I also agree you shouldn’t fish for pike in canals in the summer
I fish canals for pike in the Summer, never had a problem in 25 years of doing so. I fish at night a lot too when oxygen can be at its lowest, still yet to have a casualty.
I don't conform to the idea that they die later out of sight after swimming away either, as i've had lots of repeat captures.
Also to date i've never come across any dead pike that i've previously caught, i often walk past stretches of canal i've fished the day or days before when heading to fish another stretch.
Truth be known, i've seen no evidence whatsoever to support problems when fishing lures for pike in the Summer.
My opinion is that if problems do occur, it's down to handling and the playing of the fish.
99% of pike casualties that i come across are found in the Winter, that's when a good few inexperienced lads turn to pike & problems occur.
My advice to the lad who started this thread would be to fish heavy, get the pike in pretty quick if possible. Have someone with you to show you how to chin, unhook & handle pike.
Phil.