Biosecurity risks associated with in-water and shore-based marine vessel hull cleaning operations

► We compare the effects of in-water and shore-based hull cleaning on biofouling. ► Biosecurity risk may be associated with surviving non-indigenous biofouling. ► In-water cleaning is associated with greater rates of surviving biofouling. ► Shore-based hull cleaning effluent treatment systems reduce biosecurity risk. ► Effective biosecure tools for in-water hull cleaning are required.