The Atlantic sturgeon (''Acipenser oxyrinchus oxyrinchus'') is a member of the family Acipenseridae and along with other sturgeon it is sometimes considered a

living fossil A living fossil is an extant taxon that cosmetically resembles related species known only from the fossil record. To be considered a living fossil, the fossil species must be old relative to the time of origin of the extant clade. Living foss ...

. The Atlantic sturgeon is one of two subspecies of '' A. oxyrinchus'', the other being the Gulf sturgeon (''A. o. desotoi''). The main range of the Atlantic sturgeon is in eastern North America, extending from

New Brunswick New Brunswick (french: Nouveau-Brunswick, , locally ) is one of the thirteen provinces and territories of Canada. It is one of the three Maritime provinces and one of the four Atlantic provinces. It is the only province with both English and ...

, Canada, to the eastern coast of

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

, United States. A disjunct population occurs in the Baltic region of Europe (today only through a reintroduction project). The Atlantic sturgeon was in great abundance when the first European settlers came to North America, but has since declined due to overfishing,

water pollution Water pollution (or aquatic pollution) is the contamination of water bodies, usually as a result of human activities, so that it negatively affects its uses. Water bodies include lakes, rivers, oceans, aquifers, reservoirs and groundwater. ...

, and habitat impediments such as dams. It is considered threatened, endangered, and even locally extinct in many of its original

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

s. The fish can reach 60 years of age, in length and over in weight.

Physical appearance

Rather than having true scales, the Atlantic sturgeon has five rows of bony plates known as

scutes A scute or scutum (Latin: ''scutum''; plural: ''scuta'' " shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of birds. The term is also used to describe the anterio ...

. Specimens weighing over 800 lb and nearly 15 ft in length have been recorded, but they typically grow to be and no more than . Its coloration ranges from bluish-black and olive green on its back to white on its underside. It has a longer snout than other sturgeons and has four

barbel Barbel may refer to: *Barbel (anatomy), a whisker-like organ near the mouth found in some fish (notably catfish, loaches and cyprinids) and turtles *Barbel (fish), a common name for certain species of fish **''Barbus barbus'', a species of cyprinid ...

s at the side of its mouth.

Lifecycle

Atlantic sturgeon under six years of age stay in the

brackish Brackish water, sometimes termed brack water, is water occurring in a natural environment that has more salinity than freshwater, but not as much as seawater. It may result from mixing seawater (salt water) and fresh water together, as in estu ...

water where they were born before moving into the ocean. They may be long at this stage. In areas where

shortnose sturgeon The shortnose sturgeon (''Acipenser brevirostrum'') is a small and endangered species of North American sturgeon. The earliest remains of the species are from the Late Cretaceous Period, over 70 million years ago.National Oceanic and Atmospheri ...

are also present, the adults of that species can be, and historically were for centuries, confused with immature Atlantic sturgeon. When mature, they travel upstream to spawn. The females may lay 800,000 to 3.75 million eggs in a single year, doing so every two to six years. After laying their eggs, females travel back downstream, but males may remain upstream after spawning until forced to return downstream by the increasingly cold water. They may even return to the ocean, where they stay near the

coastline The coast, also known as the coastline or seashore, is defined as the area where land meets the ocean, or as a line that forms the boundary between the land and the coastline. The Earth has around of coastline. Coasts are important zones in ...

. The species is also known for its occasional 'leaping' behavior, during which the fish will emerge completely out of the water in a forceful motion that can be hazardous to anything unlucky enough to be struck. The exact reason why sturgeon leap remains unknown, although some scholars believe leaping is a form of group communication. In one study, of a population of the species in the Suwannee river in northwestern Florida, leaping behavior was found to vary seasonally, with the highest frequency of occurrence in June.

Economic history

Originally, the Atlantic sturgeon was considered a worthless fish. Its rough skin would often rip nets, keeping fishermen from catching more profitable fish. Sturgeon were one of the types of fish harvested at the first North American commercial fishery, and were the first cash "crop" harvested in Jamestown, Virginia. Other fisheries along the Atlantic coast harvested them for use as food, a leather material used in clothing and bookbinding, and

isinglass Isinglass () is a substance obtained from the dried swim bladders of fish. It is a form of collagen used mainly for the clarification or fining of some beer and wine. It can also be cooked into a paste for specialised gluing purposes. The ...

, a gelatinous substance used in clarifying jellies, glues, wines and beer. However, the primary reason for catching sturgeon was the high-quality caviar that could be made cheaply from its eggs, called black gold by watermen. In the late 19th century, seven million pounds of sturgeon meat were exported from the US per year. Within years, however, that amount dropped to 22,000 pounds. The number later rose to about 200,000 pounds a year in the 1950s.

