Page 23 of the regs prohibits "intentionally wasting" game fish. Not sure whether the legislative history of this provision, or a field enforcement officer, will interpret placing the carcass back into the water as being an "intentional waste".

It's interesting to note that page 23 of the regs uses language that requires use of salmon, herring, and halibut for human consumption or fishing bait, rather than using the "intentional waste" language.