I try to for the salmon & steelhead. Doesn't always happen. Initially I wanted to know how much of the fish doesn't make it to a plate (about half) and now it's just for bragging rights & trying to spot trends (there aren't any, LOL). So this salmon was about 13 lbs and I ended up with about 6.5 lbs of meat... that's like 7-8 large cans worth, since we made salmon patties instead of baking filets or steaks.
It is amazing how a few simple ingredients & spices turn a poor quality fish into a luxury meal. We cooked the first batch of salmon patties using about a third of the fish and they're a treat! That was a dozen patties and I've eaten three before calling it quits for tonight.