Shortnose sturgeon
Acipenser brevirostrumProfile / Morphology 1
Shortnose sturgeon are moderately large, bottom oriented anadromous fish. The shortnose sturgeon shares the same general external shape of all sturgeon. Their snout is somewhat elongated and bladelike with 4 barbels (sensory “whiskers”) in front of the mouth. Similar to most sharks, the upper lobe of the tail is longer than the lower lobe. Like most sturgeon, they are characterized by unique arrangements of armored plates along their sides and back, called scutes.
The shortnose sturgeon is the smallest of the three sturgeon species that occur in eastern North America, having a maximum known total length of 4.5 feet (143 cm). Growth rate and maximum size vary with latitude, with the fastest growth occurring among southern populations. Sex ratio among young adults is 1:1, but changes to a predominance of females (4:1) for fish larger than 3 feet (90 cm). Shortnose and Atlantic sturgeon occur in the same areas. Shortnose sturgeon may be distinguished from the Atlantic sturgeon on the basis of mouth width, versus inter-eye width, scute patterns, and snout length.
Diet 2
Juveniles are believed to feed on benthic insects and crustaceans in streams. Mollusks and large crustaceans are the primary food of adult shortnose sturgeon.
Average lifespan in the wild 2
67 years (max for female), 30 years (max for males)
Size / Weight 2
4.5 feet (adult female maximum) / 50 lb (maximum)
Habitat 2
Shortnose sturgeon is an anadromous fish that spawns in the coastal rivers along the east coast of North America. They prefer the nearshore marine, estuarine and riverine habitat of large river systems. Unlike other anadromous fish in the region, such as shad or salmon, they do not appear to make long distance offshore migrations, and spend most of their time in their birth river, rarely venturing to the ocean. They are benthic feeders, so benthic substrate type is key to their habitat needs but preferences seem to vary by river. One partially landlocked population is known in the Holyoke Pool, Connecticut River, and another landlocked group may exist in Lake Marion on the Santee River in South Carolina. Shortnose sturgeon are euryhaline, since they do not spend a large part of their life in estuaries, and migrate between the sea and freshwater habitats.
Range 2
Shortnose sturgeon occur in most major river systems along the eastern seaboard of the United States, from the St. Johns River in Florida to the St. John River in New Brunswick, Canada. Historically, they extended a little further south to the Indian River of Florida
Reproductive / Life span 2
The shortnose sturgeon is an anadromous species. Adults migrate to the upper reaches of a river to spawn. In southern rivers, they spawn in early spring. In the northern rivers, shortnose sturgeon spend less time near the ocean and spawn a bit later in the year. Spawning usually ceases when water temperatures reach 54 to 59°F (12-15°C). Spawning habitat preferences vary by river system (NMFS 1998). Females average 94,000 eggs per year.
Yearlings move downstream after growth and development. In most rivers, juveniles 3 to 10 years old are found in the saltwater/freshwater interface. The adults forage at the interface of fresh tidal water and saline estuaries, with seasonal migrations varying by latitude (NMFS 1998).
Males and females mature at the same length (45 to 55 cm fork length) throughout their range. However, age of first spawning varies from north to south due to a slower growth rate in the north. Males may mature at 2 to 3 years of age in Georgia, at age 3 to 5 from South Carolina to New York, and at age 10 to 11 further north in the St. John River, Canada. Females exhibit a similar trend and approximate age of a female at first spawning is 6 years old or less in the Altahama River, Georgia, 7 to 14 years in the South Carolina rivers, 11 years in the Hudson and Delaware Rivers, and 15 years in the St. John River, Canada. Generally, when female shortnose sturgeon begin spawning, they can spawn every three years thereafter. Productive males may spawn every year
Shortnose sturgeon females have been known to reach 67 years of age! However, males seldom exceed 30
Relatives 2
Shortnose sturgeon are members of the sturgeon family which contains over 30 similar looking species throughout the Northern hemisphere. In the fossil record, the sturgeon group dates back over 200 million years. Sturgeons are famous for their eggs, which are called caviar and cam vary in value (according to species of origin).
Found in the following Estuarine Reserves 2
Wells (ME), Great Bay (NH), Waiquot Bay (MA), Naragansett Bay (RI), Hudson River (NY), Jacques Cousteau (NJ), Delaware, Chesapeake Bay (MD and VA), North Carolina, N. Inlet-Winyah (SC), ACE Basin (SC), and Sapelo Island (GA).
Water quality factors needed for survival 2
•Water Temperature: spawning from 9 to 15 °C, adults tolerate high temperatures
•Turbidity: low to moderate
•Water Flow: < 0.5 m/s
•Salinity: euryhaline - spawn in freshwater streams, adults live in ocean
•Dissolved Oxygen: > 5 mg/L
Threats 2
No estimate of the historical population size of shortnose sturgeon is available, but it has been estimated they suffered a 98% decline (Smith and Clugston 1997). The shortnose sturgeon was rarely the target of a commercial fishery. Yet beginning in colonial times, the commercial fishery not only took Atlantic sturgeon, but incidentally caught shortnose sturgeon. In the 1950s, sturgeon fisheries declined on the east coast, which resulted in a lack of records of shortnose sturgeon. This decline led the U. S. Fish and Wildlife Service (FWS) to conclude that the fish had been eliminated from the rivers in its historic range (except the Hudson River), and was in danger of extinction. FWS believed the shortnose sturgeon’s population size had declined because of pollution and excessive fishing (both directly and incidentally using shad gillnets).
During the period of industrial growth in the late 1800's and early 1900's, dam construction and pollution of many large northeastern river systems may have resulted in substantial loss of suitable habitat. In addition, habitat alterations from discharges, dredging or material disposal into rivers, or related development activities involving estuarine or riverine mudflats, and marshes remain constant threats.
In 1967, the shortnose sturgeon was listed as endangered throughout its range under the Endangered Species Preservation Act of 1966 (a predecessor to the Endangered Species Act of 1973). Under a 1974 government reorganization plan, the National Marine Fisheries Service later assumed jurisdiction for shortnose sturgeon. Placing the species on the endangered species list resulted in a great deal of species research in the northern river systems. In December 1998, NMFS published a Recovery plan outlining necessary actions in order to recover the species.
Conservation notes 2
Importance to Humans and Estuaries
Once, shortnose sturgeon were caught commonly by accident or chance, and used in fisheries throughout their range. This is no longer the case. As large, long-lived predators, and because of their migratory lifestyle, they were a significant source of nutrients being brought into and out of estuaries.
How to Help Protect This Species
Since shortnose sturgeon use estuaries and freshwater areas, they are susceptible to water pollution, plus damage to and alteration of stream channels and riparian zones. Suggested effort to protect this species include:
•Minimize runoff of neighborhood pollutants, fertilizer, and sediment into local streams are helpful to this species or other stream and estuary dwelling species.
•Join a stream or watershed advocacy group in your area to protect your local estuary ecosystems.
•dvocate for the implementation of effective fish passage solutions, so fish can bypass dams and artificial barriers
Advocate restoration of more natural water flow regimes.
Support conservation programs that work to protect the endangered population.
Sources and Credits
- Adapted by GTMResearchReserve from a work by (c) Wikipedia, some rights reserved (CC BY-SA), http://en.wikipedia.org/wiki/Acipenser_brevirostrum
- (c) GTMResearchReserve, some rights reserved (CC BY-SA)
