About The Species
Atlantic sturgeon live in rivers and coastal waters from Canada to Florida. Hatched in the freshwater of rivers, Atlantic sturgeon head out to sea as juveniles, and return to their birthplace to spawn, or lay eggs, when they reach adulthood.
The Atlantic sturgeon has five rows of bony plates known as scutes that run along its body and a snout with four slender, soft tissue projections, called barbels, in front of its mouth. In addition, the tail is like a shark’s where one side, or lobe, is larger than the other. All of these features give the fish its unique look.
Atlantic sturgeon are slow-growing and late-maturing, and have been recorded to reach up to 14 feet in length and up to 60 years of age.
Atlantic sturgeon were once found in great abundance, but their populations have declined greatly due to overfishing and habitat loss. Atlantic sturgeon were prized for their eggs, which were valued as high-quality caviar. During the late 1800s, people flocked to the Eastern United States in search of caviar riches from the sturgeon fishery, known as the “Black Gold Rush.” By the beginning of the 1900s, sturgeon populations had declined drastically. Close to 7 million pounds of sturgeon were reportedly caught in 1887, but by 1905 the catch declined to only 20,000 pounds, and by 1989 only 400 pounds of sturgeon were recorded.
Today, all five U.S. Atlantic sturgeon distinct population segments are listed as endangered or threatened under the Endangered Species Act. The populations in Canada are not protected. The primary threats currently facing Atlantic sturgeon are entanglement in fishing gear, habitat degradation, habitat impediments such as dams and other barriers and vessel strikes.
NOAA Fisheries and our partners are dedicated to conserving and rebuilding Atlantic sturgeon populations along the East Coast. We use a variety of innovative techniques to study, protect, and recover these endangered fish. Working closely with our partners, we develop regulations and management plans that preserve and restore sturgeon habitat, monitor bycatch, and promote population recovery.
The historical and current range of Atlantic sturgeon includes major estuaries and river systems from Canada to Florida. While still found throughout their historical range, Atlantic sturgeon spawning is known to occur in only 22 of 38 historical spawning rivers.
Atlantic sturgeon were listed under the ESA in 2012 as five distinct population segments. A distinct population segment is the smallest division of a species permitted to be protected under the ESA. Atlantic sturgeon that hatch out in Gulf of Maine rivers are listed as threatened, and those that hatch out in other U.S. rivers are listed as endangered. Atlantic sturgeon are not protected in Canada.
- Carolina DPS
- Chesapeake Bay DPS
- New York Bight DPS
- South Atlantic DPS
- Gulf of Maine DPS
Atlantic sturgeon can grow to approximately 16 feet long and can weigh up to 800 pounds. 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,” or thorny plates along the length of their body.
Atlantic sturgeon are similar in appearance to shortnose sturgeon, but can be distinguished by their larger size, smaller mouth, different snout shape, and tail scute pattern.
Behavior and Diet
Adult spawning runs of Atlantic sturgeon are still not completely understood. In rivers from Georgia to the Chesapeake Bay, scientists have confirmed that adult sturgeon spawn during the late summer and fall. In rivers from Delaware to Canada, adults spawn in the spring and early summer. Some researchers have hypothesized that spawning may occur in both the spring and fall, particularly likely in the mid-Atlantic, but that is yet to be confirmed in any river. Because adult Atlantic sturgeon migrate along the coast when not spawning and tend to preferentially use estuaries, estuarine-oriented adults may appear to be preparing to spawn in the spring or fall, but are actually just feeding. Juvenile fish can leave their natal rivers as early as one year of age, so sometimes juvenile aggregations within a river may be composed of two or more different natal populations of fish.
After spawning in northern rivers, males may remain in the river or lower estuary until the fall; females typically exit the rivers within four to six weeks after spawning. In southern rivers, males usually enter the river in late summer when temperatures can be as high as 90°F, spawn as river temperatures approach 75 to 70°F, with females leaving immediately after spawning and males leaving as temperatures drop below 65°F. Upon hatching, larvae hide along the bottom and drift downstream until they reach brackish waters where they may reside for one to five years before moving into nearshore coastal waters. Tagging data indicate that these immature Atlantic sturgeon travel widely once they leave their birth rivers.
