Not long ago I saw an ice chest with a long funnel built into the lid. It looked like the end of a leaf blower. With the cooler loaded in the rear storage area of your yak the funnel came forward under your armpit. You put the fish in the opening and it slid back and into the cooler. Solved the problem of turning around in your seat and opening the lid. I can't find that anywhere on the web now. Might just build it myself if I can't find it. Will let you all know.
"Give a man a fish, and feed him for a day. Give him entitlements and you may feed him forever."