Shortnose sturgeon have short flattened snouts. They drag whisker like protrusions, called barbells, along the river or ocean bottom to sense food, which they then suck up through toothless tubular mouths. Juveniles feed on insect larvae and crustaceans, whereas the diet of an adult is based on molluscs [Dadswell, 1980]. Shortnose sturgeon are coloured dark brown to black on their dorsal sides with light yellow-brown undersides.
Considered small within the sturgeon family, the shortnose
sturgeon still reaches impressive lengths of around 120 cm, weighing a
maximum of 24 kg [Dadswell et al, 1984]. Female
shortnose sturgeon grow larger than and outlive males.
history and genetics...
The sturgeon family, Acipenseridae, are the only vertebrates in the world where member species can hybridize with one another in the wild. Most vertebrates are diploid, containing 2 copies of their genetic material. Sturgeon are polyploid, containing 4, 8, 12 or 16 copies of their genes. Hybridization to create polyploid sturgeon was one of the main processes creating different sturgeon species. The shortnose sturgeon is 16-ploid, and this high number of genetic copies suggests that it was one of the last sturgeon species to evolve [Birstein et al, 1997].
Fertilization is external, each female releasing 27 000
to 280 000 eggs [Dadswell et al, 1984]. Fertilized
eggs quickly adhere to the hard bottom surfaces and embryos hatch around
5-8 days later, depending on the temperature [Kynard,
Shortnose sturgeon, previously found in all major rivers of the Atlantic coast between Florida and New Brunswick, are now found in only sixteen [Kynard, 1997].
Sturgeon are anadromous, meaning that they live in both freshwater and salt water, depending on the stage of their life cycle. Shortnose sturgeon are amphidromous, spending unequal amounts of time in fresh and salt water [Kieffer & Kynard, 1993]. Northern populations spend more time in salt water or transition zones than southern populations, which dwell primarily in fresh water [Kynard, 1997].
The juveniles of the St. John population in New Brunswick stay in freshwater for several years [Dadswell et al., 1984]. Tolerance of salt water increases with age [Jenkins et al., 1993]. Adults forage for food in the freshwater upper estuaries of the Kennebacasis and Saint John River during the summer [Univ. of New Brunswick]. They migrate downstream to the more saline lower estuary to overwinter and return to the upper estuaries to spawn in the spring [Dadswell, 1979].
The New Brunswick population of shortnose sturgeon was estimated at around 18 000 adults, or close to 100 000 individuals of all age groups, making it one of the largest populations along the Atlantic coast [Dadswell, 1979].
Shortnose sturgeon were listed as
endangered in the United States in 1967, increasing the importance of
conserving a healthy population within Canada.
Today, the largest threat to the Canadian population of shortnose sturgeon is pollution of the waters used by young juveniles, considered the most sensitive life stage.
The bony plates along the shortnose sturgeon's body make them vulnerable to being snagged in gill and trammel nets. The shad gill net industry, where entire rivers are fished with these nets, is a great threat to the species, worsened by the fishery season coinciding with thesturgeon spawning [Collins et al., 1996]. Illegal poaching is also a threat.
Dams have been known to block spawning sturgeon from moving
upstream. Several known populations of shortnose sturgeons have
become landlocked above dams [Collins, 1999]
altering their natural migratory patterns.
Destruction of fish habitat is forbidden under the Federal Fisheries Act of Canada [Federal Fisheries Act, 1985]. Fishing permits are required to catch shortnose sturgeon, and provincial regulations regarding allowable sturgeon size and net sizes are in place.
Attempts at culturing shortnose sturgeon began in the early 1900's [Collins et al, 1999]. These early trials faced the obstacle of not being able to obtain eggs and sperm from the fish simultaneously. Later projects of artificial hatching led to hatching of larvae, but survival rates were low [Buckley & Kynard, 1981]. Breakthroughs in culturing shortnose sturgeon occurred in 1983, using hormones to induce maturation and ovulation [Smith et al., 1985]. The species can now be successfully bred and reared domestically, allowing for continued research without effecting wild populations, and stock enhancement.
Shortnose sturgeon have been successfully stocked into various rivers in the USA, but further study is needed on imprinting of young sturgeon on their river of birth, as some stocked shortnose sturgeon have not taken to their introduced rivers [Smith & Collins, 1996].
Policies to protect the shortnose sturgeon should be specific to the river they inhabit. It is recommended that focus be upon protection and restoration of spawning and summer habitats and reducing fishing mortality by establishing reserves [Collins et al, 2000].
