Crystal darter | |
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Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Actinopterygii |
Order: | Perciformes |
Family: | Percidae |
Genus: | Crystallaria |
Species: | C. asprella |
Binomial name | |
Crystallaria asprella (D. S. Jordan, 1878) | |
Synonyms [2] | |
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The crystal darter (Crystallaria asprella) is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. This small North American fish is found in small, moderate, and swift rivers in the drainage basins of the Mississippi and Ohio Rivers. [2] It is now extirpated from a majority of its range along the Ohio River.
The crystal darter can grow to 12 cm (5 in) in length. It is olive-colored to tan with four dark saddles extending downward to its lateral line, a brownish stripe, and a whitish belly. Its maximum reported age is three years. [3]
The historical range of the crystal darter included the Mississippi River basin, from Wisconsin and Indiana, southwards to southeastern Oklahoma, northern Louisiana, southern Mississippi, the Mobile Basin, Pascagoula, Pearl River, Florida, Alabama, and Mississippi. It is now absent from much of this range and is rare in Wisconsin, Minnesota, Iowa, and Missouri. It is found in swift-flowing streams with clear or slightly turbid water and moderately swift riffles, on small or medium-sized rivers with beds of sand or gravel. It is not found on silty bottoms or areas with vegetation. Individual fish often hide under stones or bury themselves in sand with just their eyes showing. [1]
One study focused on the Saline River, Arkansas, suggested that crystal darters spawn multiple times from January through mid-April. [4] Another study, conducted in Alabama, revealed conflicting evidence that suggested the onset of spawning begins in late February and lasts approximately one week in duration. [5] The explanation for such discrepancy in breeding season timing and length is unknown, however, Hubbs (1985) suggested a difference in latitudinal location could explain the variation. [5] Multiple males can copulate with one female at a time. [6] Juvenile crystal darters grow rapidly and reach sexual maturity before age one, but do not spawn until the following season. [4] Most females reach sexual maturity by 50 mm standard length, but males do not mature until they reach 61 mm standard length. [4] Males grow faster and, consequently, adults males are larger than females of the same age. The difference in growth rates and size is probably due to females allocating more of their energy for reproduction. [4] Clutch size ranges from 106 to 576 mature oocytes per female, and clutch size is positively correlated with fish length. [4] The crystal darter is sexually dimorphic and mature males possess longer soft dorsal and anal fins than females. [4]
The crystal darter burrows in sandy substrates with only its eyes protruding. [5] This behavior may have evolved to capture prey, avoid predators, or conserve energy. [5] In 1989, Robert Daniels conducted a study on a closely related species, the Eastern sand darter, Ammocrypta pellucida , to explain burying behavior, but rejected both the prey avoidance and prey capturing hypotheses. [7] He suggested that darters burrow in order to save energy while maintaining their position in the sandy substrate where they live. This behavior may be very important during periods of high or low flow, but can be exhibited at any time. [7] Results from Daniels' study may also explain burying behavior in the crystal darter. [7]
The crystal darter is susceptible to a number of threats including overexploitation, habitat degradation through pollution and siltation, and habitat modification through stream flow alterations and artificial impoundment. [5]
Small populations of the crystal darter can be affected by scientific or educational collecting. However, collection for research purposes is important in regard to gaining information critical to developing management and conservation strategies to protect the species. [5]
Percid species, such as the crystal darter, require clean gravel and sand substrates for reproduction and foraging for food sources. [8] This habitat requirement makes them sensitive to activities that cause pollution and siltation, such as mining, logging, natural gas exploration and extraction, and agriculture. Because crystal darters are geographically confined to a few freshwater systems with clear, fast-moving water they are particularly vulnerable to extinction when their limited habitat is degraded. [5]
Soil erosion due to intensive or inadequate agricultural and forestry practices and construction activities has amplified the natural effects of siltation in the water bodies that drain these areas. Increased fine sediment deposition in the water column results in increased turbidity and limited light penetration, which can potentially reduce primary productivity with resulting impacts on the rest of the trophic system, including a reduction in habitat for insectivore prey items. [9] High concentrations of fine sediment can also affect fish by reducing their rate of growth, decreasing their tolerance to disease or directly killing them by clogging gill rakers and filaments. Siltation also reduces the suitability of critical spawning habitat, and thus hinders the stability and growth of future populations. Siltation is particularly threatening to the crystal darter, because it relies on clean sand and gravel habitats to reproduce. In addition, natural fish migration patterns can be modified when certain areas of this route become uninhabitable. Finally, siltation negatively affects the efficiency of hunting in visual feeders, such as the crystal darter. [9]
