Higgins' eye pearly mussel
Encyclopedia
Lampsilis higginsii is a rare species of freshwater mussel known by the common name Higgins' eye pearly mussel. It is native to the United States, where it occurs in the Mississippi River
and the drainages of some of its tributaries
. It is threatened by the introduced
zebra mussel
(Dreissena polymorpha). It is a federally listed endangered species
of the United States.
This bivalve mollusc is in the family Unionidae
, the river mussels. It is oval in shape with a thick, heavy shell which is yellowish or brown, sometimes with greenish rays. It reaches up to 10.2 centimeters in length. The nacre
is white, sometimes tinged pink and partly iridescent.
The historical range of this species stretched along 850 kilometers of the Mississippi River from Prescott, Wisconsin
, to Louisiana, Missouri
, as well as nine tributaries of the Mississippi. Today it can be found in the Mississippi from La Crosse, Wisconsin
, to Muscatine, Iowa
, and two tributaries, the St. Croix and Wisconsin River
s. It has always been rare, but it experienced a large reduction in population after 1965, when it began to lose the northernmost and southernmost reaches of its distribution, a total of over 50% of its range. One cause of the drop in population was pollution
. The mussel is now extirpated
from the Illinois River
because of pollution. The habitat has been altered by impoundments, including dam
s and locks
. Sedimentation
may also have negatively affected the mussel. Overfishing
may have reduced the population, as well.
Today the worst threat to the species is the invasive species
invasion of the zebra mussel. Zebra mussels attach to the shells of this and other native mussels, deforming them, preventing them from moving, and preventing their filter feeding
. The zebra mussels can use up all the food in the vicinity and deplete the oxygen, and may also consume the native mussels' larva
e and sperm, preventing reproduction. Deposits of waste products degrade the habitat. Other invasive species include the Asian clam
(Corbicula fluminea), which competes with the native mussel and consumes its sperm, larvae, and juveniles. Some introduced species of fish may eat juvenile mussels.
During breeding, the male releases sperm and the female siphons it and keeps the fertilized eggs in her gills until they hatch. The glochidia
, or mussel larvae, are released and enter the bodies of host organisms, which are fish. Some fish hosts for the mussel are largemouth bass (Micropterus salmoides), smallmouth bass (M. dolomieu), walleye
(Sander vitreus), and yellow perch (Perca flavescens).
This mussel has been propagated in captivity and released into appropriate habitat in areas where it has been extirpated.
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...
and the drainages of some of its tributaries
Tributary
A tributary or affluent is a stream or river that flows into a main stem river or a lake. A tributary does not flow directly into a sea or ocean...
. It is threatened by the introduced
Introduced species
An introduced species — or neozoon, alien, exotic, non-indigenous, or non-native species, or simply an introduction, is a species living outside its indigenous or native distributional range, and has arrived in an ecosystem or plant community by human activity, either deliberate or accidental...
zebra mussel
Zebra mussel
The zebra mussel, Dreissena polymorpha, is a small freshwater mussel. This species was originally native to the lakes of southeast Russia being first described in 1769 by a German zoologist Peter Simon Pallas in the Ural, Volga and Dnieper rivers. They are still found nearby, as Pontic and Caspian...
(Dreissena polymorpha). It is a federally listed endangered species
Endangered species
An endangered species is a population of organisms which is at risk of becoming extinct because it is either few in numbers, or threatened by changing environmental or predation parameters...
of the United States.
This bivalve mollusc is in the family Unionidae
Unionidae
Unionidae is a family of freshwater mussels, the largest in the order Unionoida, the bivalve mollusks sometimes known as river mussels, naiads, or simply as unionids.The range of distribution for this family is world-wide...
, the river mussels. It is oval in shape with a thick, heavy shell which is yellowish or brown, sometimes with greenish rays. It reaches up to 10.2 centimeters in length. The nacre
Nacre
Nacre , also known as mother of pearl, is an organic-inorganic composite material produced by some mollusks as an inner shell layer; it is also what makes up pearls. It is very strong, resilient, and iridescent....
is white, sometimes tinged pink and partly iridescent.
The historical range of this species stretched along 850 kilometers of the Mississippi River from Prescott, Wisconsin
Prescott, Wisconsin
Prescott is a city in Pierce County, Wisconsin at the confluence of the St. Croix River and Mississippi River. The population was 4,258 at the 2010 census, making it the second-largest city in the county after River Falls, and the largest entirely within Pierce County.Prescott was home to the...
, to Louisiana, Missouri
Louisiana, Missouri
Louisiana is a city in Pike County, Missouri, United States. The population was 3,863 at the 2000 census, making it the largest city in Pike Couunty. Louisiana is located in northeast Missouri, on the Mississippi River south of Hannibal....
, as well as nine tributaries of the Mississippi. Today it can be found in the Mississippi from La Crosse, Wisconsin
La Crosse, Wisconsin
La Crosse is a city in and the county seat of La Crosse County, Wisconsin, United States. The city lies alongside the Mississippi River.The 2011 Census Bureau estimates the city had a population of 52,485...
, to Muscatine, Iowa
Muscatine, Iowa
Muscatine is a city in Muscatine County, Iowa, United States. The population was 22,886 in the 2010 census, an increase from 22,697 in the 2000 census. It is the county seat of Muscatine County...
, and two tributaries, the St. Croix and Wisconsin River
Wisconsin River
-External links:* * * , Wisconsin Historical Society* * * *...
s. It has always been rare, but it experienced a large reduction in population after 1965, when it began to lose the northernmost and southernmost reaches of its distribution, a total of over 50% of its range. One cause of the drop in population was pollution
Pollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
. The mussel is now extirpated
Local extinction
Local extinction, also known as extirpation, is the condition of a species which ceases to exist in the chosen geographic area of study, though it still exists elsewhere...
from the Illinois River
Illinois River
The Illinois River is a principal tributary of the Mississippi River, approximately long, in the State of Illinois. The river drains a large section of central Illinois, with a drainage basin of . This river was important among Native Americans and early French traders as the principal water route...
because of pollution. The habitat has been altered by impoundments, including 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 and locks
Locks
Locks may refer to*Lock, a fastening device*Locks of hair*Dreadlocks, matted coils of hair, known as locks*Lock , a device for transferring vessels between bodies of water of different levels...
. Sedimentation
Sedimentation
Sedimentation is the tendency for particles in suspension to settle out of the fluid in which they are entrained, and come to rest against a barrier. This is due to their motion through the fluid in response to the forces acting on them: these forces can be due to gravity, centrifugal acceleration...
may also have negatively affected the mussel. Overfishing
Overfishing
Overfishing occurs when fishing activities reduce fish stocks below an acceptable level. This can occur in any body of water from a pond to the oceans....
may have reduced the population, as well.
Today the worst threat to the species is the invasive species
Invasive species
"Invasive species", or invasive exotics, is a nomenclature term and categorization phrase used for flora and fauna, and for specific restoration-preservation processes in native habitats, with several definitions....
invasion of the zebra mussel. Zebra mussels attach to the shells of this and other native mussels, deforming them, preventing them from moving, and preventing their filter feeding
Filter feeder
Filter feeders are animals that feed by straining suspended matter and food particles from water, typically by passing the water over a specialized filtering structure. Some animals that use this method of feeding are clams, krill, sponges, baleen whales, and many fish and some sharks. Some birds,...
. The zebra mussels can use up all the food in the vicinity and deplete the oxygen, and may also consume the native mussels' larva
Larva
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 and sperm, preventing reproduction. Deposits of waste products degrade the habitat. Other invasive species include the Asian clam
Corbicula fluminea
Corbicula fluminea is a species of freshwater clam, an aquatic bivalve mollusk in the family Corbiculidae.This species is of originally mainly Asian origin and thus it is often commonly called Asian clam or Asiatic clam. In the aquarium and koi pond trade it is often called Golden Clam or Golden...
(Corbicula fluminea), which competes with the native mussel and consumes its sperm, larvae, and juveniles. Some introduced species of fish may eat juvenile mussels.
During breeding, the male releases sperm and the female siphons it and keeps the fertilized eggs in her gills until they hatch. The glochidia
Glochidium
The glochidium is a special microscopic larval stage of larger freshwater mussels, aquatic bivalve mollusks in the families Unionidae and Margaritiferidae, the river mussels and European freshwater pearl mussels....
, or mussel larvae, are released and enter the bodies of host organisms, which are fish. Some fish hosts for the mussel are largemouth bass (Micropterus salmoides), smallmouth bass (M. dolomieu), walleye
Walleye
Walleye is a freshwater perciform fish native to most of Canada and to the northern United States. It is a North American close relative of the European pikeperch...
(Sander vitreus), and yellow perch (Perca flavescens).
This mussel has been propagated in captivity and released into appropriate habitat in areas where it has been extirpated.
External links
- Bogan, A.E. 1996. Lampsilis higginsii. 2011 IUCN Red List of Threatened Species. Downloaded on 14 September 2011.