The chestnut lamprey (''Ichthyomyzon castaneus'') is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

lamprey Lampreys (sometimes inaccurately called lamprey eels) are an ancient extant lineage of jawless fish of the order Petromyzontiformes , placed in the superclass Cyclostomata. The adult lamprey may be characterized by a toothed, funnel-like s ...

Description

The chestnut lamprey has a maximum length of around , in

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

, with dark grey to olive skin color, blue-black after

spawning Spawn is the eggs and sperm released or deposited into water by aquatic animals. As a verb, ''to spawn'' refers to the process of releasing the eggs and sperm, and the act of both sexes is called spawning. Most aquatic animals, except for aquat ...

, and with five to eight

bicuspid The premolars, also called premolar Tooth (human), teeth, or bicuspids, are transitional teeth located between the Canine tooth, canine and Molar (tooth), molar teeth. In humans, there are two premolars per dental terminology#Quadrant, quadrant in ...

laterals around its mouth. The chestnut lamprey is closely related to the nonparasitic southern brook lamprey, and the two have been termed a paired species.

Distribution and habitat

The range of the chestnut lamprey extends from

Lake Winnipeg Lake Winnipeg (french: Lac Winnipeg, oj, ᐑᓂᐸᑲᒥᐠᓴᑯ˙ᑯᐣ, italics=no, Weenipagamiksaguygun) is a very large, relatively shallow lake in North America, in the province of Manitoba, Canada. Its southern end is about north of t ...

and the Hudson Bay down the

Mississippi River The Mississippi River is the second-longest river and chief river of the second-largest drainage system in North America, second only to the Hudson Bay drainage system. From its traditional source of Lake Itasca in northern Minnesota, it fl ...

to the Central and

Eastern United States The Eastern United States, commonly referred to as the American East, Eastern America, or simply the East, is the region of the United States to the east of the Mississippi River. In some cases the term may refer to a smaller area or the East C ...

; this includes any large lakes or

reservoir A reservoir (; from French ''réservoir'' ) is an enlarged lake behind a dam. Such a dam may be either artificial, built to store fresh water or it may be a natural formation. Reservoirs can be created in a number of ways, including contro ...

s where large host fish are present. In Canada, the chestnut lamprey has been found in

Saskatchewan Saskatchewan ( ; ) is a province in western Canada, bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and on the south by the U.S. states of Montana and North Dak ...

Manitoba , image_map = Manitoba in Canada 2.svg , map_alt = Map showing Manitoba's location in the centre of Southern Canada , Label_map = yes , coordinates = , capital = Winn ...

Ontario Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central C ...

, and

Quebec Quebec ( ; )According to the Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is one of the thirtee ...

Ecology

Adults are

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson ha ...

and feed on larger species of fish to support their body. It was widely presumed that this fish did not feed during the winter, but recent research in

Wisconsin Wisconsin () is a state in the upper Midwestern United States. Wisconsin is the 25th-largest state by total area and the 20th-most populous. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake M ...

has revealed some lampreys remain attached to their host during the winter months; one fisherman caught a sturgeon with a chestnut lamprey still attached. Observation of this species has revealed that they are primarily a nocturnal animal and they seek out shade during daylight. These lampreys may be beneficial to the rivers and lakes, due to their natural control of local fish populations. Human populations can pose threats to these animals through

pollution Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, the ...

siltation Siltation, is water pollution caused by particulate Terrestrial ecoregion, terrestrial Clastic rock, clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments and to the ...

, and dredging. Larval lamprey must

filter feed Filter feeders are a sub-group of suspension feeding 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 feedin ...

for numerous years and are vulnerable to changes in their environment during this time. For instance, larval lampreys will starve if large particulate matter regularly block their mouths.

Life history

During the egg stage of the lamprey's life, it is vulnerable to

predator Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

s that prefer to eat fish eggs. Predation by other fish helps keep the lamprey numbers under control. When the lamprey has hatched from its egg into the larvae stage, it is limited to pools or backwater areas with a sand or sandy mud bottom. The young lampreys filter feed for food for around five to seven years until they are large enough to attach themselves to a host species. Spawning of this species of lamprey occurs from June to July when the animals are around seven to nine years old and migrate to tributaries to protect the young from predators, though most spawning activity has been observed in mid-June. During the mating process, one female would begin moving rocks from a suitable area for eggs; afterward she attaches herself to a rock while hopeful males attach to her and stroke her tail attempting to mate. The eggs are then covered with a rock, presumably to shade the young lampreys at birth and to keep any predators from devouring the young. As with most lampreys, the chestnut lamprey only mates once during its entire life and dies shortly after.

References

{{DEFAULTSORT:Chestnut Lamprey Ichthyomyzon Fish described in 1858 Animal parasites of fish