This is the "proper" way:
But I don't do half of that... I just do two slices behind the pectoral fin (two on each side).
I then cut a small slice in front of the tail about 1/2 an inch in from the end if the fish(why? I don't know since it does seem to do much....)
I keep the saltwater washdown on the fish to prevent clotting.
After it is dead, I cut around the anal opening and push that back in the fish.
I then cut about a 3 inch hole in the belly, reach in and cut away all the guts, etc.
Lastly I remove the gills and pack it with ice...
There are a million variation on the theme though...