Atlantic sturgeon are bottom feeders. They typically look for food that includes invertebrates such as crustaceans, worms, and mollusks, and bottom-dwelling fish such as sand lance.
Where They Live
Historically, Atlantic sturgeon ranged along the Canadian and U.S. Atlantic Coast from Labrador to Florida. Due to overfishing, the abundance of natal populations is much less than historic levels, but breeding populations still exist in at least 22 U.S. rivers from Maine to Georgia and in several more in Canada. Atlantic sturgeon are anadromous fish—they are born in freshwater, then migrate to the sea and back again to freshwater to spawn. Most juveniles remain in their river of birth (natal river) for at least several months before migrating out to the ocean. Tagging data indicate that these immature Atlantic sturgeon travel widely up and down the East Coast, and as far as Iceland, when they are at sea.
Lifespan & Reproduction
Atlantic sturgeon lifespan is correlated with how far north or south they live. They live up to 60 years in Canada, but likely only 25 to 30 years in the southeast. Southern populations typically grow faster and reach sexual maturity earlier than northern 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.
Atlantic sturgeon spawning intervals range from 1 to 5 years for males and 2 to 5 years for females, with males returning almost every year and females usually returning every other year or every third year. Female egg production correlates with age and body size, and ranges from 400,000 to 1.6 million eggs. In the Hudson River, females reach 50 percent of their maximum lifetime egg production at approximately 29 years. Fish from more southern rivers reach this production earlier and fish from Maine and Canada later. Atlantic sturgeon take approximately 3 to 10 times longer than other bony fish species to reach 50 percent of maximum lifetime egg production.
The most significant threats to Atlantic sturgeon are unintended catch in some commercial fisheries, dams that block access to spawning areas, poor water quality (which harms development of sturgeon offspring), dredging of spawning areas, water withdrawals from rivers, and vessel strikes.
Fisheries Interactions and Bycatch
Atlantic sturgeon are sometimes accidentally caught by fishermen trying to catch something else. This is called bycatch.
Bycatch occurs primarily in gillnet and trawl fisheries. The prevalence and likelihood of bycatch varies by fishing season. The fishing season also impacts the likelihood of sturgeon survival, which is more likely in cooler waters. Adults can be captured when moving into rivers to spawn. Juveniles can be captured in rivers and estuaries when moving from their nursery habitat or year-round while swimming and feeding. Fisheries conducted within rivers and estuaries may intercept any life stage, while fisheries conducted in the nearshore and ocean waters are more likely to capture migrating juveniles and adults.
Atlantic sturgeon habitat can be disrupted or lost because of various human activities, such as dredging, dams, water withdrawals, saltwater intrusion (often caused by groundwater pumping from freshwater wells or drought), chemical contamination of sediments in rearing areas, and other development. Sturgeon need hard bottom substrates in freshwater reaches for spawning, so any activity that destroys those locations directly (e.g., dredging) or indirectly (e.g., sedimentation or saltwater intrusion) would affect Atlantic sturgeon habitat. To support all life stages, Atlantic sturgeon also require sufficient water quantities and water qualities sufficient to support all life stages, which are often impacted by the activities above.
Locks and dams on the Cape Fear River, North Carolina; the Santee-Cooper rivers, South Carolina; Savannah River, South Carolina/Georgia and the Connecticut River, Connecticut, impede access to upstream spawning habitat. Recent dam removal projects on the Penobscot River, Maine and Rappahannock River, Virginia, have increased accessibility to upstream habitats.
Atlantic sturgeon can be struck by the blades of a propeller as a boat is passing, or struck by the boat itself. The risk of injury and mortality can be high in areas with high ship traffic, including the Hudson, Delaware, and James rivers. They are struck and killed by large commercial vessels as well as smaller vessels such as recreational vessels. We do not know how many sturgeon are struck by vessels and survive their injuries.
