Atlantic Sturgeon
Acipenser oxyrinchus oxyrinchus
Profile / Morphology 2
Atlantic sturgeon are bluish black or olive brown dorsally with paler sides and a white ventral surface. They have five major rows of dermal scutes. According to Collette and Klein-MacPhee (2002), Atlantic sturgeon can be distinguished from the endangered shortnose sturgeon by their larger size, small mouth, presence of bony scutes between the anal fin base and the lateral scute row. Atlantic sturgeon also have a double row of dorsal scutes behind the dorsal fin, a double row of scutes before the anal fin, and the presence of a pale intestine.
Diet 2
Bottom invertebrates including mussels, worms, and shrimps
Average lifespan in the wild 2
up to 60 years
Size / Weight 2
14 feet (maximum) / 800 lb (maximum)
Habitat 2
These fish are primarily bottom-oriented feeders, generally over soft sediments, as their prey items generally live in the sediment. Sturgeon are also known to breach or jump from the water which indicates that at times, they can be found in the upper water column. This occurs when they are susceptible to harm from ship strikes. Atlantic sturgeon are euryhaline, meaning they do not spend a large part of their life in estuaries, and migrate between the sea and freshwater.
Range 2
Historically, Atlantic sturgeon were present in approximately 38 rivers in the United States from St. Croix, Maine to the Saint Johns River, Florida. 35 rivers have been confirmed to have had a historical spawning population. Atlantic sturgeon are currently present in 35 rivers, and spawning occurs in at least 20 of these rivers (NMFS, unpublished).
Reproductive / Life Span 2
The Atlantic sturgeon is an anadromous species. 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 only spawn every 1 to 5 years for males (Smith 1985, Collins et al. 2000, Caron et al. 2002) and 2 to 5 years for females (Vladykov and Greeley 1963, Van Eenennaam et al. 1996, Stevenson and Secor 1999). Fecundity of Atlantic sturgeon is related to age and body size, and ranges from 400,000 to 8 million eggs (Van Eenennaam and Doroshov 1998, Dadswell 2006).
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 quickly move downstream and inhabit brackish waters for a few months to year. At approximately 30 to 36 inches TL (76-92 cm), they move into coastal waters. Tagging data indicate that immature Atlantic sturgeon travel widely once they leave their birth rivers.
In general, atlantic sturgeon populations show latitudinal variation with faster growth and earlier age at maturation in more southern areas. For example, they mature in South Carolina at 5 to 19 years of age, in the Hudson River at 11 to 21 years (Young et al. 1998), and in the Saint Lawrence River at 22 to 34 years (Scott and Crossman 1973).
Atlantic sturgeon have been aged to 60 years (Mangin 1964); however this should be taken as an approximation age.
Relatives 2
Atlantic sturgeon are members of the sturgeon family which contains over 30 similar looking species throughout the Northern hemisphere. Sturgeons are famous for their eggs, which are called caviar and vary in value according to species of origin.
Found in the following Estuarine Reserves 2
Wells (ME), Great Bay (NH), Waiquoit Bay (MA), Narragansett Bay (RI), Hudson River (NY), Jacques Cousteau (NJ), Delaware, Chesapeake Bay (MD and VA), North Carolina, N. Inlet-Winyah (SC), ACE Basin (SC), Sapelo Island (GA), and Guano Tolomato Matanzas (FL)
Water quality factors needed for survival 2
Water Temperature: between 13 and 17 °C
Turbidity: low
Water Flow: optimal for spawning is 0.46 to 0.76 m/s
Salinity: euryhaline - spawn in freshwater streams, adults live in ocean
Dissolved Oxygen: 3.5 mg/L minimum and better to be above 5mg/L
Threats 3
Major Threats
Conservation notes 2
Bycatch of Atlantic sturgeon has been reported in many different fisheries conducted in rivers,
estuaries, the nearshore ocean, and the Exclusive Economic Zone throughout it’s range. Bycatch losses principally occur in sink-net fisheries, but may be occurring in substantial numbers in trawl fisheries (Atlantic Sturgeon Status Review Team 2007). The fisheries of most concern are the weakfish-striped bass fishery, northern kingfish, American shad, southern flounder, red hake and shrimp trawl fisheries.
A variety of specific habitat degradation causes are identified by river system in the most recent status review (Atlantic Sturgeon Status Review Team 2007).
Importance to Humans and Estuaries
Cultured Atlantic sturgeon continue to be a valued commercial fish for both its flesh and their eggs (roe). In many areas, atlantic sturgeon occurred in high numbers. Due to their migratory lifestyle, they were a significant source of nutrients being brought into and out of estuaries.
How to Help Protect this Species
Atlantic sturgeon use estuaries and freshwater areas. They are susceptible to water pollution and damage to and alteration of stream channels and riparian zones. Therefore, efforts to protect the species include:
•Minimize runoff of neighborhood pollutants, fertilizer, and sediment into local streams are helpful to this species, and other estuary dwelling species.
•Join a stream or watershed advocacy group in your area to protect your local estuary ecosystems.
•Advocate the implementation of effective fish passage solutions so fish can bypass dams and artificial barriers.
•Support restoration of more natural water flow regimes.
Support the following:
•Organizations involved with Atlantic sturgeon conservation (state and local governments, private and conservation organizations, including the Hudson River Foundation)
•Conservation programs like the Species of Concern program and other non-governmental organization programs.
•Long-term monitoring programs for most of the subpopulations to help determine the status of the species (e.g., whether it is decreasing, increasing, or remaining stable).
Except for the Hudson and Altamaha rivers subpopulations, spawning population abundance estimates are needed for the extant reproducing populations. Also, locations of spawning and nursery grounds need to be identified for most of the subpopulations. Accurate estimates of bycatch and bycatch mortality are needed to determine the magnitude of this threat. Also information on contaminant levels in Atlantic sturgeon is needed.
Sources and Credits
- (c) Noel Burkhead, some rights reserved (CC BY-NC-SA), https://www.flickr.com/photos/51614465@N08/4752052738/
- (c) GTMResearchReserve, some rights reserved (CC BY-SA)
- Adapted by GTMResearchReserve from a work by (c) International Union for Conservation of Nature and Natural Resources, some rights reserved (CC BY-NC-SA), http://eol.org/data_objects/30916289
