About five years ago, my wife and I were in Hawaii. While we were on Kauai, we took a half day Bass/Peacock Bass fishing charter on an inland reservoir.

The guide described the body of water to us. As the water was fairly clear, you could see that there was no vegetation whatsoever. The guide said that this was because tilapia were introduced and because there was not enough predators to eat them, they basically took over.

Every once in a while, you would see a school of tilapia in the 3-5 lb. range zipping past.

I would suppose that there was no winter kill-off for the tilapia there.

We only caught one LMB and a few peacock bass with none over 5 lbs.

I have no clue as to whether the tilapia were "good" or "bad" for that body of water.

There was a good amount of rubbish dumped around the shores of the reservoir (supposedly by the locals). I was not too impressed with the whole thing.

Excerpt from Robert Crais' "The Monkey's Raincoat:"
"She took another microscopic bite of her sandwich, then pushed it away. Maybe she absorbed nutrients from her surroundings."