Stream flow modification through channelization and dredging can also affect darter populations. These processes can alter hydrologic regimes by reducing flow velocity through the straightening and widening of channels. [5] Since the crystal darter prefers strong currents, converting fast moving streams into slower moving channels or pools through these modifications can reduce the amount of available habitat to the crystal darter. In addition to altering flow, these modifications also reduce habitat diversity. [5]
Artificial impoundments, such as dams, increase the amount of sedimentation in streams by drowning riffles and reducing flow, causing changes in substrate composition. [9] In addition to increasing the effects of siltation, impoundments fragment fish habitat. Fragmentation can affect immigration and emigration between populations, inhibiting connectivity and gene flow. Isolated populations become increasingly susceptible to environmental disturbances, and if these populations were extirpated new fishes would be unable to recolonize and counter these local extinctions. [5] Isolation to reduced ranges due to habitat fragmentation can also inhibit gene dispersal, consequently limiting genetic diversity which can lead to reduced fitness of populations. [10]
The crystal darter is listed as vulnerable by the IUCN on its Red List because of "a decline in area of occupancy, extent of occurrence and/or quality of habitat". [1] It is also listed as a special concern species by the Minnesota Department of Natural Resources [11] and the Arkansas Game and Fish Commission, [12] as an endangered species by the Wisconsin Department of Natural Resources [13] and the Missouri Department of Conservation, [14] as an extirpated species by the Illinois Department of Natural Resources, [15] and as a tier 1, or critically impaired, species by the Mississippi Department of Wildlife, Fisheries and Parks [16] because of "extreme rarity (five or fewer occurrences or very few remaining individuals or acres) or because of some factor(s) making it vulnerable to extirpation."
The crystal darter was first formally described as Pleurolepis asprellus by the American ichthyologist David Starr Jordan (1851–1931) with the type locality given as a small rocky tributary of the Mississippi River at Warsaw, Illinois. [17] When Jordan and his colleague, Charles Henry Gilbert (1859–1928) subsequently assigned Pleurolepis asprellus to the new genus Crystallaria in 1885 P. asprellus was its type species by monotypy. [18]
The snail darter is a small species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is found in East Tennessee freshwater in the United States and in small portions of northern Alabama and Georgia. First recorded in 1973, the snail darter was listed as endangered under the U.S. Endangered Species Act of 1973 by 1975. The species was at the center of a major environmental law controversy that involved a lawsuit seeking to halt the completion of Tellico Dam, which posed a risk of extinction for the snail darter by blocking its migratory route. The case was eventually appealed to the U.S. Supreme Court, which ruled on it in its 1978 decision Tennessee Valley Authority v. Hill.
The sauger is a freshwater perciform fish of the family Percidae that resembles its close relative, the walleye. The species is a member of the largest vertebrate order, the Perciformes. It is the most migratory percid species in North America. Saugers have two dorsal fins; the first is spiny and the posterior dorsal fin is soft-rayed. Their paired fins are in the thoracic position and their caudal fin is truncated, which means squared off at the corners, a characteristic of the family Percidae. Another physical characteristic of saugers is their ctenoid scales, which are common in advanced fishes. Saugers have a fusiform body structure, and as a result are well adapted predatory fishes and are capable of swimming into fast currents with minimal drag on their bodies. They may be distinguished from walleyes by the distinctly spotted dorsal fin, by the lack of a white splotch on the caudal fin, by the rough skin over their gills, and by their generally more brassy color, or darker color in some regions. The typical sauger is 300 to 400 g in weight.
The southern brook lamprey is a lamprey found in the Southern United States including Arkansas, Louisiana, Mississippi, Alabama, and Georgia. It is a jawless fish with a sucking mouth on one end of it. It can appear to be a small eel, since it is rarely longer than one foot in length.
The skipjack herring is a North American, migratory, fresh- and brackish water fish species in the herring family Alosidae. The name skipjack shad comes from the fact that it is commonly seen leaping out of the water while feeding. Other common names include blue herring, golden shad, river shad, Tennessee tarpon, and McKinley shad. The skipjack shad is restricted to the Gulf of Mexico drainage basins. Skipjack are found in clear to moderately turbid water in areas with flow. Because they are a migratory species, dams often impede their reproduction. Records suggest that this species was much more abundant in the Upper Mississippi River basin before it was impounded. Currently, skipjack is most abundant in the Upper Mississippi River below the mouth of the Ohio River. They are known as an "early-run" species as they migrate to spawn in the early spring.
