Atlantic stingray
Encyclopedia
The Atlantic stingray is a species
of stingray
in the family
Dasyatidae, common along the Atlantic coast of North America
from Chesapeake Bay
to Mexico
, including brackish and freshwater
habitat
s. It may be distinguished from other stingrays in the area by its relatively elongated snout. This species is of no commercial importance.
Charles Alexandre Lesueur
as Trygon sabina, in an 1824 volume of the Journal of the Academy of Natural Sciences of Philadelphia. He based his account on a damaged male specimen collected by American naturalist Titian Ramsay Peale during the Academy
's 1817 expedition to Florida
. Since then, various authors have included this species in the obsolete genera Pastinaca, Dasybatus (or the variants Dasibatis and Dasybatis), and Amphotistius, all of which were eventually synonymized
with the genus Dasyatis.
A 2001 phylogenetic analysis by Lisa Rosenberger, based on morphology
, found that the Atlantic stingray is one of the more basal members of its genus
. It is the outgroup to a large clade
that contains, amongst others, the southern stingray
(D. americana), the roughtail stingray
(D. centroura), the longnose stingray
(D. guttata), and the pearl stingray
(D. margaritella).
The Atlantic stingray is found in the western Atlantic Ocean
from Chesapeake Bay
southward to Florida
and the Gulf of Mexico
, to as far as Campeche
, Mexico
. Records of this species from Grenada
, Suriname
, and Brazil
are doubtful and may represent other species. The Atlantic stingray is capable of tolerating varying salinities
and can enter freshwater
; it has been reported from the Mississippi River
, Lake Pontchartrain
, and the St. Johns River
in Florida
. The stingrays in the St. Johns River system represent the only permanent freshwater elasmobranch population in North America.
This species inhabits shallow coastal waters over sandy or silty bottoms, estuaries
, and lake
s. They prefer water temperatures over 15 °C (59 °F) and can tolerate temperatures over 30 °C (86 °F). These stingrays conduct seasonal migrations to stay in warmer water: they are only present in the northerly Chesapeake bay in the summer and fall, and elsewhere they migrate to deeper water in the winter. When inshore, they usually stay at depths of 2–6 m (6.6–19.7 ft), and after migrating offshore they may be found as deep as 25 m (82 ft).
is relatively long. There are three stout papilla
e on the floor of the mouth; the teeth are rounded, with a flat, blunt surface. During the reproductive season, the teeth of mature males change to feature long, sharp cusps that curve towards the corners of the mouth, for gripping onto females during mating. The tail
is long and whip-like, with a serrated spine measuring a quarter of the width of the disk. The spine is replaced annually between June and October. Dorsal and ventral fin folds are present on the tail.
Larger Atlantic stingrays develop tubercles or thorns along the midline of the back to the origin of the tail spine. Some larger females also develop tubercles around the eyes and spiracle
s. The coloration is brown or yellowish brown above, becoming lighter towards the margin of the disk and sometimes with a dark stripe along the midline, and white or light gray below. The tail fin folds are yellowish. In larger individuals the tail may be flecked with gray near the base and completely dark towards the tip.
The Atlantic stingray feeds mostly on benthic invertebrate
s such as bivalves, tube anemones, amphipods, crustacean
s, and nereid worms, which they locate using their electroreceptive ampullae of Lorenzini
. The exact composition of their diet varies by geographical location. When feeding, these rays will position themselves facing the current so that the sediment will be washed away. Numerous species of shark
s, such as the tiger shark
(Galeocerdo cuvier) and the bull shark
(Carcharhinas leucas), are major predators of the Atlantic stingray. In freshwater habitats, they may be preyed upon by American alligator
s (Alligator mississippiensis). A known parasite of freshwater Atlantic stingrays is Argulus, a fish louse that feeds on skin mucus
.
