Answer:
Build a canal linking the two ponds that permits free movement of mosquitofish, but not of predators.
Explanation:
On the Bahaman island of Andros mosquitofish populations live in various, now isolated, freshwater ponds that were once united. Currently some predator-rich ponds have mosquito fish that can swim in short, fast bursts, while other predator-poor ponds have mosquito fish that can swim continuously for a long time. When placed together in the same body of water, the two kinds of female mosquito fish exhibit exclusive breeding preferences.
