The Woundfin (Plagopterus argentissimus) is a species of minnow endemic to the Virgin River of the southwestern United States. It is a slender, silvery minnow, with a flattened head and belly, long snout, leathery skin, and no scales. There are barbels on the corners of its lips, and its common name likely comes from the first spinous ray of its dorsal fin, which is sharp-pointed. Its maximum length is rarely more than 3 in (7.5 cm). Historically, the Woundfin occupied much of the lower Colorado River basin, including two tributaries, the Virgin River and part of the Gila River; however, habitat destruction through dams and water development has led to its extirpation from these regions. In addition, several introduced species, most notably the red shiner (Cyprinella lutrensis) have contributed to a decrease in the Woundfin’s Virgin River population. The Woundfin is currently federally listed as an endangered species, while the United States Fish and Wildlife Service lists the population status as “declining.”
The Woundfin is the only species of its genus, Plagopterus. This genus belongs to the Cyprinid tribe Plagopterini, of the subfamily Leuciscinae. Plagopterini also contains the monotypic genus Meda (the spikedace, Meda fulgida) and the genus Lepidomeda, which contains four species. All six species are endemic to the lower Colorado River basin, with the Woundfin and Spikedace being the most closely related.
The scientific name Plagopterus is Greek for “oblique wing” (plagios, “oblique”, and pteron, “wing”). Argentissimus is Latin for “most silver” (argentus, “silver-colored” + issimus, superlative suffix).
Distribution and habitat
The Woundfin tolerates highly mineralized, turbid waters. It is typically found in warm, swift streams of high turbidity, preferring a stream speed of one to two feet per second and a depth of eight to eighteen inches.
The Woundfin is omnivorous, and depending on availability will feed on detritus, algae, seeds, and aquatic insects and their larvae.
Historically, the Woundfin also occupied the lower Colorado River from the Virgin to Yuma, Arizona, and the Gila River from Yuma to its confluence with the Salt River. Habitat destruction through water development (including eight major dams which alter flow) and the introduction of several species (particularly the red shiner (Cyprinella lutrensis), which compete for food and is known to prey upon the Woundfin’s eggs and young) have led to its extirpation in these regions as well as a decline in population in the Virgin River. Since 1970, the Woundfin has been listed as an endangered species. Other listings include “Vulnerable” on the IUCN Red List and “Critically Imperiled” (the most critical classification) by NatureServe. The United States Fish and Wildlife Service lists the population status as “declining.”
The Dexter National Fish Hatchery in Dexter, New Mexico studies the Woundfin in an effort to help conserve the species, and has successfully spawned the fish in captivity. However, efforts to transplant the species into other rivers and creeks have failed due to reproduction not taking place.
Another minnow, the Virgin River chub (Gila seminuda), has much of the same range as the Woundfin and thus faces the same threats of extinction, particularly competition from the red shiner and a decrease in water quality as the result of agricultural runoff.
Photo Â© 2005 John White