Despite having a regular freshwater presence, the Atlantic stingray is physiologically euryhaline
and no population has evolved the specialized osmoregulatory
mechanisms found in the river stingrays of the family Potamotrygonidae
. This may be due to the relatively recent date of freshwater colonization (under one million years), and/or possibly incomplete genetic isolation of the freshwater populations, as they remain capable of surviving in salt water
. Freshwater Atlantic stingrays have only 30-50% the concentration of urea
and other osmolyte
s in their blood compared to marine populations. However, the osmotic pressure
between their internal fluids and external environment still causes water to diffuse
into their bodies, and they must produce large quantities of dilute urine
(at 10 times the rate of marine individuals) to compensate.
Like other stingrays, the Atlantic stingray is ovoviviparous. Both marine and freshwater populations in Florida
have an annual mating season from September or October to April, though ovulation
does not occur until late March or early April. Courtship involves the male following the female and biting at her body and fins, and the male will grip onto the female's pectoral fin to assist in copulation. The embryo
s are sustained by a yolk sac
until around day 60, after which they are nourished by uterine milk secreted by the mother. Litters of 1-4 young are born from late July to early August, after a gestation period
of 4-4.5 months. Newborns measure 10–13 cm (3.9–5.1 in) wide. Marine males mature at a disk width of 20 cm (7.9 in) and females at a disk width of 24 cm (9.4 in). Freshwater males mature at a disk width of 21 cm (8.3 in) and females at a disk width of 22 cm (8.7 in).
in gillnet
s targeting flounder
off North Carolina
, but most are released alive. They are also caught as bycatch in small numbers in recreational and commercial trout
gillnets, shark
drift net
s, and nearshore trawls. As there is no fishery
targeting this species and bycatch mortality appears to be low, it was assessed as of Least Concern
by the World Conservation Union
. However, some localized freshwater populations have shown reduced health and reproduction due to declining water quality.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of stingray
Myliobatiformes
Myliobatiformes is one of the four orders of batoids, cartilaginous fishes related to sharks. They were formerly included in the order Rajiformes, but more recent phylogenetic studies have shown that the myliobatiforms are a monophyletic group, and that its more derived members evolved their...
in the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Dasyatidae, common along the Atlantic coast of North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
from Chesapeake Bay
Chesapeake Bay
The Chesapeake Bay is the largest estuary in the United States. It lies off the Atlantic Ocean, surrounded by Maryland and Virginia. The Chesapeake Bay's drainage basin covers in the District of Columbia and parts of six states: New York, Pennsylvania, Delaware, Maryland, Virginia, and West...
to Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
, including brackish and freshwater
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...
habitat
Habitat
* Habitat , a place where a species lives and grows*Human habitat, a place where humans live, work or play** Space habitat, a space station intended as a permanent settlement...
s. It may be distinguished from other stingrays in the area by its relatively elongated snout. This species is of no commercial importance.
Taxonomy and phylogeny
The Atlantic stingray was described by French naturalistNaturalist
Naturalist may refer to:* Practitioner of natural history* Conservationist* Advocate of naturalism * Naturalist , autobiography-See also:* The American Naturalist, periodical* Naturalism...
Charles Alexandre Lesueur
Charles Alexandre Lesueur
Charles Alexandre Lesueur was a French naturalist, artist and explorer.Pictured here is the oil portrait by Charles Willson Peale of Charles-Alexandre Lesueur...
as Trygon sabina, in an 1824 volume of the Journal of the Academy of Natural Sciences of Philadelphia. He based his account on a damaged male specimen collected by American naturalist Titian Ramsay Peale during the Academy
Academy of Natural Sciences
The Academy of Natural Sciences of Drexel University, formerly Academy of Natural Sciences of Philadelphia, is the oldest natural science research institution and museum in the New World...
's 1817 expedition to Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
. Since then, various authors have included this species in the obsolete genera Pastinaca, Dasybatus (or the variants Dasibatis and Dasybatis), and Amphotistius, all of which were eventually synonymized
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...
with the genus Dasyatis.
