inb4 chicken + beef creates an anabolic effect:
Hey Scubar
I've used pea protein for the last year and I'm currently on my second bulk. I don't find that it has hindered my progress whatsoever. Given its comparatively high level of BCAAs, high digestibility and very low price, I think it is easily on par with whey.
Otherwise, the only difference between your diet and everyone else's is that you are missing out on red meat and chicken. Now that you're eating plenty of fish - I don't really see a problem. There are some tables out there about the bioavailability of the protein in certain foods. However, you'll see that whey and eggs sit at the top, not meat and chicken.
I think generally the problem that a vegan/vegetarian bodybuilder would struggle with is hitting their protein macros (and maybe their calories overall for gaining). Supplementing with pea protein, maybe adding in natural peanut butter and trying to have lentils with your food as often as possible (given their decent protein levels), would probably help.
Although I have to admit, I haven't met many 'big' vegetarians.
Cheers