Kelly-- I probably should quit telling my old war stories about the cyanide (we did this back in the mid 70s). However, it was great for sampling, especially for stream sampling. It came in small white briquets, about the size of a characoal briquet. One briquet per cfs (cubic foot/second) of stream volume, and fish would float up through the next couple of pools. We'd put a block net at the start, and near the bottom, and then set up tanks of fresh water at regular intervals. The cyanide was reverible, if the fish didn't get too much, and you quickly got them in fresh water. If we hurried, and netted fish quickly, they could be revived. Meanwhile, the cyanide was just a gas dissolved in the water, so by about the seccond riffle, it would escape into the atmosphere, and no more fish effects.
I can also remember using it in a gravel pit in Colorado. We put the briquets in a burlap bag, and towed the bags behind boats. As the largemouth bass started to pipe on the surface, we'd net them, and put them in fresh water tanks to revive them.
I'm telling stories like a old-time fish squeezer, aren't I?? It's hard to believe that we used something so dangerous, with so little concern. We sure didn't carry an antidote, even though we were wading through streams with the cyanide gas coming off around us.
Anyway, that's the explanation.
Dave
