I suspect Dolphins can tell people apart and will recognize you as not the guy that threw the bottle cap akin to all those stories about crows.
Certainly will be interesting to see how much we can bribe Dolphins to do once we have faster communication methods.
I think you're overestimating the dolphins here. Even humans have trouble not placing collective blame on groups of people they don't know well - it even has a name in social psychology, the "out-group homogeneity effect". Just think about opposing political groups or international relations.
So you think you’re not responsible for the fucked-up oceans because you let other people throw your trash into the sea for you, and the organically farmed salmon you eat surely wasn’t produced under atrocious conditions?
Embrace antinatalism and life denial or embrace amor fati. Sitting on the sidelines like so many others do on this topic is intellectually bankrupt.
Eh, collective punishment is the fallacy.
These problems are generally industrial in nature so it's very knowable as to where a large source of pollution comes from.
There just isn't a political will to actually enforce laws.