Oil and gas exploration.... There is one Oceans Act MPA in Canada that actually allows oil and gas exploration in the Arctic. I think some forms of bottom-contact fisheries should be automatically prohibited, or at least prohibited according to IUCN guidance.
In 75% of the area of an MPA, the IUCN guidance is very clear that the primary purpose of protected areas is biodiversity conservation, not fisheries management. Biodiversity conservation and the 75% rule means that this portion of the protected area should be free from damaging activities. Underwater mining would be another example. Seismic testing would be another example.