Despite the coordinated efforts of the United States and Canada, about 400,000 invasive sea lampreys inhabit the Great Lakes, according to Great Lakes Echo.
Researchers and restoration leaders say that several factors are inhibiting sea lamprey reduction projects. As water quality improves in nearby streams and rivers, sea lamprey infestations are growing. Additionally, dams in the area are degrading, creating new routes for the lampreys to enter the lakes.
Sea lampreys are native to the Atlantic Ocean, but have lived in the Great Lakes since the 1920s. Lake Erie has the lowest population of all the Great Lakes, but that number shows signs of growing.
Image: Sea lamprey (Credit: USFWS Pacific, via Flickr)