At fish camp we cut off the collars, pelvic fins, and that portion of the back that you miss between fillets (basically the top of the fish excluding the backbone). Back at camp, I marinade them in butter and spices and cook them over an alder fire. It is excellent! And the best part is all the fillets go home and none of the fish is wasted.

Collars
Wings
Dorsal strip

Have a boatful catch their limit and you can feast off these three things w/o getting into your fillets.