Silver lamprey
Encyclopedia
The silver lamprey, or Ichthyomyzon unicuspis, is a lamprey
Lamprey
Lampreys are a family of jawless fish, whose adults are characterized by a toothed, funnel-like sucking mouth. Translated from an admixture of Latin and Greek, lamprey means stone lickers...

 found commonly in the Northern and Central United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...

 and a large part of southern Canada
Canada
Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

. Its binomial name means "fish to suck" in Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 and "one point" in Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

. The silver lamprey is a member of the Class Agnatha, sometimes referred to as cyclostomes (round-mouths). Other common names include: Bloodsucker, Blue Lamprey, Hitch-hiker, Lamper, Lamprey Eel. The silver lamprey should not to be confused with the sea lamprey (Petromyzon marinus) which has caused considerable damage to native fish stocks in the Great Lakes region.

Range/Distribution

The silver lamprey is commonly found along the Great Lakes
Great Lakes
The Great Lakes are a collection of freshwater lakes located in northeastern North America, on the Canada – United States border. Consisting of Lakes Superior, Michigan, Huron, Erie, and Ontario, they form the largest group of freshwater lakes on Earth by total surface, coming in second by volume...

 and 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...

 and 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...

 and their tributaries from Minnesota
Minnesota
Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...

 to Nebraska
Nebraska
Nebraska is a state on the Great Plains of the Midwestern United States. The state's capital is Lincoln and its largest city is Omaha, on the Missouri River....

, Tennessee
Tennessee
Tennessee is a U.S. state located in the Southeastern United States. It has a population of 6,346,105, making it the nation's 17th-largest state by population, and covers , making it the 36th-largest by total land area...

, and West Virginia
West Virginia
West Virginia is a state in the Appalachian and Southeastern regions of the United States, bordered by Virginia to the southeast, Kentucky to the southwest, Ohio to the northwest, Pennsylvania to the northeast and Maryland to the east...

. There have also been a small number of isolated encounters around the Hudson Bay
Hudson Bay
Hudson Bay , sometimes called Hudson's Bay, is a large body of saltwater in northeastern Canada. It drains a very large area, about , that includes parts of Ontario, Quebec, Saskatchewan, Alberta, most of Manitoba, southeastern Nunavut, as well as parts of North Dakota, South Dakota, Minnesota,...

 and 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...

 in Mississippi
Mississippi
Mississippi is a U.S. state located in the Southern United States. Jackson is the state capital and largest city. The name of the state derives from the Mississippi River, which flows along its western boundary, whose name comes from the Ojibwe word misi-ziibi...

.

Identification

The silver lamprey is an eel
Eel
Eels are an order of fish, which consists of four suborders, 20 families, 111 genera and approximately 800 species. Most eels are predators...

-like fish with an attenuate body composed of 49-52 clearly defined segments (i.e. myomeres, between the last gill slit and the anus). Silver lampreys possess a cartilaginous skeleton, and adults generally grow to a length of 12 inches and are silvery or bluish in color when spawning. Prior to spawning adults are often a dull brown or tan color. The dorsal fin
Dorsal fin
A dorsal fin is a fin located on the backs of various unrelated marine and freshwater vertebrates, including most fishes, marine mammals , and the ichthyosaurs...

 is continuous, though it may be notched. The mouth is a jawless, sucking disc, with unicuspid teeth arranged in circular rows and is in the inferior position. When expanded, the mouth is wider than the lamprey's body. The lamprey's gills are arranged in a straight line immediately behind the eye, and a single nostril is located between the eyes. Larvae are a brown to tan all over have no eyes (instead they have eyespots) and are called ammocoetes. They also have seven gill openings and do not have any paired fins, they have only a long continuous fin runs from the dorsal to the ventral side. Ammocoetes also have no teeth and instead have an oral hood which houses skin extensions that help them filter particles out of the water as they draw it into their oral cavity.

Habitat

Adult silver lampreys prefer the clear waters of large streams, rivers, and lakes. Adults migrate to nest in flowing water that has stoney or gravelly bottom material. The larvae, when they hatch, move to slow flow areas initially with thick organic layers, as they grow in size they begin to migrate to sandy environments where they will reside until they reach metamorphosis.

Diet

Adult silver lampreys are parasitic, feeding on the blood of other fishes. They use their oral discs to attach to their hosts, then cut through the skin and scales with their teeth. The lamprey will remain attached to the host over a long period of time, but they seldom kill their host (which have coevolved with these lampreys). Adults feed on a variety of fishes, including 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...

, Whitefish
Whitefish
Whitefish or white fish may refer to:In fishing terminology:* Whitefish , a fisheries term referring to the flesh of many types of fishIn fish species:...

, Smelt, Pike
Pike
-Transit:*Pike or toll road, a course in which fees are collected. Sometimes a historical name of what once was a toll road.-Fish:*Esox, genus of pikes**Northern pike, common north hemisphere pike*Blue pike or blue walleye, an extinct freshwater fish...

, White Sucker
White Sucker
The White Sucker is a bottom-feeding freshwater fish inhabiting North America from Labrador in the north to Georgia and New Mexico in the south. It is a long, round-bodied fish with a dark green, grey, copper, brown, or black back and sides and a light underbelly. When fullgrown, it is between 12...

, Brown Bullhead
Brown bullhead
The brown bullhead, Ameiurus nebulosus, is a fish of the Ictaluridae family that is widely distributed in North America. It is a species of bullhead catfish and is similar to the black bullhead and yellow bullhead...

, Rock Bass
Rock bass
The rock bass , also known as the rock perch, goggle-eye, or red eye is a species of freshwater fish in the sunfish family of order Perciformes. They are similar in appearance to smallmouth bass but are usually quite a bit smaller...

, 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...

, and the armored Lake Sturgeon
Lake sturgeon
The lake sturgeon is a North American temperate freshwater fish, one of about 20 species of sturgeon. Like other sturgeons, this species is an evolutionarily ancient bottomfeeder with a partly cartilaginous skeleton and skin bearing rows of bony plates...

. The silver lamprey's larval young feed on drifting plankton and detritus.

Reproduction and Life Cycle

Adult silver lampreys move upstream
Upstream
In geography, upstream literally means towards the source of a stream or river, or against the normal direction of water flow.Upstream is the opposite of downstream...

 to spawn in May and June, when the water temperature reaches 50º F. Using their mouths to move sand and gravel, they dig a nest in the stream bed
Stream bed
A stream bed is the channel bottom of a stream, river or creek; the physical confine of the normal water flow. The lateral confines or channel margins, during all but flood stage, are known as the stream banks or river banks. In fact, a flood occurs when a stream overflows its banks and flows onto...

. Once the nest is completed, the female attaches herself to a rock and the male attaches to her head, wrapping his tail around hers to bring the genitals close together. Eggs and sperm are released, then the pair separates. Once spawning is completed and the eggs are deposited in the nest, the adults die. Upon hatching, the larvae (called ammocoetes) are blind, toothless, and provided with a fine-mesh tissue sieve. They drift downstream
Downstream
-Science:* In geography, away from the source of a stream or river* In meteorology, away from the source of an air parcel or mass, along the normal direction of water or air flow* Downstream , in computer or telecommunications networks...

and burrow in the sand, mud, and organic material for 4-7 years. During this time, the ammocoetes feed mostly on detritus and algae. When they are approximately four to five inches long, the ammocoetes metamorphose into parasitic adults and migrate downstream to search for hosts. After one to two years feeding as a parasite, adult silver lampreys move upstream to spawn and die.
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