A 2001 phylogenetic analysis by Lisa Rosenberger, based on morphology
Morphology (biology)
In biology, morphology is a branch of bioscience dealing with the study of the form and structure of organisms and their specific structural features....
, found that the Atlantic stingray is one of the more basal members of its genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
. It is the outgroup to a large clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
that contains, amongst others, the southern stingray
Southern stingray
The southern stingray, Dasyatis americana, is a stingray of the family Dasyatidae found in tropical and subtropical waters of the Western Atlantic Ocean from New Jersey to Brazil. It has a flat, diamond-shaped disc, with a mud brown, olive, and grey dorsal surface and white underbelly...
(D. americana), the roughtail stingray
Roughtail stingray
The roughtail stingray is a species of stingray in the family Dasyatidae, with separate populations in coastal waters of the northwestern, eastern, and southwestern Atlantic Ocean. This bottom-dwelling species typically inhabits sandy or muddy areas with patches of invertebrate cover, at a depth of...
(D. centroura), the longnose stingray
Longnose stingray
The longnose stingray, Dasyatis guttata, is a species of stingray in the family Dasyatidae, native to the western Atlantic Ocean from the southern Gulf of Mexico to Brazil. Found in coastal waters no deeper than , this demersal species favors muddy or sandy habitats...
(D. guttata), and the pearl stingray
Pearl stingray
The pearl stingray is a little-known species of stingray in the family Dasyatidae, found in shallow coastal waters from Mauritania to Angola. Growing to across, this species has a rounded pectoral fin disc with a pointed snout, and a wide band of dermal denticles over the back in adults...
(D. margaritella).
Distribution and habitat
Atlantic Ocean
The Atlantic Ocean is the second-largest of the world's oceanic divisions. With a total area of about , it covers approximately 20% of the Earth's surface and about 26% of its water surface area...
from Chesapeake Bay
Chesapeake Bay
The Chesapeake Bay is the largest estuary in the United States. It lies off the Atlantic Ocean, surrounded by Maryland and Virginia. The Chesapeake Bay's drainage basin covers in the District of Columbia and parts of six states: New York, Pennsylvania, Delaware, Maryland, Virginia, and West...
southward to Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
and the Gulf of Mexico
Gulf of Mexico
The Gulf of Mexico is a partially landlocked ocean basin largely surrounded by the North American continent and the island of Cuba. It is bounded on the northeast, north and northwest by the Gulf Coast of the United States, on the southwest and south by Mexico, and on the southeast by Cuba. In...
, to as far as Campeche
Campeche
Campeche is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. Located in Southeast Mexico, it is bordered by the states of Yucatán to the north east, Quintana Roo to the east, and Tabasco to the south west...
, Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
. Records of this species from Grenada
Grenada
Grenada is an island country and Commonwealth Realm consisting of the island of Grenada and six smaller islands at the southern end of the Grenadines in the southeastern Caribbean Sea...
, Suriname
Suriname
Suriname , officially the Republic of Suriname , is a country in northern South America. It borders French Guiana to the east, Guyana to the west, Brazil to the south, and on the north by the Atlantic Ocean. Suriname was a former colony of the British and of the Dutch, and was previously known as...
, and Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
are doubtful and may represent other species. The Atlantic stingray is capable of tolerating varying salinities
Salinity
Salinity is the saltiness or dissolved salt content of a body of water. It is a general term used to describe the levels of different salts such as sodium chloride, magnesium and calcium sulfates, and bicarbonates...
and can enter freshwater
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...
; it has been reported from the Mississippi River
Mississippi River
The Mississippi River is the largest river system in North America. Flowing entirely in the United States, this river rises in western Minnesota and meanders slowly southwards for to the Mississippi River Delta at the Gulf of Mexico. With its many tributaries, the Mississippi's watershed drains...
, Lake Pontchartrain
Lake Pontchartrain
Lake Pontchartrain is a brackish estuary located in southeastern Louisiana. It is the second-largest inland saltwater body of water in the United States, after the Great Salt Lake in Utah, and the largest lake in Louisiana. As an estuary, Pontchartrain is not a true lake.It covers an area of with...
