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## Green Sturgeon (Acipenser medirostris)
Status | Species Description | Habitat| Distribution | Population Trends | Threats | Conserva t Taxonomy| Key Documents | More Info



## Status ESA Threatened - Southern DPS ESA Species of Concern - Pacific-northern DPS (including coastal spawning populations from th e River north to the Klamath and Rogue rivers) CITES Appendix II - throughout its range 

## Species Description Weight: up to 350 pounds (160 kg) Length: average 4.5-6.5 feet (1.5-2 m), can be as long at 7 feet Appearance: they have no scales, but they have five rows of characteristic bony plates on their bo d called "scutes" Lifespan: 60-70 years Diet: shrimp, mollusks, amphi pods, and small fish Behavior: anadromous; they live primarily in the sea and breed in fresh water Green sturgeon are long-lived, slow-growing fish, and are the most marine-o riented of the sturgeon species. Mature males range fr om 4.5-6.5 feet (1.4-2 m) in "fork length" and do not mature until t h at least 15 years old (Van Eenennaam, 2002), while mature females range from 5-7 feet (1.6-2.2 m length and do not mature until they are at least 17 years old. They can weigh up to 350 pounds (16 0 Maximum ages of adult green sturgeon are likely to range from 60-70 years (Moyle, 2002). Although they are members of the class of bony fishes, the skeleton of sturgeons is composed mo s cartilage. Sturgeon don't have scales, but they have five rows of characteristic bony plates on their called "scutes" . The backbone of the sturgeon curves upward into the caudal fin, forming their sh a tail. On the ventral, or underside, of their fl attened snouts are sensory barbels and a siphon-shape d toothless mouth. Green sturgeon are believed to spend the majority of their lives in nearshore oceanic waters, bays, estuaries. Younger green sturgeon reside in fresh water, with adults returning to freshwater to spa w when they are about 15 years of age and more than 4 feet (1.3 m) in size. Spawning is believed to o every 2-5 years (Moyle, 2002). Adults typically migrate into fresh water beginning in late February, a spawning occurs from March-July, with peak activi ty from April-June (Moyle et al., 1995). Females produce 60,000-140,000 eggs (Moyle et al., 1992). Juvenile green sturgeon spend a few years in f r and estuarine waters before they leave for salt water. They then disperse widely in the ocean. The only feeding data we have on adult gr een sturgeon shows that they are eating "benthic" invertebrates including shrimp, mollusks, amphipods, and even small fish (Moyle et al., 1992). 

## Habitat Green sturgeon utilize both freshwater and saltwater habitat. Green sturgeon spawn in deep pools o Fisheries Home 

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### Green Sturgeon <em>(Acipenser medirostris)</em> :: NOAA Fisheries http://www.fisheries.noaa.gov/ pr/species/fish/green-sturgeon.html

1 of 4 4/21/2016 10:27 AMGreen Sturgeon Critical H a (click for larger view PD F

Green Sturgeon DPS M Image: NOAA (click for larger image) "holes" in large, turbulent, freshwater river mainst ems (Moyle et al., 1992). Specific spawning habitat preferences are unclear, but eggs likely are broadcast over large cobble substrates, but range from clean sand to bedrock substrates as well (Moyle et al., 1995) . It is likely thatcold, clean water is important for proper embryonic development. A dults live in oceanic waters, bays, and estuarie s when not spawning. Green sturgeon are known to forage in estuaries and bays ranging from San Francisco Bay to British Columbia. Critical Habitat In October 2009, NMFS designated critical habitat for the Southern DPS [pdf]. 

## Distribution This species is found along the west coast of Mexi co, the United States, and Canada. Green sturgeon are the most broadly distributed, wide-ranging, and most ma rine-oriented species of the sturgeon family. The green sturgeon ranges from Mexico to at least Al aska in marine waters, and is observed in bays and estuaries up and down the west coast of North America (Moyle et al., 1995). The actual historical and current distribution of wher e this species spawns is unclear as green sturgeon make non-spawning movements into coastal lagoons and bays in the late summer to fall, and because their original spawning distribution may have bee n reduced due to harvest and other anthropogenic effects. Green sturgeon are believed to spawn in the Rog ue River, Klamath River Basin, and the Sacramento River. Spawning appears to rarely occur in the Umpqua River. Green sturgeon in the South Fork of the Trinity River were thought extirpated (Moyle, 2002), bu t juveniles captured at Willow Creek on the Trinity River (Scheiff et al., 2001) suggest that the fish coul d be coming from either the South Fork or the Trinity River (Adams et al., in press). Green sturgeon appear to occasionally occupy the Eel River. 

## Population Trends No good data on current population sizes exists and data on population trends is lacking. Tagging experiments have been conducted irregularly since 19 54, though regular tagging did not occur until 1990. Over 500 green sturgeon have been captured and over 200 have been tagged. 

## Threats The principal factor in the decline of the Southern DPS is: reduction of the spawning area to a limited section of the Sacramento Other threats to the Southern DPS include: insufficient freshwater flow rates in spawning areas, contaminants (e.g., pesticides) bycatch of green sturgeon in fisheries potential poaching (e.g., for caviar) entrainment by water projects influence of exotic species small population size impassable barriers elevated water temperatures 

## Conservation Efforts Fishing regulations and conservation measures represent a reduction in risk to green sturgeon. California, Oregon, Washington (United States) and British Columbia (Canada) have restricted commercial and sport fisheries where green sturgeon occur ( IUCN Red List of Threatened Species ). Recent implementation of sturgeon fishing restrictions in Oregon and Wash ington and protective efforts put in place on the Klamath, Trinity, and Eel Rivers in the 1970s, 19 80s, and 1990s may offer protection to the Southern DPS. The recent closure of the California recreationa l fishery may also provide beneficial to this species. The most important conservation currently occurring is the change in operations of Red Bluff Diversion dam (open from mid September to mid May) allowing access to spawning areas above the dam. Originally, the dam was closed year around. 5 foreign sturgeon spec i listed as endangered in June 2014
. Green sturgeon are anadromous fish. They l primarily in the sea and fresh water. There are 5 other ESA li s sturgeon in the United S shortnose sturgeon, Pal sturgeon, Gulf sturgeon , sturgeon, and Alabama sturgeon. 

