The American bullfrog (scient. Rana catesbeiana) is endemic to the Americal State of California and is widely used for the production of frog legs. However, in 2000 a businessman from Chania, who bred bullfrogs was disappointed by his investment and released all his frogs into the Lake Agia. This resulted in the complete displacement of the local Cretan frogs from the lake.
The bullfrog is 4 times greater (reaches a weight of 200gr) than the Cretan frog (40gr) and is very aggressive. It can kill other aquatic organisms, such as smaller frogs and even birds! The biggest problem is that lake Agia does not host a natural enemy so to stop its rapid spread.