, and the St. Johns River
St. Johns River
The St. Johns River is the longest river in the U.S. state of Florida and its most significant for commercial and recreational use. At long, it winds through or borders twelve counties, three of which are the state's largest. The drop in elevation from the headwaters to the mouth is less than ;...
in Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
. The stingrays in the St. Johns River system represent the only permanent freshwater elasmobranch population in North America.
This species inhabits shallow coastal waters over sandy or silty bottoms, estuaries
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....
, and lake
Lake
A lake is a body of relatively still fresh or salt water of considerable size, localized in a basin, that is surrounded by land. Lakes are inland and not part of the ocean and therefore are distinct from lagoons, and are larger and deeper than ponds. Lakes can be contrasted with rivers or streams,...
s. They prefer water temperatures over 15 °C (59 °F) and can tolerate temperatures over 30 °C (86 °F). These stingrays conduct seasonal migrations to stay in warmer water: they are only present in the northerly Chesapeake bay in the summer and fall, and elsewhere they migrate to deeper water in the winter. When inshore, they usually stay at depths of 2–6 m (6.6–19.7 ft), and after migrating offshore they may be found as deep as 25 m (82 ft).
Description
One of the smallest stingray species, the Atlantic stingray attains a maximum length of 61 cm (24 in) and a weight of 4.9 kg (10.8 lb). It has a spade-shaped pectoral fin disk 1.1 times as wide as long, with rounded corners and concave anterior margins. The snoutSnout
The snout, or muzzle, is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw.-Terminology:The term "muzzle", used as a noun, can be ambiguous...
is relatively long. There are three stout papilla
Papilla (fish mouth structure)
The papilla, in certain kinds of fish, particularly rays, sharks, and catfish, are small lumps of dermal tissue found in the mouth, where they are "distributed uniformly on the tongue, palate, and pharynx"...
e on the floor of the mouth; the teeth are rounded, with a flat, blunt surface. During the reproductive season, the teeth of mature males change to feature long, sharp cusps that curve towards the corners of the mouth, for gripping onto females during mating. The tail
Tail
The tail is the section at the rear end of an animal's body; in general, the term refers to a distinct, flexible appendage to the torso. It is the part of the body that corresponds roughly to the sacrum and coccyx in mammals, reptiles, and birds...
is long and whip-like, with a serrated spine measuring a quarter of the width of the disk. The spine is replaced annually between June and October. Dorsal and ventral fin folds are present on the tail.
Larger Atlantic stingrays develop tubercles or thorns along the midline of the back to the origin of the tail spine. Some larger females also develop tubercles around the eyes and spiracle
Spiracle
Spiracles are openings on the surface of some animals that usually lead to respiratory systems.-Vertebrates:The spiracle is a small hole behind each eye that opens to the mouth in some fishes. In the primitive jawless fish the first gill opening immediately behind the mouth is essentially similar...
s. The coloration is brown or yellowish brown above, becoming lighter towards the margin of the disk and sometimes with a dark stripe along the midline, and white or light gray below. The tail fin folds are yellowish. In larger individuals the tail may be flecked with gray near the base and completely dark towards the tip.
Biology and ecology
Invertebrate
An invertebrate is an animal without a backbone. The group includes 97% of all animal species – all animals except those in the chordate subphylum Vertebrata .Invertebrates form a paraphyletic group...
s such as bivalves, tube anemones, amphipods, crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...
s, and nereid worms, which they locate using their electroreceptive ampullae of Lorenzini
Ampullae of Lorenzini
The ampullae of Lorenzini are special sensing organs called electroreceptors, forming a network of jelly-filled pores. They are mostly discussed as being found in cartilaginous fishes ; however, they are also reported to be found in Chondrostei such as Reedfish and sturgeon. Lungfish have also been...
. The exact composition of their diet varies by geographical location. When feeding, these rays will position themselves facing the current so that the sediment will be washed away. Numerous species of shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s, such as the tiger shark
Tiger shark
The tiger sharks, Galeocerdo cuvier, is a species of requiem shark and the only member of the genus Galeocerdo. Commonly known as sea tigers, tiger sharks are relatively large macropredators, capable of attaining a length of over . It is found in many tropical and temperate waters, and is...
(Galeocerdo cuvier) and the bull shark
Bull shark
The bull shark, Carcharhinus leucas, also known as Zambezi shark or unofficially known as Zambi in Africa and Nicaragua shark in Nicaragua, is a shark common worldwide in warm, shallow waters along coasts and in rivers...
(Carcharhinas leucas), are major predators of the Atlantic stingray. In freshwater habitats, they may be preyed upon by American alligator
American Alligator
The American alligator , sometimes referred to colloquially as a gator, is a reptile endemic only to the Southeastern United States. It is one of the two living species of alligator, in the genus Alligator, within the family Alligatoridae...
s (Alligator mississippiensis). A known parasite of freshwater Atlantic stingrays is Argulus, a fish louse that feeds on skin mucus
Mucus
In vertebrates, mucus is a slippery secretion produced by, and covering, mucous membranes. Mucous fluid is typically produced from mucous cells found in mucous glands. Mucous cells secrete products that are rich in glycoproteins and water. Mucous fluid may also originate from mixed glands, which...
.
Despite having a regular freshwater presence, the Atlantic stingray is physiologically euryhaline
Euryhaline
Euryhaline organisms are able to adapt to a wide range of salinities. An example of a euryhaline fish is the molly which can live in fresh, brackish, or salt water. The European shore crab is an example of a euryhaline invertebrate that can live in salt and brackish water...
and no population has evolved the specialized osmoregulatory
Osmoregulation
Osmoregulation is the active regulation of the osmotic pressure of an organism's fluids to maintain the homeostasis of the organism's water content; that is it keeps the organism's fluids from becoming too diluted or too concentrated. Osmotic pressure is a measure of the tendency of water to move...
mechanisms found in the river stingrays of the family Potamotrygonidae
Potamotrygonidae
River stingrays are Neotropical freshwater fishes of the Potamotrygonidae family .They are native to northern, central and eastern South America, living in rivers that drain into the Caribbean, and into the Atlantic as far south as the Río de la Plata in Argentina...
. This may be due to the relatively recent date of freshwater colonization (under one million years), and/or possibly incomplete genetic isolation of the freshwater populations, as they remain capable of surviving in salt water
Seawater
Seawater is water from a sea or ocean. On average, seawater in the world's oceans has a salinity of about 3.5% . This means that every kilogram of seawater has approximately of dissolved salts . The average density of seawater at the ocean surface is 1.025 g/ml...
. Freshwater Atlantic stingrays have only 30-50% the concentration of urea
Urea
Urea or carbamide is an organic compound with the chemical formula CO2. The molecule has two —NH2 groups joined by a carbonyl functional group....
and other osmolyte
Osmolyte
Osmolytes are compounds affecting osmosis. They are soluble in the solution within a cell, or in the surrounding fluid, e.g. as plasma osmolytes. They play a role in maintaining cell volume and fluid balance. For example, when a cell swells due to external osmotic pressure, membrane channels open...
s in their blood compared to marine populations. However, the osmotic pressure
Osmotic pressure
Osmotic pressure is the pressure which needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane....
between their internal fluids and external environment still causes water to diffuse
Osmosis
Osmosis is the movement of solvent molecules through a selectively permeable membrane into a region of higher solute concentration, aiming to equalize the solute concentrations on the two sides...
into their bodies, and they must produce large quantities of dilute urine
Urine
Urine is a typically sterile liquid by-product of the body that is secreted by the kidneys through a process called urination and excreted through the urethra. Cellular metabolism generates numerous by-products, many rich in nitrogen, that require elimination from the bloodstream...
