Modelling the distribution of rare and data-poor diadromous fish at sea for protected area management

•Rare diadromous fish distribution modelled across eastern Atlantic waters.•Bycatch by different fishing gears was quantified using Bayesian models.•Most species had a shallow coastal distribution connecting with watershed presence.•Existing protected areas could protect species if specific measures implemented.•Limiting access of certain gears in protected areas may help protect these species.