Macrobrachium ohione
Encyclopedia
Macrobrachium ohione, commonly known as the Ohio shrimp or Ohio River shrimp, is a species of freshwater
shrimp
found in rivers throughout the Gulf of Mexico
and Atlantic Ocean
drainage basin
s. It is commonly used as bait
for commercial fishing, especially catfish
. It is the best-known of all North American freshwater shrimp.
ed, with the second pair larger than the first. The rostrum
is curved and contains up to 13 teeth.
to Florida
on the Atlantic coast of North America, and from the southern tip of Missouri
to Louisiana
further westward. Despite the common name, the Ohio shrimp is not generally found in the Ohio River
anymore. Until the 1930s, it was common in the Ohio River, with the type specimen having been taken at Cannelton, Indiana
, and its range in the Mississippi River
extended as far north as St. Louis, Missouri
. Dam
s, interbasin transfer
of water, and other human activities are thought to be the cause for the decrease in range.
In May 2001, two specimens were found in the Ohio at Joppa, Illinois
, the first ones in 50 years, indicating either that the species is returning to its former range, or that prior sampling methods were ineffective.
e must live in saltwater and move to freshwater as adults. This is accomplished by having the larvae drift, free-floating, down the river until they reach water where the salinity
is high enough to support them. Females carrying eggs may also migrate downstream before releasing the larvae to reduce the time required for travel. A 2008 study by the University of Louisiana at Lafayette
discovered that M. ohione larvae are viable for up to five days in freshwater. After this, the likelihood of their molting
and surviving in saltwater is drastically diminished. The researchers concluded that dams and other human-erected barriers, by blocking the larval drift, are likely to be the primary reason that Ohio River shrimp are almost non-existent in the Ohio River.
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...
shrimp
Shrimp
Shrimp are swimming, decapod crustaceans classified in the infraorder Caridea, found widely around the world in both fresh and salt water. Adult shrimp are filter feeding benthic animals living close to the bottom. They can live in schools and can swim rapidly backwards. Shrimp are an important...
found in rivers throughout 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...
and Atlantic Ocean
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...
drainage basin
Drainage basin
A drainage basin is an extent or an area of land where surface water from rain and melting snow or ice converges to a single point, usually the exit of the basin, where the waters join another waterbody, such as a river, lake, reservoir, estuary, wetland, sea, or ocean...
s. It is commonly used as bait
Fishing bait
Fishing bait is any substance used to attract and catch fish, e.g. on the end of a fishing hook, or inside a fish trap. Traditionally, nightcrawlers, insects, and smaller bait fish have been used for this purpose...
for commercial fishing, especially catfish
Catfish
Catfishes are a diverse group of ray-finned fish. Named for their prominent barbels, which resemble a cat's whiskers, catfish range in size and behavior from the heaviest and longest, the Mekong giant catfish from Southeast Asia and the second longest, the wels catfish of Eurasia, to detritivores...
. It is the best-known of all North American freshwater shrimp.
Description
M. ohione is pale gray with small blue spots and grows up to 10 cm (4 in) long. Its first two pairs of legs are clawClaw
A claw is a curved, pointed appendage, found at the end of a toe or finger in most mammals, birds, and some reptiles. However, the word "claw" is also often used in reference to an invertebrate. Somewhat similar fine hooked structures are found in arthropods such as beetles and spiders, at the end...
ed, with the second pair larger than the first. The rostrum
Rostrum (anatomy)
The term rostrum is used for a number of unrelated structures in different groups of animals:*In crustaceans, the rostrum is the forward extension of the carapace in front of the eyes....
is curved and contains up to 13 teeth.
Distribution
The species may be found from North CarolinaNorth 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...
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...
on the Atlantic coast of North America, and from the southern tip of Missouri
Missouri
Missouri is a US state located in the Midwestern United States, bordered by Iowa, Illinois, Kentucky, Tennessee, Arkansas, Oklahoma, Kansas and Nebraska. With a 2010 population of 5,988,927, Missouri is the 18th most populous state in the nation and the fifth most populous in the Midwest. It...
to Louisiana
Louisiana
Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...
further westward. Despite the common name, the Ohio shrimp is not generally found in the Ohio River
Ohio River
The Ohio River is the largest tributary, by volume, of the Mississippi River. At the confluence, the Ohio is even bigger than the Mississippi and, thus, is hydrologically the main stream of the whole river system, including the Allegheny River further upstream...
anymore. Until the 1930s, it was common in the Ohio River, with the type specimen having been taken at Cannelton, Indiana
Cannelton, Indiana
Cannelton is a city in Troy Township, Perry County, Indiana, United States, along the Ohio River. The population was 1,209 at the 2000 census. Cannelton, which is the smallest incorporated city in the state, was formerly the county seat of Perry County until the seat was relocated to Tell City...
, and its range in 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...
extended as far north as St. Louis, Missouri
St. Louis, Missouri
St. Louis is an independent city on the eastern border of Missouri, United States. With a population of 319,294, it was the 58th-largest U.S. city at the 2010 U.S. Census. The Greater St...
. Dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...
s, interbasin transfer
Interbasin transfer
Interbasin transfer or transbasin diversion are terms used to describe man-made conveyance schemes which move water from one river basin where it is available, to another basin where water is less available or could be utilized better for human development...
of water, and other human activities are thought to be the cause for the decrease in range.
In May 2001, two specimens were found in the Ohio at Joppa, Illinois
Joppa, Illinois
Joppa is a village in Massac County, Illinois, along the Ohio River. The population was 409 at the 2000 census. It is part of the Paducah, KY-IL Micropolitan Statistical Area.-Geography:Joppa is located at ....
, the first ones in 50 years, indicating either that the species is returning to its former range, or that prior sampling methods were ineffective.
Reproduction
Like other Macrobrachium species, the Ohio shrimp is amphidromous. The larvaLarva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
e must live in saltwater and move to freshwater as adults. This is accomplished by having the larvae drift, free-floating, down the river until they reach water where the salinity
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...
is high enough to support them. Females carrying eggs may also migrate downstream before releasing the larvae to reduce the time required for travel. A 2008 study by the University of Louisiana at Lafayette
University of Louisiana at Lafayette
The University of Louisiana at Lafayette, or UL Lafayette, is a coeducational, public research university located in Lafayette, Louisiana, in the heart of Acadiana...
discovered that M. ohione larvae are viable for up to five days in freshwater. After this, the likelihood of their molting
Ecdysis
Ecdysis is the moulting of the cuticula in many invertebrates. This process of moulting is the defining feature of the clade Ecdysozoa, comprising the arthropods, nematodes, velvet worms, horsehair worms, rotifers, tardigrades and Cephalorhyncha...
and surviving in saltwater is drastically diminished. The researchers concluded that dams and other human-erected barriers, by blocking the larval drift, are likely to be the primary reason that Ohio River shrimp are almost non-existent in the Ohio River.