Feed them bones and all to pigs. Turn them into bacon!
We already do that
Fish meal
The Spanish speaking hog farmers call it arena de pescado
When I owned cargo ships I had a contract to carry fish meal bulk from Peru to San Jose Guatemala and bagged sugar back to Peru
Its major hog food and used in other feeds primarily to feed farm raised fellow fin fish
Here in Nashville I see fancy named carp in restaurants....its cod like
Fleshy...not bad
But it aint flounder or pompano or hog snapper