Perhaps its time to follow the Yellowstone National Park example with NNIS.
http://www.nps.gov/yell/planyourvisit/upload/14FishReg.pdfEXAMPLE SECTION (what they do in yellowstone, note Rainbows are non-native to that area)
Northwest Region
Possession Limits
Native Trout Conservation Area:
• Catch and release all native fish.
• No possession limit on nonnative
fish.
Nonnative Trout Tolerance Area:
• Limit of 5 brook trout.
• Catch and release all rainbow and
brown trout.
Northeast region
All non-native fish must be killed in the Lamar drainage.
And another one
All Lake trout must be killed in Yellowstone Lake.
Or another one.
Illegal actions which cause
ecosystem degradation
• Possessing a native cutthroat
trout, or any other native
fish.
• Releasing a nonnative fish
alive within a mandatory kill
area.