STATUS

ESA Threatened - Southern DPS
ESA Species of Concern - Pacific-northern DPS (including coastal spawning populations from the Eel River north, to the Klamath and Rogue rivers)

DISTRIBUTION

Of the 8 North American species of sturgeon, green sturgeon are the widest ranging.  They also spend more time in marine environments than the other sturgeon species, and only move into the rivers to spawn.  They range from the west coast of Mexico, the U.S., and Canada, and have been found in estuaries and bays all along the west coast.

Green sturgeon that spawn and live in the Sacramento River, Sacramento-San Joaquin Delta, and the San Francisco Bay Estuary were listed as a threatened species (ESA) in 2006.  Populations specific to that region have deteriorated as a result of dams, overfishing, loss of habitat, pollution, and other anthropogenic effects.

See the interview with Pat Foley, PhD Evolutionary Genetics, Conservation Biology



HISTORY

Green sturgeon are an ancestral species that predate the dinosaurs. They have remained relatively unchanged to this day.  Their color ranges from olive green, to gray or golden brown.  They are a long-lived, late maturing species that spawn periodically which makes them susceptible to overfishing. 

CHARACTERISTICS

• Mature males range from 4.5-6.5 feet (1.4-2m), and do not reach sexual maturity until they are at least 15 years old.  Mature females range from 5-7 feet (1.6-2.2m), and do not reach sexual maturity until they are at least 17 years old.
  
• They can live 60-70 years.
• They have a heterocercal tail much like that of sharks.
• They have a torpedo shaped body, and sloping head.
• They do not have scales, rather they are armored with several lengthwise rows of bony plates called scutes.
• The have 4 barbels that dangle just in front of the mouth.  The barbels serve as sensory organs for finding invertebrates in the benthic food chain.
• They have a rubbery siphon-like mouth that acts like a vacuum for picking up food off the bottom.
  
• Their diet consists primarily of small fish, mussels, shrimp, crabs, worms, amphipods, and isopods.