Atlantic Sturgeon (Acipenser oxyrinchus oxyrinchus)
Atlantic sturgeon (top) and Shortnose sturgeon (bottom)
(Acipenser oxyrinchus and Acipenser brevirostrum)
Photo: Doug Cooke,
South Carolina Department of Natural Resources
Did You Know?
· WildEarth Guardians and Friends of Animals Petition to List 15 Foreign Sturgeon Species under the ESA [pdf]
ESA Threatened - 1 "distinct population segment"
(1) Gulf of Maine DPS*
ESA Endangered - 4 "distinct population segments"
(1) New York Bight DPS*
(2) Chesapeake Bay DPS*
(3) Carolina DPS*
(4) South Atlantic DPS*
CITES Appendix II - throughout its range
Gulf sturgeon (Acipenser oxyrinchus desotoi) is another subspecies of A. oxyrinchus.Species Description
|Weight:||up to 800 lbs (370 kg)|
|Length:||14 feet (4.3 m)|
|Appearance:||bluish-black or olive brown with paler sides and a white belly; they have 5 major rows of "scutes"|
|Diet:||crustaceans, worms, and mollusks|
|Behavior:||they migrate upriver in spring in spawn|
The Atlantic sturgeon is a long-lived, estuarine dependent, anadromous fish. Atlantic sturgeon can grow to approximately 14 feet (4.3 m) long and can weigh up to 800 lbs (370 kg). They are bluish-black or olive brown dorsally (on their back) with paler sides and a white belly. They have five major rows of dermal "scutes".
Atlantic sturgeon are similar in appearance to shortnose sturgeon (Acipenser brevirostrum), but can be distinguished by their larger size, smaller mouth, different snout shape, and scutes.
Atlantic sturgeon have been aged to 60 years. There is generally faster growth and earlier age at maturation in more southern populations. For example, Atlantic sturgeon mature in South Carolina rivers at 5 to 19 years of age, in the Hudson River at 11 to 21 years, and in the Saint Lawrence River at 22 to 34 years.
Spawning adults migrate upriver in spring, beginning in February-March in the south, April-May in the mid-Atlantic, and May-June in Canadian waters. In some areas, a small spawning migration may also occur in the fall. Spawning occurs in flowing water between the salt front and fall line of large rivers. Atlantic sturgeon spawning intervals range from 1 to 5 years for males and 2 to 5 years for females. "Fecundity" of female Atlantic sturgeon is correlated with age and body size and ranges from 400,000 to 8 million eggs. The average age at which 50% of maximum lifetime egg production is achieved is estimated to be 29 years, which is approximately 3 to 10 times older than for other bony fish species.
Following spawning, males may remain in the river or lower estuary until the fall; females typically exit the rivers within four to six weeks. Juveniles move downstream and inhabit brackish waters for a few months and when they reach a size of about 30 to 36 inches (76-92 cm) they move into nearshore coastal waters. Tagging data indicate that these immature Atlantic sturgeon travel widely once they emigrate from their natal (birth) rivers.
Atlantic sturgeon are benthic feeders and typically forage on "benthic" invertebrates (e.g. crustaceans, worms, mollusks).
Atlantic sturgeon are "anadromous"; adults spawn in freshwater in the spring and early summer and migrate into "estuarine" and marine waters where they spend most of their lives. In some southern rivers a fall spawning migration may also occur. They spawn in moderately flowing water (46-76 cm/s) in deep parts of large rivers. Sturgeon eggs are highly adhesive and are deposited on bottom substrate, usually on hard surfaces (e.g., cobble). It is likely that cold, clean water is important for proper larval development. Once larvae begin migrating downstream they use benthic structure (especially gravel matrices) as refuges. Juveniles usually reside in estuarine waters for months to years.
Subadults and adults live in coastal waters and estuaries when not spawning, generally in shallow (10-50 m depth) nearshore areas dominated by gravel and sand substrates. Long distance migrations away from spawning rivers are common.
Historically, Atlantic sturgeon were present in approximately 38 rivers in the United States from St. Croix, ME to the Saint Johns River, FL, of which 35 rivers have been confirmed to have had a historical spawning population. Atlantic sturgeon are currently present in approximately 32 of these rivers, and spawning occurs in at least 20 of them.