Resources Research Institute, South Carolina Department of Natural Resources
Visit the Sturgeon Conservation site for a great selection of sturgeon links.
A useful sturgeon site can be found at the Sturgeon, Salmon & Steelhead site.
The annual Sturgeon Symposium site contains abstracts about the latest sturgeon research.
Feel like coloring shortnose sturgeon? Try the Endangered Species Coloring Book by Biological Resources, USGS.
Committee on Status of Endangered Wildlife in Canada, COSEWIC, provides listings of Canada's endangered species and more.
Learn more about Canadian fisheries at Fisheries and Oceans Canada (DFO).
Birstein, V.J. and W.E. Bemis. 1997. How many species are there within the genus Acipenser? Environmental Biology of Fishes 48: 157-163.
Browne, Michael. 2000. personal contact through email.
Buckley, J. and B. Kynard. 1981. Spawning and rearing shortnose sturgeon from the Connecticut River. The Progressive Fish Culturist 43 (2): 74-76.
Collins, M.R. and T.I.J. Smith. 1993. Characteristics of the Adult Segment of the Savannah River Population of Shortnose Sturgeon. Proceedings of the Annual Conference of the Southeastern Association of Fish and Wildlife Agencies 47: 485-491.
Collins, M.R., S.G. Rogers, and T.I.J. Smith. 1996. Bycatch of Sturgeons along the Southern Atlantic Coast of the USA. North American Journal of Fisheries Management 16: 24-29.
Collins, M.R., S.G. Rogers, T.I.J. Smith and M.L. Moser. 2000. Primary factors affecting sturgeon populations in the Southeastern United States: Fishing mortality and degradation of essential habitats. Bulletin of Marine Science 66(3): 917-928.
Dadswell, M.J. 1976. Biology of the shortnose sturgeon, Acipenser brevirostrum, in the Saint John River estuary, New Brunswick, Canada. Transactions of the Atlantic Chapter of Canadian Society of Environmental Biology Annual Meeting 1975: 20-72.
Dadswell, M.J. 1979. Biology and population characteristics of the shortnose sturgeon, Acipenser brevirostrum LeSueur, 1818 (Osteichthyes: Acipenseridae), in the Saint John River estuary, New Brunswick, Canada. Canadian Journal of Zoology 57: 2186-2210.
Dadswell, M.J. 1980. Status Report on the Shortnose Sturgeon Acipenser brevirostrum in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa, Ontario. 15 pp.
Dadswell, M.J., B.D. Taubert, T.S. Squiers, D. Marchette and J. Buckley. 1984. Synopsis of Biological Data on Shortnose Sturgeon, Acipenser brevirostrum LeSueur 1818. National Oceanic and Atmospheric Administration Technical Report NMFS 14, National Marine Fisheries Service, Washington, D.C.
Federal Fisheries Act. 1985. Department of Justice of Canada. R.S., c. F-14, s. 1. Federal Government of Canada. [http://canada.justice.gc.ca/FTP/EN/Laws/Chap/F/F-14.txt].
Gorham, S.W. and D.E. McAllister. 1974. The Shortnose Sturgeon, Acipenser brevirostrum, in the Saint John River, New Brunswick, Canada, a rare and possibly endangered species. Syllogeus Series No. 5. The National Museums of Canada. Ottawa. 18 pp.
Jenkins, W.E., T.I.J. Smith, L.D. Heyward, and D.M. Knott. 1993. Tolerance of Shortnose Sturgeon, Acipenser brevirostrum, Juveniles to Different Salinity and Dissolved Oxygen Concentrations. Proceedings of the Annual Conference of Southeastern Association of Fish and Wildlife Agencies 47: 476-484.
Kieffer, M., and B. Kynard. 1993. Annual movements of shortnose and Atlantic sturgeons in the Merrimack River, Massachusetts. Transactions of the American Fisheries Society 122: 1088-1103.
Kynard, B. 1997. Life history, latitudinal patterns, and status of the shortnose sturgeon. Environmental Biology of Fishes 48: 319-334.
Smith, T.I.J., E.K. Dingley, R.D. Lindsey, S.B. Van Sant, R.A. Smiley, and A.D. Stokes. 1985. Spawning and culture of shortnose sturgeon, Acipenser brevirostrum. Journal of the World Mariculture Society 16: 104-113.
Smith, T.I.J., and M.R. Collins. 1996. Shortnose Stocking Success in the Savannah River. Proceedings of the Annual Conference of Southeastern Association of Fish and Wildlife Agencies 50: 112-121.
University of New Brunswick. Publication: Kennebacasis Sturgeon. Dept. of Biology. Saint John, New Brunswick.