encountered sea-states spectral bandwidth. Hence design and optimization of such devices requires a proper description of the actual wave energy spectral distribution within sea-states, especially in areas with wave climates dominated by complex sea-states. Taking advantage of the partitioned wave systems parameters made available in the HOMERE wave hindcast database a mapping of occurrences of complex seastates is conducted over the Bay of Biscay and Channel area showing a prevalence of multimodal sea-states and pointing out a strong regional variability. Additional local studies are conducted so as to provide more insight into the directional distribution of the wave systems and their persistence.