State wildlife biologists are teaching a survival training course for native fish. In a watery lab near Cornville, Matt O'Neill with the Arizona Game and Fish Department, injects predatory game fish with a Botox-like substance to temporarily paralyze their jaw muscles. That gives him time to teach hatchery-bread native fish - like Razorback Suckers and Bonytail Chub - to steer clear.
O'Neill says, "They absolutely don't recognize these big Catfish and Bass as something they should be afraid of, and so, of course, when you put these native fish into the wild, they suffer from all kinds of predation threats. They likely won't survive their first encounter with one of those predators."
He explains Arizona's native fish didn't evolve with game fish. They were introduced into the Colorado River system and have eaten native fish into near-extinction. O'Neill says the small fish often swim toward danger, hoping to glean a little shade from their predators or swim with them. When O'Neill freezes the jaws of the larger fish, he also adds the native fishes own stress hormones to the water. That alerts them to the danger, conditioning them to stay away.
He says, "The training improves survival at least 30% for both Bonytail and Razorbacks. Our efforts are aimed at trying to improve that stocking success by trying to teach these fish to recognize non-native fish as predators."
Before he releases any native fish into the Colorado River system, O'Neill is scaling up the experiments to larger ponds with longer exposure to predators. He hopes the hatchery trials will show his survival training course works and native fish can learn to avoid predators in the wild.
