Silver Redhorse

Silver Redhorse
Silver redhorse (Moxostoma anisurum)
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Cypriniformes
Family:	Catostomidae
Genus:	Moxostoma
Species:	M. anisurum
Binomial name
Moxostoma anisurum (Rafinesque, 1820)

The Silver Redhorse, Moxostoma anisurum, is a species of freshwater fish endemic to Canada from Quebec to Alberta and in the United States in the Mississippi River, St. Lawrence River, Ohio River, and the Great Lakes basins. It is typically found in lakes and in small to large rivers, where it often lives in undercut banks or protruding tree roots.

A bottom-feeder, it feeds on mollusks, algae, detritus, immature insects, and other small organisms.

Abstract

The Silver Redhorse (Moxostoma anisurum) is slowing becoming more and more rare in the rivers and lakes across the southeast. It is considered threatened in the state of Arkansas by the Nature Conservancy ^[1]. The reasons for their decline vary from year to year, but one theory from 2003 stands out from the rest. Weyers, Jennings, and Freeman conclude that the high-velocity, pulsed water flow that makes its way downstream from hydropower-generating dams has been the leading reason for decline in the species ^[2]. With these problems happening primarily in the south, the Silver Redhorse (Moxostoma anisurum) seems to thrive better in the far north. Comtois claims that in Quebec, Canada 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 ^[3]. These observations which were recorded in 2004 were greatly useful to the understanding of reproduction the Silver Redhorse. But before these findinds surfaced, it was an electrophoretic study of the Silver Redhorse that gave the scientific world an idea of the species reproductive status. In 1983 Morgan, Smith, and Stauffer concluded that the protein composition of the species larvae had a direct comparative link to the gradient electrophoresis used to separate the larvae ^[4]. One year previous, in 1982, 2 new species (Pseudomurraytrema milleri) and (Pellucidhaptor moxostomi) are recorded to be a branch or sub-species of the Silver Redhorse. Mergo and White state that the gills of both the Pseudomurraytrema milleri and the Pellucidhaptor moxostomi are directly connected to those of the Silver Redhorse (Moxostoma anisurum) ^[5].

Geographic Distribution of Species

The distribution of the Silver Redhorse (Moxostoma anisurum) is widely focused in the eastern half of the United States from Missouri all the way to Quebec Canada ^[1]. Although the distribution may seem extremly vast, the majority of the species is harbored in the southeastern states. The species itself is quite abundant in most southeastern rivers including the Mississippi, Missouri, and Ohio river systems ^[1]. With that being said, not all the river basins are abundant in this Redhorse species. The Silver Redhorse (Moxostoma anisurum) is actually listed as threatened in the Strawberry River basin in Arkansas. And although the reasons behind these lack of numbers is not pinpointed, it may be that the competetition between other Moxastoma species in this specific River is to blame. The distribution of the species is a direct effect on how well it thrives in a vast array of habitat. So for a species to do better in one area than it does in another is indeed why the so called term "threatened" is place on that species in that area.

Ecology

A vital part of any species existence is its diet. And not only what does it eat, but what effects its eating habits as well. For the Silver Redhorse (Moxostoma anisurum) these principles are no different. The species feeds on small vegetation and insects that are present in its immediate habitat. But what most do not understand is what can affect the way these species forage. The high-velocity water flow patterns in some water ways can actually damage the forage for this specific species ^[2]. But not all effects of high-velocity water flow are seen as damaging. A study concluded that the high-velocity water flow actually helped reproduction and larvae mortality by having a 90% success rate ^[2]. Temperature can also hold a very significant role in reproduction and success for the species in every environment, proving that every stage of reproduction is different depending on where the species is located at what times of the year. Nest succession plays as the deciding factor on how well this species thrives in high-velocity water systems.

Life History

The Silver Redhorse (Moxostoma anisurum) generally spawns in the spring in or around April or May ^[3]. This specific species usually spawns at night in the shallow waters of most river beds and gravel bottom flats. Reproduction maturity for the species happens late in its life usually at around 4 to 5 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 history of the Silver Redhorse is directly involved with the overall success of its survival in any given circumstance, therefore producing more offspring in a specific area of interest. The life span average for the species is somewhere around 10–12 years with 14 being the maximum. This is extremely important when given the overall look at year in and year out reproduction succession. A species that grows to be of that age can positively effect the succession of the next generation Silver Redhorses.