Studies have consistently found populations to be genetically diverse and indicate that there are between 7 and 10 populations that can be statistically differentiated. However, there is some disagreement among studies, and results do not include samples from all rivers inhabited by Atlantic sturgeon. There are only two Atlantic sturgeon populations for which size estimates are available - the Hudson River and the Altamaha River populations. In 1995, sampling crews on the Hudson River estimated that there were 9,500 juvenile Atlantic sturgeon in the estuary. Since 4,900 of these were stocked hatchery-raised fish, about 4,600 fish were thought to be of wild origin. The mean annual spawning stock size (spawning adults) was estimated at 870 (600 males and 270 females). The Altamaha River supports one of the healthiest Atlantic sturgeon populations in the Southeast, with over 2,000 subadults captured in research surveys in the past few years, 800 of which were 1 to 2 years of age. The population appears to be stable.
led to wide-spread declines in Atlantic sturgeon abundance
- A large U.S. commercial fishery (100,000-250,000 lbs/yr) existed for Atlantic sturgeon from the 1950s-1990s, though the origin of the fishery dates back to colonial times.
- However, since the 1998 harvest moratorium there have been few surveys to assess status and abundance.
Current threats include:
- "bycatch" of sturgeon in fisheries targeting other species
- habitat degradation and loss from various human activities such as dredging, dams, water withdrawals, and other development
- habitat impediments including locks and dams (e.g., Cape Fear and Santee-Cooper Rivers )
- ship strikes (e.g., Delaware and James Rivers).
Although there are no known diseases threatening Atlantic sturgeon populations, there is concern that non-indigenous sturgeon pathogens could be introduced through aquaculture operations.
The Atlantic sturgeon is managed under a Fishery Management Plan implemented by the Atlantic States Marine Fisheries Commission (ASMFC). In 1998, the ASFMC instituted a coast-wide moratorium on the harvest of Atlantic sturgeon, which is to remain in effect until there are at least 20 protected age classes in each spawning stock (anticipated to take up to 40 or more years). NMFS followed the ASMFC moratorium with a similar moratorium for Federal waters. Amendment 1 to ASMFC's Atlantic sturgeon Fishery Management Plan also includes measures for preservation of existing habitat, habitat restoration and improvement, monitoring of bycatch and stock recovery, and breeding/stocking protocols.
In 2009, the Natural Resources Defense Council (NRDC) petitioned NMFS to list the Atlantic sturgeon under the ESA. NOAA’s Fisheries Service made a final decision to list five distinct population segments of Atlantic sturgeon under the Endangered Species Act in response to this petition. The Chesapeake Bay, New York Bight, Carolina, and South Atlantic populations of Atlantic sturgeon will be listed as endangered, while the Gulf of Maine population will be listed as threatened.
In 2003, a workshop sponsored by NMFS and U.S. Fish and Wildlife Service was held to review the status of Atlantic sturgeon. The workshop attendees concluded that some populations seemed to be recovering while other populations continued to be depressed. As a result, NMFS initiated a second status review of Atlantic sturgeon in 2005 to reevaluate whether this species required protection under the ESA. That status review was completed in 2007.
|Final Listing Rule for South Atlantic and Carolina Distinct Population Segments of Atlantic Sturgeon in the Southeast Region||77 FR 5914||02/06/2012|
|Final Listing Rule for Gulf of Maine, New York Bight, and Chesapeake Bay Distinct Population Segments of Atlantic Sturgeon in the Northeast Region||77 FR 5880||02/06/2012|
|NMFS proposes protective regulations under the ESA for Gulf of Maine DPS (Proposed 4(d) rule)||76 FR 34023||06/10/2011|
|Proposed Listings for Two Distinct Population Segments in the Southeast region||75 FR 61904||10/6/2010|
|Proposed Listings for Three Distinct Population Segments in the Northeast Region||75 FR 61872||10/6/2010|
|Species of Concern Fact Sheet: Detailed||n/a||02/23/2010|
|NMFS Accepts NRDC Petition to List Atlantic Sturgeon under the Endangered Species Act (90-Day Finding on a Petition)||75 FR 838||01/06/2010|
|NRDC Petition to List Under the ESA||n/a||09/30/2009|
|Status Review (2007)||n/a||02/23/2007|
|Notice of Addition to Candidate Species List||71 FR 61022||10/17/2006|
Updated: December 5, 2012