Fascinating the observations that come from an eclectic group of fly fishers. Never gave it much thought about fish eye and/or dorsal fin position while releasing or holding fish.
At first, I thought, let me hear other responses in this matter before I voice mine. As usual your summations are always true and correct. Like all animal behavior, the same correlation cannot be true each time. Aspects like the behavior of the fish, how it was fought, length of fight, time of year, condition of the fish and how it was held all contributed to the fish's factor how it might behave.
Knowing this much, and having some holiday time, I searched the scientific community for some knowledgeable answers. Talked to experience fisherman, fish biologist, conservation officers, American Littoral Society and a bunch more. Spent hours compiling their opinions and information.
Lastly I did some field testing of my own in the Seekonk River that proved more beneficial.
During a three hour tide I caught and released four schoolies in the 16 - 22 in range. Fought them at various interval and duration's. Held them in various positions both vertical and horizontal. Held them in my hands in different ways. My findings was astonishing and I mean no disrespect to anyone who holds a fish.
I know these test were not conducted under any scientific guidelines. Yes, I could have called GregO at MIT, but I didn't. He was already involved in the question and I felt it would taint the results. Yes, I could have been in touch with Juro, after all, who has fished in more elements than he has. Yes, I could have called Sully, the founder of the question, but I didn't. And Roop and Matt for their impute before I made my hypothesis. But once again I didn't. I didn't want to shock their world.
My fact finding mission proved without a doubt, - ALL THESE FISH WERE FONDLED BEFORE RELEASE IN EACH PHOTO. Yes , the results are quite shocking. We do have some sick fisher's out there.
For now on, all my fish will be release in a dignified manner. Your rebuttle, if you have one is appreciated.