Managing invasive species involves killing individual animals to protect native ecosystems. This creates ethical tension between ecosystem welfare and individual animal welfare that requires careful policy consideration.
The invasive species welfare dilemma involves genuine ethical complexity. Grey squirrels, mink, and American signal crayfish are sentient animals capable of suffering, yet their unchecked spread causes the extinction or severe suppression of native species - a much larger total welfare harm. The utilitarian case for control is strong when methods are humane. Fenn traps, drowning cage traps, and poorly administered poisons cause prolonged suffering and should be replaced by more humane alternatives. Contraception research for grey squirrels offers a future path that avoids this dilemma.