the '22' was caught on a flying'C' while salmon-spinning late March.
Unlike Philip (above) I won't criticise the non use of an unhooking mat.
However, late March you say, Cliff - clearly this was a female and doesn't look like she's yet spawned. Whether she had or not, this could be a fish in a critical condition and maybe that was reason she succumbed. It may not have had anything to do with you hooking her even, just nature was maybe too much for her. It happens.
If this is true then it had nothing to do with trebles either. Maybe we will never know and if it is true, it might say something about the close season for pike since many will be in a critical condition from January onwards, perhaps?
The difference between a barbed hook and a barbless one is that when a barbed hook is pulled into the flesh it stays fixed and the tip of it doesn't rotate about the same as a non barbed hook. The non barbed hook penetrates a lot deeper also and because of the lack of even a very small barb it moves about at the tip and creates a crater under the flesh. After a while the fishes mouths can appear sunken inwards because of this. You might say how do I know this, but it's quite obvious when you visit a barbless only water.
Also after being hooked on a number of occasions myself I've felt the difference.
I don't think anglers will ever agree on this matter and the only way to prove it one way or the other would be to have some lab rat type fish and keep catching them to see the results.
I would contest a lot of what you've said there, Tigger, but you are welcome to an opinion. My reason for disagreeing is that 20 year ago almost, a friend (he was a shareholder in a lake rented to a club) asked me why a lot of the carp had deformed mouths, ripped top lips etc. and the club who rented the lake believed it was the use of boilies. They had a rule of no hair rigs or boilies and barbless only, but with a few exercises I felt that I proved it was neither boilies on hair-rigs nor barbless hooks (in the close season, only the shareholders and their guests could fish and rules didn't apply).
I had an inkling and later felt even more sure that the tears in the mouth were from the hooks being deep in the mouth and the line coming out of the 'scissors', as we call them. With force from the pole or rod, the line cut through the lip quite easily (I stress, I didn't try this). The cause I felt and later witnessed was the match anglers using very strong elastics and virtually hauling the fish in rather than playing them. This was to accumulate a bigger match weight and this also was the cause of the twisted mouths with, probably as you say, the hook twisting around in the hook hold, but that could well have happened whether it was a barbed or barbless hook.
My evidence is like yours, purely anecdotal and proves nothing either way. It did help when the match anglers were advised to use weaker elastics and play the fish a little more. After a while, mouth damage did seem to reduce, but it's still hard to prove one way or t'other.
mg: