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Marine Animal Encyclopedia

Sea Lamprey Petromyzon marinus

With its long, cylindrical body, the sea lamprey might at first be mistaken for an eel, but closer inspection reveals differences. Unlike eels, the sea lamprey has no jaws. Its body is flattened toward the tail and it has two dorsal fins. Its circular mouth lies beneath the head, and is surrounded by a frill of tiny skin extensions. Inside the mouth, the teeth are arranged in numerous concentric arcs, which helps to distinguish it from the similar, but smaller, lampern. As a mature adult, the sea lamprey has dark mottling on its back. Adults live at sea and feed on dead or netted fish as well as attacking a wide variety of live ones. It uses a “sucker” to attach to its host, scrapes a hole through the skin, and sucks out flesh and fluids. It spawns in rivers and the larvae remain in fresh water for about five years before they mature and move out to sea. This species is now rare as a result of trapping, intentional poisoning, and the degradation of its river habitat.

Sea Lampreyzoom image
  • Class Petromyzontida
  • Length Up to 4 ft (1.2 m)
  • Weight Up to 5 lb (2.5 kg)
  • Depth 3–2,100 ft (1–650 m)
  • Distribution Coastal temperate waters of, and rivers adjacent to, north Atlantic