You find a stick of dynamite floating in the Briny Deeps. Looks like some "fisherman" forgot to light it before he tossed it overboard.
You pull out some waterproof matches (you always carry waterproof matches in case of a situation just like this one,) light the fuse, close your eyes and stick your fingers in your ears. After a few moments, there is a massive splorch sound, and you find yourself surrounded by fish meat.
You're not sure what happened. Maybe there was a container ship passing overhead laden with crates of fish, and the shockwave knocked one loose? Yeah, that was probably it.
Occurs at The Briny Deeps, semi-rarely.
Adventure refers to blast fishing.