Crystallaria is a genus of freshwater ray-finned fish which is classified in the subfamily Etheostomatinae, commonly known as the darters, part of the family Percidae which also includes the perches, ruffes and pikeperches. They are found in the Mississippi River basin from Ohio to Minnesota and in southern Mississippi, northern Louisiana, and southeastern Oklahoma, and on the Gulf Slope of Escambia, Mobile Bay, and the Pearl River drainages. They have now been extirpated from Ohio, Kentucky, Indiana, and Illinois.
The ashy darter is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is endemic to the eastern United States.
The eastern sand darter is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. The eastern sand darter is a relatively small fish, most plentiful in the Mississippi and Ohio Rivers, as well as Lake Champlain and the Great Lakes. It prefers sandy-bottomed streams and sandy shoals in the lakes. The eastern sand darter feeds on larvae of black flies and other small insects in the water. They also feed on zooplankton in small portions since their small mouth size limits their gape ability. Its average body size is around 1.5-2 in long, and it breeds in the spring and summer in sandy-bottomed waters.
The frecklebelly madtom is a species of fish in the family Ictaluridae endemic to the United States. Madtoms are in the genus Noturus, which is a group of catfish prevalent in North America. In 2023, the Upper Coosa River distinct population segment (DPS) of N. munitus was listed as federally threatened under the Endangered Species Act of 1973.
The bigeye shiner is a species of ray-finned fish in the genus Notropis. This fish is a slender, silvery minnow with a dusky lateral stripe and a maximum total length of about 80 mm (3.1 in). Its distinct characteristic is its large-diameter eyes. It is a common species in upland streams of the middle Mississippi River system. Bigeye shiners prefer warm, quiet pools with clear water and silt-free substrates. Siltation, channelization, and gravel dredging are all threats to bigeye shiner populations. During spawning season, typically late April to August, bigeye shiners have several clutches of eggs. State agencies and the EPA have both played a role in the surveying of bigeye shiner populations. Populations have decreased in Ohio due mostly to habitat destruction. In addition to habitat destruction by humans, habitat alteration of the small streams and dried pools has also had a significant effect on abundance. Rivers and streams should not be channelized or modified in any way, which is becoming an increasingly popular trend in urban locations. Agricultural areas and properties within the watershed should adhere to regulations to prevent runoff into the streams.
The blacktail redhorse is a species of ray-finned fish in the genus Moxostoma. The blacktail redhorse occupies North America, being located throughout Mississippi River tributaries on the former Mississippi Embayment, ranging from Southern Kentucky to Galveston Bay in Texas.
The scaly sand darter is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is endemic to the southeastern United States. It is found in the coastal plain area of the Mississippi River basin, typically in medium-sized streams with slow currents over sandy substrates where it feeds on midge larvae and other small invertebrates. The slender body is semi-translucent, yellowish with a dozen or so dark bars. This fish has a wide range and is relatively common, and the International Union for Conservation of Nature lists it as a "least-concern species".
The dusky darter is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is found in, but not confined to, both large and small rivers, and shallow creeks, in the eastern, southern, and southeastern United States, particularly the Mississippi River drainage system.
The holiday darter is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is found in the southeast US water system, with disjunctive populations throughout Alabama, Georgia, and Tennessee. It is also located in the Coosa River / Choccolocco Creek watershed which begins in Tennessee and far west Georgia, then enters Alabama. Its diet, close to other members of the subgenus Ulocentra, consists of small insects, including midges, black fly larvae, and small crustaceans. The two subspecies inhabit small to medium-sized gradient-rich streams. They are often found in fast-moving streams with large boulders, gravel, cobbles, and sand. They can be found in the margins between these large boulders, and use the boulders for protection from predators and for the females to attach eggs. The holiday darter has very vibrant coloration, but will display even more brilliant coloration during or before spawning. Spawning takes place during the spring, usually around April or May. This species is state listed in Georgia as threatened. One of the disjunct populations is located in the Talladega National Forest, which results in it being protected from human encroachment. The separate populations can make it difficult to determine the exact population count.
