According to Science Daily, the small-island state of Kiribati just established the world's largest marine protected area (MPA). The Phoenix Islands Protected Area (PIPA) is the size of California, though the article does not provide a map nor does it mention what portion of the MPA will actually be closed to fishing (most MPAs allow some sort of activity inside). The article does mention that commercial fishing will be 'restricted'. Currently, around 0.6% of the seas were dedicated as MPAs (as compared to the 12% terrestrially). Furthermore, only 0.01% of the oceans are closed to fishing.
Another study in Science today (to be discussed at AAAS this weekend) constructs the first global map of human influences on marine ecosystems and suggests that ~41% of the oceans have been heavily impacted by humans (via fishing, nutrient runoff, and 15 other variables) and that few blue spots on our planet are likely pristine. At Science, it's been termed the map of misery:
[Red and orange areas (e.g., the Eastern Caribbean, the North Sea, and waters off of Japan) indicate highly impacted areas.]
The marine protected area PIPA, supported by the New England Aquarium, Conservation International, and, of course, Kiribati, is certainly a great step in the right direction but can't be the last...