That, and if you are brutal enough with the net, you can damage every fish in it enough to bleed.
That’s true and if you bring them up from a depth as well. Trusting those fishermen know the difference though. Sounds like something they’ve not seen to this extent. Could be biological or something secondary as result of the radiation. Some organisms proliferated in high radiation environments. Do a search for what they’ve found growing inside the Chernobyl esophagus. Then there’s the legend of Godzilla... ;)