Bancales and their predators have evolved together for centuries. Whenever one starts winning, the other evolves to maintain equilibrium.
Then some 1980s bancales hitchhiked on two time travelling Sperm Whales. Their predators having long since evolved past being able to keep their numbers in check were unable to stop the population explosion.
James T. Kirk is responsible for an ecological disaster greater than that caused by the probe that started all this.