• Family: Petromyzontidae (Northern lampreys)
• Other Names: Lamprey
• Ohio Status: No special status
• Adult Size: Typically 10-14 inches, can reach 15 inches.
• Typical Foods: As ammocoetes they filter feed algae, plankton, and other organic matter. Adults are parasitic on larger fish species.
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 silver lamprey has a single continuous dorsal fin. They have 50-56 myomeres (muscle segments) between the last gill opening and the anus. The disc like mouth of the adults contains large teeth across most of the oral disk. The teeth around the mouth have only a single point to each one, hence the species name of unicuspis. Adults are light tan or silvery tan color. During spawning, adults become blue-black in color. The silver lamprey differs from the Ohio lamprey and mountain brook lamprey by having only single pointed rather than bicuspid, or 2 points on their teeth around the mouth, and a lower average myomere count between the last gill opening and the anus. Additionally the mountain brook lamprey is non-parasitic. Northern brook lampreys only have clearly visible teeth in the center of the oral disc and are non-parasitic. All other Ohio lamprey species have 2 separate dorsal fins.
Habitat and Habits
All parasitic lampreys required three distinctly different habitats that are connected by free flowing (free of dams) stretches of streams. Spawning adults are found in clear brooks with fast flowing water and either sand or gravel bottoms. Juveniles or ammoccoetes are found in slow moving water buried in soft substrate of medium to large streams. Non-spawning parasitic adults are found in large bodies of water (Lake Erie or the Ohio River) with abundant populations of large fish. Silver lampreys were historically very abundant in Lake Erie and its tributaries. They likely were also more numerous in the Ohio River and its tributaries. Today they can still be found in both Lake Erie and the Ohio River and spawning runs are made up tributaries, however they are much less numerous than in the past.
Reproduction and Care of the Young
Silver lampreys spawn in late May or early June 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 parasitic adult in spring. Adults migrate into the Ohio River or Lake Erie and feed on other fish. The following spring they migrate into tributary streams spawn and then die shortly after.