[notahacker]

If I was an sonar-equipped aquatic mammal that was also superintelligent, I'd expect generations of losses might have taught my civilization not to swim near boats.

(Unless we're positing that running the risk of being trawled is an essential part of mucking about and having fun, or a scientific experiment, or dolphins having enough imagination for some of them to speculate warnings about boats are a conspiracy to keep them from the best fish :D)

[pilsetnieks]

Boats go where your food is. Avoid boats and you'll have to avoid the most plentiful food sources. Either starve or run the risk that you might stumble upon a boat and someone from your group might get tangled.