The common name of Lepomis gulosus is the warmouth. It is one of the 324 fish species found in 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...

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Introduction

The following is a description of a monitoring plan for the Warmouth (Lepomis gulosus). One of the eleven species in the Lepomis genus, the species name gulosus refers to the warmouths big eyes. The species is native to the Mississippi and the Great Lakes basins, as well as brackish water areas in the Atlantic and Gulf Coast drainages. The warmouth is often found in slower moving streams or backwater areas.
The following monitoring plan for the warmouth will include geographic distribution, ecology, life history, current management and management recommendations. The geographic distribution will include the species current ranges as well as its historic ranges, and if there have been any changes in the species ranges. The ecology will discuss the species occurrence and what micro-habitat factors could influence the species presence. This will also include what predators and competing could influence the warmouths presence. The life history will describe the species reproductive strategies and other factors that influence the life of the warmouth. This will include factors that affect nesting success such as water velocity, temperature, bottom substrate and overall lifespan of the warmouth. Current management will include what human induced factors are negatively affecting the warmouth, such as habitat loss and siltation due human presence. Management recommendations will include what types of sampling techniques that would be most effective to monitor the species distribution and density. By sampling the population strategies can be created to insure good overall species health for the future.

Geographic Distribution of Species

This species is native and found throughout the much of the south in the Mississippi River drainage; existing all the way to the Gulf and Atlantic Coasts and Northward to the Chesapeake Bay. As well as being found westward throughout Texas to the Rio Grande, and northward into the Great Lakes basin area . The warmouth prefers slower moving, back water streams and can often survive in streams with low oxygen levels where other species of sunfish cannot. Studies also show that the species exists with breeding populations in southern portions of Canada . According to Crossman, there is a likely chance that the species may have existed there for many years prior to being detected .

Ecology

The primary diet of the warmouth consists of insects, crayfish and other fishes . In a study by Willis , the largest factor affecting warmouth density and biomass in Florida’s lakes is the availability of aquatic macrophytes, which allows the fish to ambush prey and use as areas to spawn. The primary diet of young warmouth is on microcrustaceans and on aquatic insect lava. Whereas larger specimens tend to mainly consume crayfish, freshwater shrimp and other small fish . Their predators include larger fish, snakes, turtles, alligators, and birds. The primary habitats the warmouth occupies are areas with ample vegetation as cover with slower moving water, often around stumps, brush piles and other dense entanglements that allow the warmouth the ability to ambush prey yet escape larger predators that may threaten them .

Life History

Spawning for the warmouth begins usually begins when water temperatures reach 21.1 degrees C .Their spawning often begins in May and lasts until July. Nests are primarily constructed on rock or gravel substrates, usually located in or near to some type of structure in the water column. Unlike most other Lepomis species, the warmouth does not nest in a colony unless ideal nesting habitat is limited. Males are most commonly found defending the nest for up to 5 days later until the fry has hatched . Young warmouth spend most of their time hiding under benthic substrate available to avoid predators. Most of which are considered sexually mature after one year, however, Larimore states that it is often the size of a fish that states its maturity rather than time. Males usually grow large faster than females do. Different habitat conditions also reflect the lifespan of the warmouth, with a life span of 3-8 years .

Current Management

The warmouth is an extremely adaptable species that can survive in many different conditions, allowing it to exist in many river systems east of the Rocky Mountains. Often time the warmouth prefers habitats where slower moving and often polluted water. Often time this type of slower moving back water areas that the warmouth occupies allows pollutants to settle on in these areas. This could expose the fish to certain toxins that could threaten their health. This is more of a concern with the ever encroaching human developments.
The most common cause of concern for the warmouth is hybridization with other Lepomis spp. that often in habitats the areas as the warmouth. There are four species known that that the warmouth hybridizes with L. cyanellus and L. macrochirus, as well as two other species Largemouth bass Micropterus salmoides and Black crappie Pomoxis nigromaculatus .This does not seem to be a problem that is affecting the overall health or longevity of the species.

Management Recommendations

Since warmouths are a non-migratory fish, their populations should be relatively easily monitored throughout much of their existing ranges. According to Warren , there is no threat or current concern for the warmouth. To start this process, key areas of concern that have the potential to be hazardous for fish survival should be identified. These areas may be at risk for extreme pollutants, siltation, re-channelization, dam construction, over fishing or increasing exotic species. Often times these areas can be easily recognized and are more often negatively affecting the health of other species. Once these key areas of concern are identified, additional areas where there is no real threat or concern to fish health should also be identified. These areas should scattered across much of the fishes range and have the potential to give un-bias data sets as to the entire population. In an ideal management situation six types of each, concern or no concern, should be recognized in each state that the fish is native to. This will allow randomization throughout the monitoring of the species. Simple sampling techniques should be performed at each of these locations during the first calendar year. Techniques used should include a combination of elector shocking method and seine kick net methods. Note that many areas of the species habitat will require the use of a boat powered elector shocker. The seine nets will be mostly used for sampling after spawning when the young are living in the benthic substrate. This will give an idea of how successful reproduction was for the giving year. Once sampling is completed data should be viewed for any variation throughout the set. To effectively “monitor” this species, sampling should be repeated every other year for ten years to accurately determine species current status. Once status of the species is established and termed stable, the population can then be put on an extended monitoring plan where the species is only sampled on a 5 year basis. Doing this will populations will give data trends, and the species will show any signs of distress throughout the entire species home range, therefore showing they key areas where management efforts of the species should be focused.