Who has cut up a mahi mahi before?

What is inside that lump above its head?  Meat?  Bones?

http://www.jerrylabella.com/pictures/mahi_mahi.gif

Distinctive Features
The two species of dolphinfish are easily distinguishable. Both exhibit the same elongate, fusiform body shape. The single dorsal fin extends the length of the body. The anal fin begins approximately in the middle of the body and ends at the same point as the dorsal fin. The pelvic fins are located under the pectoral fins and can be compressed into a shallow groove on the body. The caudal fin is strongly forked. The head is blunt and the mouth contains many small teeth as well as a small and oval-shaped tooth patch on the tongue. Cycloid scales cover the body. Displaying sexual dimorphic growth, mature males develop a prominent bony ridge at the front of the head. The dolphinfish can be distinguished from the pompano dolphin (Coryphaena equiselis) by its body depth. Body depth of the dolphinfish is less than 25% of its standard length, while the pompano dolphin body depth is greater than 25%. The anal fin is concave and pectoral fins half the length of the head.

They're pretty easy to fillet, once you go back far enough. I've found that when I start just behind the dorsals -as you would with most fish, you're still into some sort of very bony/rigid tissue.   If you move a little bit further back where the knife easily cuts into the meat, it all goes smoothly from there.   No more bones than any other fish as far as I know, but I have never found a way to get meat from the head - it seems pretty solid to me.
Ron

Ahem - whoops... that should be "start behind the pectorals..."
Ron

Bone, but not a solid crown.
http://www.helterskeletons.com/dolphinfish.htm

And just for kicks, one of my favorites in filleting: