Ethical aspects and dilemmas of fertility control of unwanted wildlife: an animal welfarist's perspective.

Proposals to manipulate the fertility of wild, free-living animals extend the domination humans already exercise over domesticated animals. Current lethal methods for population control include poisoning, trapping, hunting, dogging, shooting, explosives, fumigants, and deliberately introduced disease. Animal welfare interests are based on individual animal suffering, but those interests are often overshadowed by labelling of groups of animals as pests, resource species, national emblem or endangered species. Public concern for animal welfare and acceptance of new population control methods will be influenced by such labels. The animal welfare implications of new population control technology must be balanced against the existing inhumane lethal methods used. It will be difficult to resolve the dilemma of a mechanism for disseminating a fertility control agent that will cause some animal suffering (e.g. a genetically-manipulated myxoma virus for European rabbits), yet may reduce future rabbit populations and therefore the number suffering from lethal methods. An Animal Impact Statement is proposed as a tool to assist debate during development of fertility control methods and for decision making prior to their use. A comprehensive and objective Animal Impact Statement may introduce an ethic that moves the pendulum from attitudes that allow sentient animals to be destroyed by any and all available means, towards a more objective selection of the most effective and humane methods.