The blueside darter is usually found in the Tennessee River drainage in Tennessee, Alabama, North Carolina, and Virginia, and less commonly found in Bear Creek, Shoal Creek, and Barren Fork.
The cypress darter is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is endemic to fresh waters of the central and eastern United States. Its range includes drainages from the Choctawhatchee River, Florida, to the San Jacinto River, Texas, as well as the Mississippi River basin from southern Illinois and eastern Oklahoma to the Gulf of Mexico. It inhabits vegetated margins of swamps and lakes, and backwater habitats during the summer, while in winter it moves to flooded riffles and backwater bayous. It feeds mostly on small crustaceans, as well as insects and their larvae. Spawning takes place during spring and summer, with clusters of up to three eggs being laid, often stuck to the surface of dead leaves. The cypress darter has a very wide range and its population trend seems to be stable. It is a common species with numerous sub-populations, and the International Union for Conservation of Nature has assessed its conservation status as being of "least concern".
The gilt darter is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It can be found in a number of states in the Mississippi River drainage of the United States although it has been extirpated from some river systems in which it was at one time present, mostly due to siltation and pollution problems. Males are more colorful than females and can grow to a length of about 9 cm (3.5 in). It is a benthic fish that feeds primarily on small aquatic insect larvae. Males form territories during the breeding season in late spring and early summer. Spawning typically takes place at the upper ends of riffles with sandy and gravelly bottoms interspersed with larger cobbles. Some organisations are endeavouring to conserve populations of the gilt darter and re-introduce it to states where the fish has been extirpated but suitable habitat still exists.
The blackbanded darter is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is native to the river systems of the southeastern United States where it is found in the states of Tennessee, Georgia, Florida, Mississippi, Alabama, and Louisiana. It lives over sandy or gravelly bottoms in smaller rivers and streams and its color varies depending on the different habitats in which it lives. It feeds on small insect larvae and is itself preyed on by larger fish. It spawns between February and June depending on locality. It is generally a common fish throughout most of its range.
The saddleback darter is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is native to the eastern United States. This darter species is widespread, occurring from the Escambia River drainage west to the Mississippi River basin and as far north as the Wabash River historically. Some populations have been reported in the Tennessee River drainage. The saddleback darter is aptly named as it has 5 saddle-like patterns on its dorsum, with the first occurring near the first dorsal fin and the fifth near the caudal penduncle. Adults can attain a maximum size of about 3 inches or 7.8 centimeters. The saddleback darter typically occurs over sand and gravel runs of creeks and small to medium-sized rivers and is sometimes found in very shallow water. This darter's diet consists of invertebrates such as caddisfly larvae, beetles, mayflies, and stoneflies. The saddleback darter deposits eggs over sand and gravel shoals during the spring. This species has an average lifespan between 2 and 3 years.
The sickle darter is a recently identified freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is closely related to a well-known darter, Percina macrocephala. Discovered in 2007 in the upper Tennessee River drainage, the sickle darter is around 90.5 mm (3.56 in) in length and is a slender bodied, freshwater and benthopelagic fish that most likely feeds on small crayfish and mayflies, since it shares a large mouth and long snout with its sister species. The known distribution of the sickle darter is the upper drainage of the Tennessee River of Tennessee, North Carolina and Virginia. It is distinguished from all other Percina darters except its sister species P. macrocephala by a dark suborbital bar and a black bar subtending a medial black spot on the base of the caudal fin. It stays in mostly rocky, sandy, or silty substrates in clear creeks or small rivers in the Appalachian Mountains. The sickle darter spawns in late winter in gravel shoals. It also has large scales which make it different from macrocephala. It is known to be extirpated from most of its home habitat mainly because of agricultural practices that cause siltation and turbidity which causes most populations of the sickle darter to be widely scattered. But where it is found, it can be observed with regularity. Taking all this into consideration, the sickle darter does not have a formal conservation status under any federal or state law although its closely related species is considered a species of concern by the TWRA. Future management plans should include finding more locations of the sickle darter and decreasing further habitat destruction in known distributions by stating it as a fish of concern by state law.
Percina aurora, the pearl darter is a small species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. It is native to the United States, where it is known only from Louisiana and Mississippi, but seems no longer to be present in the Pearl River. Its total area of occupation is under 200 km2 (77 sq mi), it is a rare species and a candidate for federal protection. It is threatened by siltation, pollution, habitat destruction and urbanization, and as a result, the International Union for Conservation of Nature has classified its conservation status as being "endangered".