The frogs over there were some Caribbean species of Eleutherodactylids, including the Coqui from Puerto Rico. Not causing any ecological problems when last I checked; they mostly lived in areas where native Hawaiian fauna was pretty well wiped out. So the only problem was the noise. I also seem to recall that the part of the Big Island where they lived was famous for growing, ahem, agricultural crops which allowed one to sleep through just about anything…

Good news is, Hawai’i has no native amphibians (and almost no mammals or reptiles either). So if you could find an amphibian-specific pathogen, say the fungus that allegedly wiped out the Golden Toad, the Gastric-breeding Frog, and various other anurans worldwide, you could probably use it over there without much fear of unintended consequences. Much safer than using fish or snakes, which would probably decide that the endemic Hawaiian fish and insects tasted better than the exotic treefrogs. But I don’t think that fungus has been cultured for commercial use yet.

Cheers,

Josh