The silver redhorse (''Moxostoma anisurum'': Maxostoma= mouth to suck; anisurum = unequal tail) is a species of
freshwater
Fresh water or freshwater is any naturally occurring liquid or frozen water containing low concentrations of dissolved salts and other total dissolved solids. Although the term specifically excludes seawater and brackish water, it does include ...
fish endemic to
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 ...
and the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
.
[Phillips G., Schmid W., Underhill J. 1982. Fishes of the Minnesota Region. University of Minnesota. 162-163.] Sometimes called redhorse or sucker for short, it is in the family Catostomidae with other suckers. The species is distributed from
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 ...
to
Alberta
Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...
and is also in 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 f ...
,
St. Lawrence River
The St. Lawrence River (french: Fleuve Saint-Laurent, ) is a large river in the middle latitudes of North America. Its headwaters begin flowing from Lake Ontario in a (roughly) northeasterly direction, into the Gulf of St. Lawrence, connecting ...
,
Ohio River
The Ohio River is a long river in the United States. It is located at the boundary of the Midwestern and Southern United States, flowing southwesterly from western Pennsylvania to its mouth on the Mississippi River at the southern tip of Illino ...
, and the
Great Lakes
The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...
basins. The current world record is 14 pounds, 14 ounces, caught by Chris Stephenson on Pickwick Lake in Alabama, April 1995 and certified by National Freshwater Fishing Hall of Fame.
Morphology
The silver redhorse is silver on both sides and has a dark gray-brown back and a slate gray tail. The caudal fin is large and moderately forked. Each lobe of the fin is pointed and equal in size.
[Page L., Burr B. 1991. Freshwater Fishes. Lawrance M. Page and Brooks M. Buur. 186. Print] On the silver sides there are 41–42 cycloid lateral line scales.
The single dorsal fin does not have any dorsal spines, but instead contains 14–17 soft rays. Their dorsal fin is slightly convex (rounded outward) and is located approximately in the middle of the back. There is no adipose fin (unstructured fin found behind the rayed dorsal fin) present on the back of the fish. The mouth of the silver redhorse is in the inferior position, as it is a bottom feeder. The rear edge of the silver redhorse lips forms a deep "V". Because of extreme similarities, the silver red horse is commonly confused with the
Black redhorse and the
Golden redhorse
The golden redhorse, ''Moxostoma erythrurum'', is a species of freshwater fish endemic to Ontario and Manitoba in Canada and the Midwestern, southern, and eastern United States. It lives in calm, often silty or sandy waters in streams, small to ...
. However, both of these redhorses have slightly concave dorsal fins (curves in toward body) with only 12-14 fin rays. Additionally the Silver red horse is more deep-bodied than the golden or black redhorse. It typically weights 2–5 pounds and measures 18-24 inches long, but it can reach up to 10 pounds and 30 inches.
[http://wildlife.ohiodnr.gov/species-and-habitats/species-guide-index/fish/silver-redhorse]
Geographic distribution
The native range of the silver red horse is the great lakes and the St. Lawrence and Mississippi River basins. However, there have been instances in which the fish was found in Clayton lake and the New River Drainage in North Carolina.
The silver redhorse is also widely distributed in eastern North America from Missouri to Quebec with most residing in the southeastern United States.
[McAllister, Chris T. et al. "Distribution of the Silver Redhorse, Moxostoma Anisurum (Cypriniformes: Catostomidae), in Arkansas." ''Southwestern Naturalist'' 54.4 (2009): 514-518.] It is typically found in lakes and in small to large rivers, where it often lives in undercut banks or protruding tree roots. They are also found in deep pools with little to no current and a sand substrate at the bottom of the pool useful for burying their eggs.
They are a good indicator of water quality as they cannot tolerate murky water.
Diet
Due to its inferior mouth position, this fish is a bottom feeder. It feeds on
mollusks
Mollusca is the second-largest phylum of invertebrate animals after the Arthropoda, the members of which are known as molluscs or mollusks (). Around 85,000 extant species of molluscs are recognized. The number of fossil species is esti ...
,
algae,
detritus
In biology, detritus () is dead particulate organic material, as distinguished from dissolved organic material. Detritus typically includes the bodies or fragments of bodies of dead organisms, and fecal material. Detritus typically hosts commun ...
, immature
insects, and other small invertebrates.
Monogenea
Monogeneans are a group of ectoparasitic flatworms commonly found on the skin, gills, or fins of fish. They have a direct lifecycle and do not require an intermediate host. Adults are hermaphrodites, meaning they have both male and female reprod ...
parasites have been found in the gills of the silver redhorse.
[Mergo, J. C., and A. M. White "2 New Species of Dactylogyridae (Monogenea) from the Silver Redhorse, Moxostoma anisurum." ''Journal of Parasitology'' 68.5 (1982): 946-948.]
Life history
The silver redhorse generally spawns in the spring in or around April or May when the water temperatures reach around 53 degrees Fahrenheit.
[ They take advantage of the shallow landforms flowing channels, also known as riffles, and spawn at the top and the bottoms of the riffles at night. One study in Quebec, Canada found that the silver redhorse is abundant in what they call V-males, as they outnumber the females considerably. For every female on the spawning bed, there is a minimum of 2 males that are used to successfully reproduce.][Comtois, A. et al "The Spring Survey of a Multi-specific Spawning Ground: The Ichthyofauna of the Rapids of the Gatineau River, Quebec." ''Canadian Field-Naturalist'' 118.4 (2004): 521-529. Print] The common methodology includes two males pressing a female between them, causing a vibration to occur while the egg and the sperm are released. The females bury their eggs in the gravel and offer no further parental care. Reproduction maturity for the species happens late in its life usually around four to five years of age. The species thrives in deep bottomed lakes and river systems which promote optimal nest succession year in and year out. The life span for the species is somewhere around 10–12 years, with 14 being the maximum.[http://www.rook.org/earl/bwca/nature/fish/moxostomaan.html]
Relationship with humans
The species is quite abundant in southeastern rivers including the Mississippi, Missouri
Missouri is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it is bordered by eight states (tied for the most with Tennessee ...
, and Ohio river systems.[ The silver redhorse is not commercially or recreationally fished for through most of the areas in which it inhabits.. Currently, this species is of relatively low conservation concern and does not require significant protection or major management. Localized threats may exist, but on a range-wide scale no major threats are known.] However, the silver redhorse is listed as threatened in the Strawberry River basin in Arkansas.[ The IGFA all-tackle record stands at 11 lb, 7 oz caught from Plum Creek 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 ...
in 1985.
Sources
*
*
NatureServe - Moxostoma anisurum
References
{{Taxonbar, from=Q1144405
Moxostoma
Fish of Canada
Freshwater fish of North America
Fauna of North America
Fish described in 1820
Taxa named by Constantine Samuel Rafinesque