 Although the county of Humberside no longer exists, Natural England curiously uses its former borders to mark an Area of Search., there are 72 sites designated in this Area of Search, of which 51 have been designated due to their biological interest, 17 due to their geological interest, and 4 for both.Natural England took over the role of designating and managing SSSIs from English Nature in October 2006 when it was formed from the amalgamation of English Nature, parts of the Countryside Agency and the Rural Development Service.