Interesting question! I'd guess, however you do it, you could only achieve a temporary uptick in the population. Like any other predator/prey relationship, the ecosystem can only support X predators. After all, the ancient Egyptians could only have so many cats around until they ran out of mice.

Be a pain to breed. They stay underwater as nymphs for 2 years, and that's 2 years where you gotta keep them from being someone else's lunch.