About 15 years ago when I was working with NCSU's Zoology dept., we, along with NC Fish and Wildlife, did some stream sampling above and below some of the commercial trout farms in western NC to try and get a handle on the impact of farms on the swimmers and crawlers that called the streams home (turns out that the trout farms seemed beneficial in pretty much all cases).
We were using a modern version of your phone shocker, Sam; a small backpack mounted generator powered by a little 2-cycle engine. There were two 5' aluminum wands connected by cables that the "electrocuter" carried in rubber-gloved hands and waved in the water in front of him as he walked up the stream; one wand had a little net fixed to it so that he could collect the stunned creatures and put them in buckets for weighing, counting and classifying (and releasing, of course). Though I got to handle the shocker a little bit, what I did mostly was to follow right behind with buckets and regular nets collecting what floated past the shockers. Luckily the apparatus had a very limited "sphere of influence", so the danger of getting shocked to those of us who were following them was minimal, but it still made for some funny moments as we made our way upstream in rubber chest waders trying to keep from ending up in Davy Jones Locker- LOL. Dang, those rocks get slippery!
In addition to wild and stocked trout, we came up with crawdads, black-nosed dace, and one particularly evil-looking, but very docile hellbender (see
http://en.wikipedia.org/wiki/Hellbender ).
Disclaimer: No animals were permanently harmed as a result of their shocking experience (we might have hurt their feelings, though ;~)
Bryan
