Percina evides

Percina evides
Scientific classification
Kingdom:	Animalia
Phylum:	Chordata
Class:	Actinopterygii
Order:	Perciformes
Family:	Percidae
Genus:	Percina
Species:	P. evides
Binomial name
Percina evides (Jordan & Copeland, 1877)

The Gilt darter (Percina evides) is one of the 324 fish species found in Tennessee.

Introduction

This is a description of a monitoring plan for the Gilt darter (Percina evides), a native fish of Tennessee. The Gilt darter is one of 47 species of fish in the genus Percina. The Gilt darter is found in the upper Mississippi River drainage from northern Alabama and northern Arkansas to New York and Minnesota. It requires clear, healthy streams with fast riffles, cobbled-bottom runs, and low siltation.

The monitoring plan for this darter species will cover its geographic distribution, ecology, life history, current management strategies, and future management recommendations. The geographic distribution of this species historically covered 18 states in the Mississippi River drainage, but this species is now believed to be extirpated from New York, Iowa, Illinois, and Indiana. The gilt darter is a benthic fish that feeds primarily on small aquatic insect larvae. It competes with other similar sized benthic fish, most commonly, other darter species. The gilt darter is a spring spawner, most often spawning in May, depending upon the location. The males defend a spawning a territory in sandy-gravelly riffles and the females lay up to 400 eggs. Males grow larger and more colorful than females but neither grows much larger than 80mm. Gilt darters are most impacted by siltation which covers their feeding and spawning grounds. This is not a well-known species and few management practices are in place to protect it. One gilt darter restoration has been successful on the Pigeon River in Tennessee. The future of this species is not clear. It is thriving in some states and still declining in others. Through watershed protection, stream bank restoration, future reintroductions, and water quality monitoring this species stands a chance to rebound.

Geographic Distribution of Species

As currently described, the gilt darter is found in the upper portions of the Mississippi River Basin of North America.^[1] It is found in western tributaries of the Mississippi River Basin from the White River in northern Arkansas to the St. Croix River of Minnesota and Wisconsin. Its Eastern Range extends from tributaries of the Tennessee River system in northern Alabama up to New York in the Ohio River system.^[1][2] It was also found in Indiana in the Maumee River system.^[1] Locally, the gilt darter is found regularly throughout Tennessee in appropriate, high quality habitats. This species is sensitive to siltation and can be extirpated from degraded streams. This species has been lost in several drainages of the Midwest due to stream degradation.^[3] According to Ohio’s Division of Wildlife the gilt darter has not been seen there since 1893. The last time the gilt darter was seen in Indiana was in 1977, and it is also believed to be extirpated from Illinois and New York.^[4]

Ecology

No quantitative diet analysis has been conducted on the gilt darter in Tennessee. However, in the Sunrise River of Minnesota, the diet was found to consist almost exclusively of immature mayflies (46% by number), dipterans (43%), and caddisflies (10%), but the composition varied seasonally and with age.^[5] A later study that included sites in the St. Croix River found the same dominant food types, although the relative contributions of each type varied considerably across sites.^[6] Dietary information on gilt darters from the Little Tennessee River showed a dependence on macro invertebrates. Specifically, midge, mayfly and caddis larvae were most preyed upon. During the warmer months, black fly larvae were also an important forage food.^[3] Snails have also been found in the stomach contents of this species.^[2] Gilt darters were observed following feeding logperch attempting to steal food as the logperch foraged along the bottom.^[3] Another dietary study of nine sympatric darter species in Pennsylvania showed dietary preferences of this species. Under the study conditions, the gilt darter revealed a very diverse diet containing 7-10 taxa of aquatic invertebrates. It also consumed larger prey and more fish eggs than other Etheostoma darter species it often associates with.^[7] Predators of the gilt darter would be any piscivorous fish living in the same habitat. Smallmouth bass (Micropterus dolomieu), walleye (Sander vitreus), sauger (Sander canadensis), and trout (Salmonidae family) likely prey upon this species opportunistically. The gilt darter competes with any other similar sized benthic fish that share the same habitat. Depending upon location, these would most commonly be other darters and logperches (Sculpins, minnows, and chubs would also compete for similar forage when they’re present). At one site in Indiana, the gilt darter was found in association with central stonerollers (Campostoma anomalum), suckermouth minnows (Phenacobius mirabilis), creek chubs (Semotilus atromaculatus), blacknose dace (Rhinichthys atratulus), silverjaw minnow (Notropis buccatus), bluntnose minnow (Pimephales notatus), sand shiner (Notropis stramineus), spotfin shiner (Cyprinella spiloptera), Johnny darter (Etheostoma nigrum), rainbow darter (Etheostoma caeruleum), and blackside darters (Percina maculata).^[4]

