Freeclimb,
You make some good points, and I agree that the oceans aren't homogenous, so using a percentage figure doesn't necessarily convey a clear view.
But it makes sense to preserve the waters around what is now a National Park. My point still holds true - there are very few places in our oceans protected from fishing. If we can't afford it now, when will we ever?
Ever snorkeled or dove around Catalina or other islands offshore of So Cal? I have.. It's a desert, and it doesn't matter who/what you want to blame, sportsmen, commercials, or environmental degradation... Continued pressure on the Channels will eventually result in the same. Banning all fishing short-circuits the fingerpointing and starts the healing.
Besides, there's plenty of other places to fish. But good luck, cause they've already been strip-mined by the same folks who want to do it to the Channel Islands....