Current Management

The current management for the Silver Redhorse (Moxostoma anisurum) is not important to most wildlife and fisheries biologists across the country. There is virually no human impact on the species that can damage any amount of its presents in the lakes and river systems across the country. The species is known to help the lakes and river systems grow, and usually when a person sees a Silver Redhorse in a lake or river that indicates a healthy water system. The Silver Redhorse is mostly abundant in the southeastern river basins, but is threatened in the state of Arkansas, namely the Strawberry River ^[1]. But although the species is threatened in that area, there is no indicator that can tell biologists the reason for its decline. An upside to the species survival is that it is not commercially or recreationally fished for through most the areas in which it inhabits. Plus there have been advances in the technology that can electrically enhance larval succession in the species ^[4]. So there are no true threats to harm the species itself. Therefore the species can ultimately thrive in mostly every stage of its life. There is simply no match for this species in its environment, no real predators due to its large size(18–24 in), and no real threat towards its continued reproductive succession. This species seems to have everything to gain and nothing to lose according to its past survival rates and lengthy life span. There is no greater feeling than being able to live through the stages of life and never having to worry about survival being an issue.

Management Recommendations

The Silver Redhorse in its native range, is widely abundant throughout the waterways in which it occupies. The species has actually been abundant enough to produce multiple other species due to cross-breeding ^[5]. These different species have made a huge impact on the ongoing diversification of the original species itself. To further look into the existence of the Silver Redhorse, it has to be monitored for the future to successfully capture its growth. There should be teams across the species range that monitor the succession of the species, and how much effect that has on a certain lake or river basin. Monitor the size and movement of the species from year to year; tag the fish to see where they are located throughout different seasons of the year. Also measure the larval movement from season to season to indicate how well the mortality rate is. Sample the genders in specific areas of the range to indicate the ratios between male vs female, and how that can effect reproduction status. Use seines and electroshockers to access the species in adjacent river basins to measure their growth across distances and river chains. It would be efficient to sample every spring and fall of the year. After the sampling is done, use the information to indicate which waterways need to be protected, and which of them need to be controlled. Invasive species for the most part have no effect of the Silver Redhorse of current knowledge, though a plan always needs to be in place in case of an outbreak of pollution, or even disease. The Silver Redhorse is an extremely strong and abundant species through the eastern half of the United States and southern Canada. There all always going to be different ways of keeping the species up to date, and the information new. The species as of today is moving forward with a bright future ahead. The only thing that could stop the look at production of this species is if the world runs out of biologists to carry out the research. Lets hope there never comes such a day.

Sources

• "Moxostoma anisurum". Integrated Taxonomic Information System. http://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=163933. Retrieved 6 June 2006. 
• Froese, Rainer, and Daniel Pauly, eds. (2005). "Moxostoma anisurum" in FishBase. November 2005 version.
• NatureServe - Moxostoma anisurum

References

1. ^ ^{a b c d} McAllister, Chris T. et al "DISTRIBUTION OF THE SILVER REDHORSE, MOXOSTOMA ANISURUM (CYPRINIFORMES: CATOSTOMIDAE), IN ARKANSAS." Southwestern Naturalist 54.4 (2009): 514-518. Print
2. ^ ^{a b c} Weyers, R. S., C. A. Jennings, and M. C. Freeman "Effects of Pulsed, High-velocity Water Flow on Larval Robust Redhorse and V-lip Redhorse." TRANSACTIONS OF THE AMERICAN FISHERIES SOCIETY 132.1 (2003): 84-91. Print
3. ^ ^{a b} Comtois, A. et al "The Spring Survey of a Multi-specific Spawning Ground: The Ichtyofauna of the Rapids of the Gatineau River, Quebec." CANADIAN FIELD-NATURALIST 118.4 (2004): 521-529. Print
4. ^ ^{a b} Morgan, R. P., R. E. Smith, and J. R. Stauffer "ELECTROPHORETIC SEPARATION OF LARVAL SILVER REDHORSE (MOXOSTOMA-ANISURUM) AND GOLDEN REDHORSE (MOXOSTOMA-ERYTHRURUM)." COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY B-BIOCHEMISTRY & MOLECULAR BIOLOGY 76.4 (1983): 721-722. Print
5. ^ ^{a b} 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. Print