Atlantic Sturgeon are protected under the Endangered Species Act. In 2012, four distinct population segments were listed as endangered (New York Bight, Chesapeake Bay, Carolina, and South Atlantic DPSs) and one DPS was listed as threatened (Gulf of Maine DPS).
This means that the Atlantic sturgeon is in danger of extinction throughout all or a significant portion of its range. NOAA Fisheries is working to protect this species with the goal of population recovery.
Recovery Planning and Implementation
NOAA Fisheries developed a recovery outline to commence the recovery planning process for Atlantic sturgeon. The outline is meant to serve as an interim guidance document to direct recovery efforts, including recovery planning, for the endangered New York Bight, Chesapeake Bay, Carolina, and South Atlantic DPSs of the Atlantic sturgeon and the threatened Gulf of Maine DPS until a full recovery plan is developed and approved.
Critical Habitat Designation
Once a species is listed under the ESA, NOAA Fisheries evaluates and identifies whether any areas meet the definition of critical habitat. Those areas may be designated as critical habitat through a rulemaking process. The designation of an area as critical habitat does not create a closed area, marine protected area, refuge, wilderness reserve, preservation, or other conservation area; nor does the designation affect land ownership. Federal agencies that undertake, fund, or permit activities that may affect these designated critical habitat areas are required to consult with NOAA Fisheries to ensure that their actions do not adversely modify or destroy designated critical habitat.
On August 17, 2017, we designated areas in each of the distinct population segments of Atlantic sturgeon as critical habitat. We designated these areas because they protect spawning locations, rearing areas, water quality, and water quantity necessary for Atlantic sturgeon survival.
- Maps of Designated Critical Habitat Rivers for the Gulf of Maine, New York Bight, and Chesapeake Bay DPSs
- Maps of Designated Critical Habitat Rivers for the Carolina and South Atlantic DPSs
Restoring Habitats and Fish Passages
Sturgeon and other migrating fish, such as salmon, shad, and alewives, need access to freshwater habitat for spawning and rearing. In some cases, Atlantic sturgeon need to swim thousands of miles through the oceans and rivers to reach their destination, but they may be blocked from completing their journey by man-made barriers, such as dams. These barriers have had serious impacts on Atlantic sturgeon spawning runs along the entire East Coast, particularly in the Southeast. Removal of outdated dams can greatly improve Atlantic sturgeon access to historical habitats. NOAA Fisheries works with conservation organizations, energy companies, states, tribes and citizens to evaluate barriers and improve fish passage. Most barriers have the same general impact on fish—blocking migrations—but each requires a specific set of conservation actions. Learn more about improving fish passage.
The Penobscot River—New England’s second largest river—has been designated a NOAA Habitat Focus Area, as human activities have caused adverse impacts to the watershed. Recovery of endangered and threatened Atlantic sturgeon, shortnose sturgeon, and Atlantic salmon are a key objective of the ongoing habitat improvement efforts.
Educating the Public
We believe that one of the best ways to help save this amazing species is by getting the word out through outreach. Our scientists are working with students and teachers to learn more about the movements, behavior, and threats to Atlantic and shortnose sturgeons along the East Coast. The Students Collaborating to Undertake Tracking Efforts for Sturgeon (SCUTES) program provides lesson plans, educational kits, and an opportunity for classrooms to adopt a tagged sturgeon.
The Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES) protects Atlantic sturgeon and other sturgeons by regulating international trade in listed species of plants and animals.
Key Actions and Documents
NOAA Fisheries conducts various research activities on the biology, behavior, and ecology of the Atlantic sturgeon. This research informs management decisions and enhances recovery efforts for endangered and threatened Atlantic sturgeon populations.
