I've heard and read the same thing.That fish hung verticle have a greater chance of mortality,that they should be supported under the belly and the gills,and are not created to be hung by their jaws.Now easy boys,only relaying what I read and heard.
That makes sense poleski. All their life fish are effected by gravity in a horizontal position. Probably not made to withstand the vertical force of gravity out of the bouyancy of water.
Cal
From what I have read and been told .You should NOT weigh any fish you plan on releasing.
Just my .02
I have Cabelas spring scale that works well.
I could have sworn I made a post on this to I'm In, oh well, maybe I did elsewhere ??? I did some research and you are 100% correct, "fish to be released should not be weighed by coventional methods we use". I'll see if I can pick out some highlights from F and G biologist and post it here, he had allot to say on the subject. The drops they put in the water are a controled substance, forget that idea, people would be smoking it, lol.