Northern Brook Lamprey
• Family: Petromyzontidae (Northern Lampreys)
• Other Names: Lamprey
• Ohio Status: Endangered
• Adult Size: Typically 4-6 inches, can reach 7 inches.
• Typical Foods: Organic matter and microscopic organisms.
All lampreys have a long eel-like body and no scales. They have segments of muscles that are visible along their body called myomeres, and a jawless mouth. In larval lampreys, called ammocoetes, their mouth is not fully developed, very small, and hidden between folds of skin. Adults have a disk shaped mouth with varying amounts of teeth depending on the species. The northern brook lamprey has a single continuous dorsal fin, not separated into two distinct parts. They have 47-56 myomeres (muscle segments) between the last gill opening and the anus. The disc like mouth of the adults contains only single pointed teeth around the mouth. Teeth on the outer portion of the disc are very small and difficult to see. Adults are a light tan or silvery tan in coloration prior to spawning. During spawning, adults become blue-black in color. The northern brook lamprey differs from the moutain brook lamprey by having teeth with single (rather than double) points and a lower myomere count. Silver and Ohio lampreys are larger and parasitic on larger fish as adults. All other Ohio lamprey species have 2 separate dorsal fins.
Habitat and Habits
All non-parasitic lampreys required two distinctly different habitats that are connected by free flowing (free of dams) stretches of streams. Adults are found in clear brooks with fast flowing water and either sand or gravel bottoms. Juveniles or ammocoetes are found in slow moving water buried in soft substrate of medium to large streams. Northern brook lampreys have been found in the Grand and St. Joeseph Rivers in the Lake Erie drainage and several tributaries to the Scioto River in the Ohio River drainage. However, they have only been found in the upper Grand River in recent years.
Reproduction and Care of the Young
Northern brook lampreys spawn in early May in shallow pits that are excavated near the upper ends of gravel riffles. These pits are created communally by several individuals constructing one pit. They use their suction cup like mouth to move stones away to form the pit. Females then deposit many eggs in these pits. After hatching, the ammocoetes (larval stage of lampreys) drift down stream to larger slower moving streams and burrow into the sediment. During this phase, they eat organic particles strained from bottom sediments and the water, as well as microscopic organisms. After several years, the ammocoetes transform into a non-parasitic adult in the late summer or fall. Adults migrate into smaller streams and do not feed. The following spring they spawn and then die shortly after.