Pacific lamprey

Pacific Lamprey

Pacific lamprey facing right

The Pacific lamprey (Entosphenus tridentatus) is a species of lamprey found along the Pacific Coast of North America and Asia. It is an anadromous species, meaning it migrates from the ocean to freshwater rivers and streams to spawn. The Pacific lamprey is known for its distinctive eel-like body and its parasitic feeding habits during its adult stage.

Description

The Pacific lamprey has a long, slender body that can grow up to 80 cm in length. Its skin is smooth and scaleless, and it has a series of seven gill openings on each side of its head. The mouth of the lamprey is circular and filled with sharp, keratinous teeth, which it uses to attach to host fish and feed on their blood and bodily fluids.

Life Cycle

Ammocoetes held by biologist

The life cycle of the Pacific lamprey includes several distinct stages. It begins as an egg, which hatches into a larval stage known as an ammocoetes. The ammocoetes live buried in sediment in freshwater streams for several years, where they filter feed on detritus and microorganisms. After this larval stage, they undergo a metamorphosis into the juvenile stage, known as a macropthalmia, and migrate to the ocean.

In the ocean, the Pacific lamprey becomes parasitic, attaching to host fish and feeding on their blood. After one to three years in the ocean, the lamprey returns to freshwater to spawn. Spawning occurs in gravel beds in streams, where the adults construct nests. After spawning, the adults die, completing their life cycle.

Habitat and Distribution

Lamprey at Bonneville Dam

Pacific lampreys are found along the Pacific Coast from Japan to Mexico. They inhabit both marine and freshwater environments, spending part of their life in the ocean and part in rivers and streams. They are known to migrate significant distances to reach their spawning grounds, often overcoming obstacles such as dams and waterfalls.

Ecological Role

The Pacific lamprey plays a crucial role in its ecosystem. As a parasitic species, it helps control the populations of its host fish. Additionally, the nutrients from decomposing adult lampreys provide important resources for stream ecosystems. The ammocoetes also contribute to the ecosystem by filtering organic material from the water.

Conservation

Lamprey caught in a net

The Pacific lamprey faces several threats, including habitat loss, pollution, and barriers to migration such as dams. Conservation efforts are underway to improve passage for lampreys at dams and to restore their habitats. These efforts are crucial for maintaining the ecological balance and cultural significance of the species.

Cultural Significance

The Pacific lamprey holds cultural importance for many Indigenous peoples along the Pacific Coast. It is a traditional food source and is used in various cultural practices. Efforts to conserve the lamprey are often closely tied to preserving these cultural traditions.

Related Pages

• Lamprey
• Anadromous fish
• Ecosystem
• Conservation biology