Just finished "Game Wars" - "The Undercover pursuit of wildlife poachers." By Marc Reisner. Published in 1991, might be a tad hard to find, but it's probably on Amazon. The book covers some of the cases of wildlife poaching taking place in the 80's. Ivory from walrus in Alaska, Louisiana ducks, crappie and deer. The descriptions of some of the poachers are hilarious, but some of those dudes were bad characters. What surprised me was how big the crappie poaching operations were at the time.