[Riddick's eyes snap open, and the danger to his lure outweighs his hunger for the moment-- so he punches the other merman in the chest first, and then tries to get a net over him. And as soon as it's free, he whips the cartiliginous appendage protectively behind his back, sheltering it amidst his fins.]

Don't eat my fucking lure, are you stupid-?

[Given his hereditary and very functional underbite, this comes out more along the lines of 'don' ea' my vfucking lure, ah 'ou ftupid?' But it's probably not wize to mention.]