The gilt darter was found to prefer upland cool-water streams.^[3] Specifically, they are often found in areas of the stream with higher velocities and more cobble on the streambed. They were also found to prefer areas of the stream subject to higher erosion rates. Larger gilt darters were found more often around heterogeneous substrata and more boulders than smaller gilt darters.^[8]

Life History

The reproductive season of the gilt darter is in the spring. Southern populations have been reported to begin the breeding season earlier than northern populations. Ripe females were caught in Arkansas as early as late April and early May. In Virginia, gilt darters were reported to spawn in May. In Missouri, breeding males were reported to be found in late May.^[9] In Minnesota, breeding typically occurred over a 6-week period in June and July, although it began in middle May in one year. Water temperatures at the time of breeding were 16-23˚C.^[10] Breeding was observed in the Little River of Tennessee from early June through early July. Males were observed establishing specific territories for breeding.^[3] They were reported to spawn at temperatures of 17-20 degrees Celsius.^[2] Ideal spawning habitat was at the upper ends of riffles with sandy and gravelly bottoms interspersed with larger cobble.^[3] Females produced from 130-400 eggs which hatch and mature past the larval stage within 2 weeks. Male gilt darters grow faster and larger than females. They reach a length of around 70mm in their third year. Larger specimens, up to 94mm have been reported in the Ozarks.^[3]

Current Management

The gilt darter is one of the lesser known darter species. It has not enjoyed the fame of other darter species, such as the snail darter. As such, there has not been much emphasis on research related to this species. Its range has been quietly declining as siltation and pollution have caused local extirpations across its range. The gilt darter was once found in 18 states. It is now believed to be extirpated from 4 of them. It is only listed as an apparently secure species in 3 states (Tennessee, North Carolina, and Arkansas). The remaining 11 states list the gilt darter as vulnerable, imperiled, or critically imperiled.^[4][11][12] However, some fisheries biologists have taken notice of this decline and have developed new propagation techniques that are suitable for this species. One organization in particular, Conservation Fisheries, Incorporated (CFI) is at the forefront of restoration activities. A recent reintroduction project on the Pigeon River in Tennessee has successfully restored a gilt darter population where they were previously extirpated.^[11] This project was a joint-effort between the University of Tennessee and CFI. Biologists are hoping that information gained from this successful reintroduction will allow them to attempt restoration efforts in other states where the gilt darter has been extirpated but suitable habitat is available.

Management Recommendations

Collecting benthic riffle fish, such as the gilt darter, is most often done by kick-seining. This is accomplished by deploying a seine beneath or in a riffle and making sure the bottom of the seine is in contact with the streambed. The kickers (often stationed 10 meters above the seine) then start kicking and shuffling downstream quickly to the seine. This moves rocks and ideally causes these benthic fish to run downstream where they are captured with the seine. This can also be used in conjunction with a backpack shocker than stuns the fish and allows them to float into the seine. Another option is visual observation, via snorkeling. This method is effective in clear water with low velocity. However, the gilt darter often prefers high velocity riffles and often hides under rocks so this technique may not be as effective.^[13] Another option for sampling this species is using pre-positioned bottom samplers. These are in essence electro shockers that are approximately 1 meter square with a catch net attached to the downstream side. It is placed in the sampling area and the area is allowed to settle down for a predetermined length of time to allow the fish to become accustomed to it and avoid “fright-bias”.^[13] This has potential to evaluate microhabitat use and population estimates of gilt darters.

In conclusion, the gilt darter has been in decline for most of the last century. This is due to stream degradation from pollution, siltation, and impounding of watersheds. The most common factor in gilt darter declines is likely due to siltation. This means the best management option is to improve and fortify areas with high erosion potential in gilt darter habitat. However, recent advances in darter propagation by CFI and restoration activities by the University of Tennessee may give hope to gilt darter fans in the eastern United States. Watershed improvements and protection in the historic range of the gilt darter could allow for populations to be reestablished where the gilt darter was once a plentiful and colorful member of the watershed.

References

• http://www.bio.utk.edu/hulseylab/Fishlist.html