Can anyone on here tell me just how fragile a trout is? I thought I read in a post of a plac where hatchery trout were dumped off of a 50ft bridge into the river? If that's the case, a little squeeze shouldn't hurt them too awful much. I'm not condoning superfluous squeezing, but what is the truth of the matter?
The times I've witnessed stocking, it was done at a short distance if dumped. The truck usually has some type of chute or large diameter hose. Otherwise the fish are carefully placed in containers & carried to places along the stream, & released by hand. But as you say, it probably happens in less than favorable manners too sometimes. I really don't know how much damage such releases may cause.
I'm sure we've all heard the new's reports of human babies falling off 2nd or 3rd floor balconies without any harm. Most animals can take a certain amount of rough treatment, and sometimes even in extreme cases, like the babies, it's surprising there is no or little damage, but that's not the point.
I've seen folks squeeze many species of fish until the vent was pushed way out & even bleeding from the vent. When that type of damage occurs, you can bet the fish stand little chance of surviving if released. But, some may anyway. If they're putting them on a stringer to take home & eat, it really doesn't matter much.
The point is to use your head about how you handle any species you do not wish to harm & wish to release to be caught another day. There is going to be some harm, even if it's just the small hole from the hook, it's fishing, but we can do things that minimize it, by how we choose to handle a fish.