How do you control an invasive species–especially a parasitic one–without having to physically remove every specimen from an area? It’s a good question, and a hard one to answer. The ramifications of controlling one animal almost always include serious decline in another, damage and contamination to a habitat and possible immunity in the case of chemical control agents.
In the case of lampreys in the Great Lakes, which attack trout and other fish important to local economies, the answer may be to just freak them right the hell out.
Michael Wagner of Michigan State University exposed a group of lampreys to a mixture of chemicals from putrefying carcasses and ethanol. Another group was subjected to a similar amount of plain ethanol as a control. The animals exposed to the death-scented chemicals jumped out of the tank with a panic-like response.
According to Wagner, repellants could be a better alternative to divert them since even tiny quantities can provoke a response. The smell of death could be used to form a chemical dam to steer lampreys away from environmentally-sensitive waterways. The chemicals could also be used to corral the animals into groups, making them easier to eliminate.
That “panic-like response”? Oh, it’s on video.