Do you think a vegetarian could do this diet?

I do eat SOME wild fish when I can find it. (Because farmed fish should not be consumed more than once a month.) I dont want to eat fish every day.
So fish is a a one or two time a week thing.

Yes you sure can. Soy products are fine on this plan, as well as fish. Dairy plays a minor role so cheese or dairy wouldn't be a primary protein source.

I too am trying to stay away from the farmed fish, but the wild sure can be $$ around here at least.

I find it harder. My H and I used beans as a primary protein source, and Gutterson tells you not to have more than 1/2 c. of beans a day. I usually have to end up modifying any diet plan in order to fit it into our vegetarian lifestyle. It's also frustrating when most of the recipes call for meat or poultry; it's slim pickings for the vegetarian recipes.

In the book, yes it is slim; but I have hundreds of recipes for the Med. diet that I modify for the sonoma.