I can only give my opinion on fish preping after capture. I have always dispatched fish as quickly as possible. Bleeding a fish makes a world of difference regardless of whether its to be eaten that night or frozen for the future. An ice slurry (saltwater and ice) is without doubt the best way to prep them for eating it drops the temp real quick and stops the inevitable breakdown of cells for a little while.Try yourself you will see how much blood the body maintains if you dont bleed a fish . If you want to keep fish for any period I suggest filleting skin and scales on flesh to flesh and vac seal. for a 200 dollar peace of gear believe me you can preserve fish for a long time and in top condition if you go the extra effort.You will find any fish will be in top cond following these tips.
I shared a house with a chef years ago and he bbqd a fish on the beach one day he filled the blue bone with lemon slices ,butter salt and pepper cut the scaled skin and did the same butter ,lemon,salt pepper wrapped in foil and cooked it slow on coals. About halfway through he opened the foil and tipped half a cup of fresh sea water (depending on the size of the fish) and let it steam for a while open to the coals and smoke .It was an amazing meal