The ancient vampire fish that accidentally collapsed a massive North American fishing industry

Nature · Published 3 October 2026 Swipe more like this →

In short: The sea lamprey is a primitive, jawless predator that has haunted Atlantic waters for eons. While native to the ocean, its accidental introduction into the Great Lakes via human-made canals triggered an ecological disaster, decimating commercial fish stocks and forcing a century-long battle to control its unchecked, parasitic spread.

Resembling an eel but lacking scales, fins, and gill covers, the sea lamprey is a biological relic. Its skeleton is composed entirely of cartilage, similar to sharks. This creature is anadromous, meaning it spends its adult life in the sea or large lakes before migrating into freshwater rivers to spawn. Once it finds a suitable gravel bed, it lays eggs and dies shortly thereafter. The offspring, known as ammocoetes, burrow into river silt and filter-feed for several years before undergoing a metamorphosis that prepares them for a predatory life in open water.

The lamprey’s efficiency as a killer stems from its specialized anatomy. It possesses a circular, sucker-like mouth lined with rows of sharp, keratinized teeth. By latching onto a host fish, it uses a rasping, tongue-like organ to penetrate the flesh and feed on blood and body fluids. A single adult can consume approximately 40 pounds of fish during its feeding cycle. Because they are highly tolerant of varying salinities and can process toxic substances like urea from their prey, they are exceptionally resilient survivors in diverse environments.

The species became a notorious invasive threat in the 1830s after the completion of the Welland Canal, which bypassed natural barriers like Niagara Falls. Within a decade, lampreys had infiltrated all five Great Lakes. By the 1930s, they had effectively destroyed a trout fishery that once yielded 10 million pounds of fish annually. Today, the Great Lakes Fishery Commission manages their numbers using specialized traps, barriers, and lampricides—chemicals that target larvae without harming other aquatic life. Scientists are even replicating the pheromones lampreys use to communicate, turning the predator's own biology against it to curb further destruction.

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