It depends on the objective of the marine protected area in question. As Dr. Pauly mentioned, countries will put aside areas for strict protection, for the continued survival of biodiversity, where there are only activities like tourist visits. Sometimes tourist visits are compatible.
You have situations where there is perhaps some compatibility, but then in multiple-use marine protected areas, we accept sustainable activities that can have some impact. There is a continuum in that process. It doesn't mean that if you are stopping fisheries you should stop other things. It depends on your objective for the marine protected area.