Scientific name: Lampetra appendix
Identification: American brook lamprey are freshwater, small sized, eel-like fish that are about 6.5 inches long on average. They are olive in color and have a white underbelly, and they are often confused with American eels. Instead of having well-developed teeth arranged in concentric rings like sea lampreys do, American brook lampreys have blunt teeth arranged in pairs, indicating that they are non-parasitic to fish.
Habitat: American brook lamprey live in cold, clear streams and rivers that are smaller in size. In New Hampshire, brook lampreys have only been found in the Oyster River, preferring to stay in the open wetland areas of the river.
Overview: American brook lampreys are considered to be critically imperiled in New Hampshire and are endangered in other New England states. They are vulnerable to human activity and are a good indicator of water quality, which means that the Oyster River must be well maintained in order to prevent extirpation. These lampreys spend most of their lives in the larval stage before maturing at around 5 years old and then dying after metamorphosis.