Fish
Green Sturgeon
Acipenser medirostris · also called green sturgeons
Far out in Pacific coastal waters, a green sturgeon spends most of its long life roaming the open ocean, returning to freshwater only when the time comes to journey up one of a small handful of specific rivers to spawn.
Overview
The green sturgeon, Acipenser medirostris, is a large, ancient fish native to Pacific coastal waters from Alaska to Mexico, entering a small number of specific rivers along the coast of California and Oregon to spawn. Its unusually marine-oriented lifestyle, dependence on just a handful of critical spawning rivers, and slow, long-lived life history make it one of the more ecologically distinctive and conservation-relevant sturgeon species in North America.
A fish of the ocean that needs just a few rivers
While the green sturgeon roams a vast stretch of Pacific coastline for most of its life, its entire future as a species hinges on the continued health of only a small number of specific rivers it returns to for spawning.
Status
Near Threatened, having declined in parts of its range due to dam construction, water diversion, and other alterations affecting its critical spawning rivers.
Green Sturgeon: common questions
Why is the green sturgeon considered more marine than other sturgeon species?
This species spends the great majority of its adult life in the open ocean, returning to freshwater rivers only when it is time to spawn, a lifestyle considerably more marine-oriented than most other North American sturgeon species, which tend to spend more time in freshwater or estuarine habitat throughout the year.
Why is the green sturgeon vulnerable even though it ranges across a huge stretch of ocean?
Despite its broad ocean-going range from Alaska to Mexico, this species returns to spawn in only a small number of specific river systems, meaning dam construction, water diversion, or other disturbance affecting just a few critical rivers can significantly impact the species' ability to reproduce, regardless of how much ocean habitat remains available.
How long does a green sturgeon live?
This species can live for several decades and takes many years to reach sexual maturity, a slow life history typical of sturgeon generally that makes population recovery particularly difficult once numbers decline, since replacing lost individuals takes considerably longer than for faster-reproducing fish species.
What does a green sturgeon look like?
This species is covered in rows of bony plates called scutes rather than typical fish scales, an ancient body armour shared across all sturgeon species, giving it a distinctive, almost prehistoric appearance that reflects the sturgeon family's very long evolutionary history.