We’ve been making fish soup from the remains of our salmon for years and just love it. After cleaning the salmon that we dip net from the Copper River at Chitina, we cut off the tails and heads from the gutted and fileted carcass, saving the carcasses and the bellies and some of the heads (about 1 head to 3 carcasses).

Ingredients (balance according to amount of stock)

fish carcasses and heads
bay leaves
thyme
wild rice
barley
carrots
celery
onion
garlic
white wine
V8
parmesan cheese heels (optional)
salt & pepper to taste
chopped scallions
grated parmesan cheese

Simmer about 18 salmon carcasses and six heads in a canning kettle (or other very large vessel). Pack them in and just use enough water to cover them. That way you don’t have to spend much time or energy concentrating the broth.
When the meat is loose, cool.
Pick meat into a separate bowl as you discard the heads, bones, and carcasses.
Strain the remainder to get out bone chunks and other debris.

Fish soup stock simmering.

Return stock to a smaller pot and bring to a simmer again, adding bay leaves, thyme, wild rice, and barley.
About half an hour later, add:
carrots, celery, onions, garlic, white wine, V8, parmesan cheese heels, and salt and pepper to taste.
Cook another 10-15 minutes, check on rice/barley for doneness and check the flavor; juggle ingredients.
When it seems done, add back the picked meat.
Fill soup bowls and add chopped scallions & grated parmesan to the top.