### Did You Know? Green Sturgeon <em>(Acipenser medirostris)</em> :: NOAA Fisheries http://www.fisheries.noaa.gov/ pr/species/fish/green-sturgeon.html

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## Regulatory Overview
After completion of a study of its status (Adams et al., 2002) in 2002, NMFS determined that the gr een sturgeon is comprised of two DP S qualify as species under the ESA, but that neither warranted listing as threatened or endangered [pdf] (68 FR 4433). Uncertainties i n structure and status of both DPSs led NMFS to add them to the Species of Concern List[pdf] (69 FR 19975). The "not warranted" determination was challenged in April 2003. NMFS produced an updated status review in February 2005 and pro po the Southern DPS should be listed as threatened under the ESA. NMFS published a final ru le in April 2006 listing the Southern DPS a s threatened [pdf] (71 FR 17757). In September 2008, NMFS proposed critical habitat for the Southern DPS[pdf]. In October 2 009, NMFS published the final rule to designate critical habitat[pdf]. In May 2009, NMFS proposed a 4(d) rule[pdf] to apply ESA take prohibitions to the Southern DPS. NMFS publ ished the final 4(d) rul e 2010. 

## Taxonomy Kingdom: Animalia Phylum: Chordata Class: Osteichthyes Order: Acipenseriformes Family: Acipenseridae Genus: Acipenser Species: smedirostris 

## Key Documents (All documents are in PDF format.) Title Federal Register Date 5-Year Status Review n/a 08/25/2015 Species of concern status review Pa cific-Northern Green Sturgeon DPS n/a 11/20/2014 Initiation of 5-Year Review for the Southern DPS 77 FR 64959 10/24/2012 Final 4(d) Rule to Establish Take Prohibitions 75 FR 30714 06/02/2010 Critical Habitat for the Southern DPS Final Rule 74 FR 52300 10/09/2009 Proposed 4(d) Rule to Establish Take Prohibitions 74 FR 23822 05/21/2009 Proposed Critical Habitat for the Southern DPS 73 FR 52084 09/08/2008 Species of Concern Fact Sheet: Detailed n/a 11/02/2007 Fact Sheet Highlights n/a 05/17/2007

Final ESA Listing Rule for Southern DPS 71 FR 17757 04/07/2006 Proposed ESA Li sting for Southern DPS 70 FR 17386 04/06/2005 Status Review Update (2005) n/a 02/2005
2002 Status Review n/a 06/2002



## More Information NMFS West Coast Regional Office Green Sturgeon Information IUCN Species Information References Adams, P.B., C.B. Grimes, J.E. Hightower, S.T. Lindley, and M.L. Moser. 2002. Stat us Review for the North American green stur g NOAA, National Marine Fisheries Service, Southwes t Fisheries Science Center, Santa Cruz, CA. 49 p. Adams, P.B., C.l. Grimes, J.E. Hightower, S.T. Lindley, M.L. Mose r, and M.J. Parsley. In Press. "Population Status of North Ame r i 

### Green Sturgeon <em>(Acipenser medirostris)</em> :: NOAA Fisheries http://www.fisheries.noaa.gov/ pr/species/fish/green-sturgeon.html

3 of 4 4/21/2016 10:27 AMGreen Sturgeon, Acipenser medirostris " Environmental Biology of Fishes. Beamesderfer, R.C.P. and M.A.H. Webb. 2002 Green sturgeon status review info rmation. S.P. Cramer and Associates, Gresham U.S. Moyle, P.B., P.J. Foley, and R.M. Yoshiyama. 1992. Status of green sturgeon, Acipensermedirostris , in California . Final Report s u to National Marine Fisheries Service. 11 p. University of California, Davis, CA 95616. Moyle, P.B., R.M. Yoshiyama, J.E. Williams , and E.D. Wikramanayake. 1995. Fish Species of Special Concern in California. Sec o edition. Final report to CA Departm ent of Fish and Game, contract 2128IF. Moyle, P.B. 2002. Inland fishes of California. Un iversity of California Press, Berkeley, CA. 502 pp. Scheiff, A.J., J.S. Lang, W.D. Pinnix. 2001. Juvenile salmonid m onitoring on the mainstem Klamath River at Big Bar and mainste River at Willow Creek 1997-2000. USFWS, AFWO, Arcata, CA 95521, 114 pp. Van Eenennaam, J. P. 2002. Personnel Communication. In Adams, P.B., C.B. Grimes, J.E. Hightower, S.T. Lindley, and M.L. Mo s Status Review for the North American gre en sturgeon. NOAA, National Marine Fisherie s Service, Southwest Fisheries Science C Santa Cruz, CA. 49 p. Updated: August 25, 2015

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### Green Sturgeon <em>(Acipenser medirostris)</em> :: NOAA Fisheries http://www.fisheries.noaa.gov/ pr/species/fish/green-sturgeon.html

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