Conservation status

In February 2012, the Atlantic sturgeon was listed by the National Oceanic and Atmospheric Administration Fisheries Service under the Endangered Species Act (ESA). Four

distinct population segment {{no footnotes, date=February 2018 A distinct population segment (DPS) is the smallest division of a taxonomic species permitted to be protected under the U.S. Endangered Species Act. ''Species'', as defined in the Act for listing purposes, is a ...

s (DPSs) were listed as endangered (New York Bight, Chesapeake Bay, Carolina, and South Atlantic) while one DPS was listed as threatened (Gulf of Maine).NMFS. ''Endangered and Threatened Wildlife and Plants; Final Listing Determinations for Two Distinct Population Segments of Atlantic Sturgeon (Acipenser oxyrinchus oxyrinchus) in the Southeast''.''Federal Register;; v77, (February 6, 2012), 5914-5982. As of this writing (July 22, 2015) there are concerns that the construction of the bridge to replace the Tappan Zee connecting Rockland County to Westchester County in New York, in the Hudson River, may impact the sturgeon's

ecological stability In ecology, an ecosystem is said to possess ecological stability (or equilibrium) if it is capable of returning to its equilibrium state after a perturbation (a capacity known as resilience) or does not experience unexpected large changes in its c ...

."Group Petitions to Save a Prehistoric Fish From Modern Construction"
article by Lisa W. Foderaro in ''The New York Times'' July 21, 2015 The American Fisheries Society considers the fish as threatened throughout its entire range, although it is believed to no longer inhabit the full range it once did. In the Chesapeake watershed, the James River in Virginia is one of the last confirmed holdouts for that region's population. In May 2007, a survey captured 175 sturgeon in the river, with 15 specimens exceeding . A bounty-based survey of live Atlantic sturgeon in Maryland's portion of the bay found a high number of captures reported in 2005–06. In 2016, the

National Marine Fisheries Service The National Marine Fisheries Service (NMFS), informally known as NOAA Fisheries, is a United States federal agency within the U.S. Department of Commerce's National Oceanic and Atmospheric Administration (NOAA) that is responsible for the ste ...

considered designating sixteen rivers as endangered habitat, which would require more attention to be given to uses of the rivers that affect the fish. Then in 2018, NMFS actually mapped a total of thirty-one critical river habitats along the United States' Atlantic shores.

Baltic population

The now nearly extinct sturgeon population in the

Baltic Sea The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden and the North and Central European Plain. The sea stretches from 53°N to 66°N latitude and ...

area belongs to the Atlantic sturgeon ''A. oxyrinchus'' rather than to the European species '' A. sturio'' as had been thought. ''A. oxyrinchus'' migrated to the Baltic about 1300 years ago and displaced the native ''A. sturio''. The last known specimen of the Atlantic sturgeon in the Baltic region was caught in 1996 near

Muhumaa Muhu (also called Muhumaa in Estonian), is an island in the West Estonian archipelago of the Baltic Sea. With an area of it is the third largest island belonging to Estonia, after Saaremaa and Hiiumaa. Together with neighbouring smaller isla ...

Estonia Estonia, formally the Republic of Estonia, is a country by the Baltic Sea in Northern Europe. It is bordered to the north by the Gulf of Finland across from Finland, to the west by the sea across from Sweden, to the south by Latvia, a ...

. It was long, weighed , and was estimated to be about 50 years old. A German-Polish project was underway in 2009 to reintroduce the sturgeon into the Baltic by releasing specimens caught in the Canadian Saint John River into the Oder, a river at the border between Germany and Poland where the species once spawned. The project expanded in 2013 to include Estonia, where one-year-old juveniles were released into the

Narva River The river Narva ( et, Narva jõgi; russian: Нарва), formerly also Narova flows north into the Baltic Sea and is the largest Estonian river by discharge. A similar length of land far to the south, together with it and a much longer interme ...

Conservation designation

IUCN:

Near Threatened A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify f ...

CITES: Appendix II The American Fisheries Society considers it endangered in all stream systems except conservation-dependent in the Hudson, Delaware, and Altamaha Rivers. The Atlantic sturgeon of the Delaware River are listed under the ESA as part of the New York Bight

, which includes all Atlantic sturgeon that spawn in watersheds draining to coastal waters from Chatham, Massachusetts, to the Delaware-Maryland border on Fenwick Island. NMFS believes fewer than 300 spawning adults are in the Delaware River population; just over 100 years ago the estimated population was 180,000 spawning adult females.

Management

Atlantic sturgeon are now a threatened species. Management of the species is largely based on the restriction of fishing of the species. This helps limit fishing mortalities of sturgeon to bycatch.