Tagging and Tracking
Scientists are using tagging techniques to learn about the migration patterns of Atlantic sturgeon and identify important juvenile habitats. Dart, passive integrated transponder (PIT), radio, satellite, pop off, and acoustic tags are being used. Tags such as PIT tags and dart tags allow for an individual fish to be identified by other researchers when it is captured. Acoustic and satellite telemetry tags let researchers learn where Atlantic sturgeon migrate, at what depths, and at what speeds.
Atlantic sturgeon researchers take small fin clips from every sturgeon they catch to better understand the genetic composition of all populations. Atlantic sturgeon that are accidentally captured or killed in non-research-related projects can be matched to the river where they were born using information in their DNA (“genotype”). In other cases, a tissue sample from sturgeon spawning (releasing or depositing eggs) in a particular river can be taken. After the sample is processed by a lab, the genetic information in that sample can be stored with other Atlantic sturgeon genotypes to create baselines of the unique genotypes found for each spawning population. Those baselines allow sturgeon to be identified back to their natal river. Genetic variation (“heterogeneity”) within the population can also be used to estimate the minimum number of spawning adults that would have been required to generate that level of heterogeneity, which helps us learn more about the approximate number of successfully spawning adults, their natal river, and their family history. NOAA Fisheries is creating a searchable database to allow researchers to know which samples are available to be analyzed and which have already been analyzed.
NOAA Fisheries, in partnership with numerous federal and academic researchers, monitors effective population size of the spawning populations that have been adequately sampled to produce estimates. While effective population sizes are not easily translated to actual abundance estimates, they can provide a rough comparison between populations to better understand relative abundance and threats of inbreeding or extirpation. The most recent population estimates are, from north to south:
St. Lawrence River - between 28 and 99 individuals.
St. John River - between 85 and 577 individuals.
Kennebec River - between 63 and 110 individuals.
Connecticut River - between 2 and 3 individuals.
Hudson River - between 172 and 230 individuals.
Delaware River - between 75 and 186 individuals.
James River - between 40 and 100 individuals.
York River - between 6 and 12 individuals.
Albemarle Sound (likely Roanoke River population) - between 16 and 22 individuals.
Edisto River - between 30 and 51 individuals.
Savannah River - between 50 and 99 individuals.
Ogeechee River - between 33 and 78 individuals.
Altamaha River - between 76 and 189 individuals.
Side Scan Sonar
Recently, side scan sonar has been used to approximate the number of sturgeon that appear on the image. Abundance is estimated by calculating the probability of occupation along each transect to produce estimates within the whole river. However, this approach is still being perfected. Most rivers are wide enough that multiple 50m wide transects are needed and long enough that sampling the entire river isn’t possible. Therefore, an equation to account for unsampled areas and fish counted multiple times is needed to correct the estimate.
To reduce bycatch, we have funded research that is creating promising new fishing gear configurations that maintain catch rates of target species but protect Atlantic sturgeon. For gill nets, using a raised footrope has shown promise for some fisheries. For trawls, the turtle excluder devices are also effective at keeping Atlantic sturgeon out.
The likelihood of mortality of incidentally gill-netted Atlantic sturgeon appears to be related to water quality, how the net is set, and the length of time it is left before being tended. Overall, anchored gill nets (i.e., set on the bottom, as opposed to floating at the surface) tend to cause the greatest risk for mortality of Atlantic sturgeon, compared to other gill nets or types of gear. Atlantic sturgeon incidentally captured in cooler waters have a greater likelihood of survival than those captured in warmer waters. However, the likelihood of survival also appears to increase when bycatch reduction devices are used.
In 2013, the Atlantic States Marine Fisheries Commission initiated a coastwide benchmark population assessment for Atlantic sturgeon to evaluate stock status, stock delineation, and bycatch. The assessment was completed in October 2017 and determined Atlantic sturgeon populations are depleted but stable.
This document presents a preliminary outline for the recovery of all five distinct population…
This document provides a summary of the information gathered for an Endangered Species Act (ESA)…
Data & Maps
Tracks the implementation of recovery actions from Endangered Species Act (ESA) recovery plans.