The bighead carp, shown here, which can grow to be larger than a beagle, is one of four species of Asian carps that threaten to invade the Great Lakes, including Lake Erie. Scientists say the fish, if they get in, could do significant damage. “Once an aquatic invasive species becomes established, eradication ranges from difficult and costly to impossible,” says Eugene Braig, aquatic ecosystems program director for OSU Extension. “Prevention is key.” Read more. (Photo: Asian Carp Regional Coordinating Committee.)