(at 10 times the rate of marine individuals) to compensate.
Like other stingrays, the Atlantic stingray is ovoviviparous. Both marine and freshwater populations in Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
have an annual mating season from September or October to April, though ovulation
Ovulation
Ovulation is the process in a female's menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum . Ovulation also occurs in the estrous cycle of other female mammals, which differs in many fundamental ways from the menstrual cycle...
does not occur until late March or early April. Courtship involves the male following the female and biting at her body and fins, and the male will grip onto the female's pectoral fin to assist in copulation. The embryo
Embryo
An embryo is a multicellular diploid eukaryote in its earliest stage of development, from the time of first cell division until birth, hatching, or germination...
s are sustained by a yolk sac
Yolk sac
The yolk sac is a membranous sac attached to an embryo, providing early nourishment in the form of yolk in bony fishes, sharks, reptiles, birds, and primitive mammals...
until around day 60, after which they are nourished by uterine milk secreted by the mother. Litters of 1-4 young are born from late July to early August, after a gestation period
Gestation period
For mammals the gestation period is the time in which a fetus develops, beginning with fertilization and ending at birth. The duration of this period varies between species.-Duration:...
of 4-4.5 months. Newborns measure 10–13 cm (3.9–5.1 in) wide. Marine males mature at a disk width of 20 cm (7.9 in) and females at a disk width of 24 cm (9.4 in). Freshwater males mature at a disk width of 21 cm (8.3 in) and females at a disk width of 22 cm (8.7 in).
Human interactions
If stepped on, the Atlantic stingray can inflict a painful, though rarely life-threatening wound. Large numbers of Atlantic stingrays are caught as bycatchBycatch
The term “bycatch” is usually used for fish caught unintentionally in a fishery while intending to catch other fish. It may however also indicate untargeted catch in other forms of animal harvesting or collecting...
in gillnet
Gillnet
Gillnetting is a common fishing method used by commercial and artisanal fishermen of all the oceans and in some freshwater and estuary areas. The gillnet also is used by fisheries scientists to monitor fish populations. Because gillnets can be so effective their use is closely monitored and...
s targeting flounder
Flounder
The flounder is an ocean-dwelling flatfish species that is found in coastal lagoons and estuaries of the Northern Atlantic and Pacific Oceans.-Taxonomy:There are a number of geographical and taxonomical species to which flounder belong.*Western Atlantic...
off North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...
, but most are released alive. They are also caught as bycatch in small numbers in recreational and commercial trout
Trout
Trout is the name for a number of species of freshwater and saltwater fish belonging to the Salmoninae subfamily of the family Salmonidae. Salmon belong to the same family as trout. Most salmon species spend almost all their lives in salt water...
gillnets, shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
drift net
Drift net
Drift netting is a fishing technique where nets, called drift nets, are allowed to float freely at the surface of a sea or lake. Usually a drift net is a gill net with floats attached to a rope along the top of the net, and weights attached to another rope along the foot of the net to keep the net...
s, and nearshore trawls. As there is no fishery
Fishery
Generally, a fishery is an entity engaged in raising or harvesting fish which is determined by some authority to be a fishery. According to the FAO, a fishery is typically defined in terms of the "people involved, species or type of fish, area of water or seabed, method of fishing, class of boats,...
targeting this species and bycatch mortality appears to be low, it was assessed as of Least Concern
Least Concern
Least Concern is an IUCN category assigned to extant taxon or lower taxa which have been evaluated but do not qualify for any other category. As such they do not qualify as threatened, Near Threatened, or Conservation Dependent...
by the World Conservation Union
World Conservation Union
The International Union for Conservation of Nature and Natural Resources is an international organization dedicated to finding "pragmatic solutions to our most pressing environment and development challenges." The organization publishes the IUCN Red List, compiling information from a network of...
. However, some localized freshwater populations have shown reduced health and reproduction due to declining water quality.