I have to make another comment here due to TroutHooker's take on "environmentalists". I PROUDLY wear this title like a badge of honor, and I am sure as hell not a "professional fear monger". I happen to make my living as a scientist with a B.S. in botany and an M.S. in entomology (trout fishers, pay attention). There are certainly some uninformed envrinmental types who have not done their homework nor have graduate degrees in biology, but don't put ME or any of my colleagues in this category. In fact, when I hear someone slamming the environmental movement as being scaremongers, it causes ME to assume that the speaker is a card-carrying member of the GOP who gets their information from REAL fearmongers like Rush Limbaugh and Glenn Beck, two of the most uninformed idiots ever to walk Planet Earth. I am going to assume that TroutHooker is not one of their kind, unless he proves me wrong.
Piscicides are tools to be used carefully and with reason, like any other tool. After all, you can hurt yourself pretty bad with a hammer, saw, or even a screwdriver if you are careless. I am personally in favor of their use in the restoration of NATIVE trout populations where they belong, even if that means wiping out foreign browns or rainbows. As far as invertebrates are concerned, my own personal experiences are that invertebrate populations are far more resilient than most people give them credit for. Last summer, a huge silt spill occured on the Pigeon River in northern lower Michigan when a dam opened accidentally due to a faulty sensor set off by an electrical storm. Enormous quantities of mud went sliding down the river, and all of the local trout fisherman declared it "killed". Someone even claimed to have found a dead 22" brown in the stream! Well, an old boss of mine (who is still throwing me crumbs of work in my mostly unemployed state) got the call to investigate the situation, and having a graduate degree in entomology, I got the call to help him out. So we collected a whole bunch of samples in a rigorous, scientific manner (transects with Surber Samplers, timed for 60 seconds, from a variety of substrate types, etc.) from both below and above the dam and its reservoir. Low and behold, we found MANY more insects BELOW the dam than above, and a substantial diversity to boot. We sent the samples out for ID since we didn't have the proper equipment (i.e., a good dissecting microscope), and the results confirmed our anecdotal observations - MORE inverts where the silt spill had occured than above the dam & reservoir. In fact, there appeared to be substantial erosion going on within the stream channel above the dam - sand was actively burying gravel and cobble beds, and it was likely that the dam & reservoir were TRAPPING this sand and preventing further movement downstream. The gravel in the reach just below the dam, where the silt had hit first, was pretty much clean and was LOADED with inverts of numerous kinds, including species intolerant of pollution like riffle beetle larvae (family Elmidae). On top of this, we fished the reservoir just above the dam, and I hooked and (sadly) lost a big fat brown in the 20-22" range on a streamer (one of my KBFs in brown and copper, GREAT sculpin imitation). Given this, our conclusion was that the 22" dead brown found downstream had been blown out of the reservoir ABOVE the dam and probably got its head slammed against a rock or something. And, we concluded this horrible silt spill had NOT had a significant impact on the invertebrate population, even in the short term.
With regards to rotenone, one of the most widely used piscicides, it is a natural product from the Derris plant which has been used to kill fish FOR HUMAN CONSUMPTION for centuries, so I think that if it is bad for humans and other higher vertebrates, we would have found out by now.
I am a scientist because I believe in reason, not emotional hyperbole.
Jonathon
No matter how big the one you just caught is, there's always a bigger one out there somewhere...