Plagopterus argentissimus

Woundfin

Family: Cyprinidae · Class: Actinopterygii · Order: Cypriniformes

Conservation status: Endangered

The woundfin is a small, slender freshwater fish endemic to the Virgin River system. Adults typically measure 50 to 89 millimeters (2.0 to 3.5 inches) in total length, with a compressed body and pointed snout. The species exhibits a silvery coloration with a distinctive dark lateral stripe extending from the snout to the caudal peduncle. Males develop tubercles on the head and body during breeding season. The dorsal fin is positioned posteriorly on the body, and the species lacks scales on the posterior portion of the body, giving it its common name. Historically, woundfin occurred throughout the Virgin River system in Arizona, Nevada, and Utah. Currently, the species is found only in the Virgin River in southern Utah, Nevada, and northern Arizona, representing a significantly reduced range from historical distributions. The species has been extirpated from much of its former habitat due to habitat modification and water diversions. Woundfin inhabit flowing waters of the Virgin River system, preferring runs and quiet waters adjacent to riffles. Adults and juveniles utilize different microhabitats, with juveniles typically found in slower-moving waters with sandy or silty substrates. The species requires clear, flowing water with temperatures ranging from 18 to 30 degrees Celsius (64 to 86 degrees Fahrenheit). Stream flows and seasonal flooding patterns are critical for maintaining suitable spawning and nursery habitats. Woundfin are opportunistic feeders, consuming aquatic invertebrates including chironomid larvae, mayfly nymphs, and small crustaceans. Spawning occurs from March through July, with peak activity during spring runoff. Females deposit adhesive eggs in gravel substrates in shallow riffles. The species exhibits a relatively short lifespan, typically 2 to 3 years, with sexual maturity reached at approximately one year of age. Woundfin form schools and demonstrate strong site fidelity to preferred habitats. The woundfin was listed as endangered under the Endangered Species Conservation Act in 1970 and subsequently under the Endangered Species Act in 1973. Critical habitat was designated for the species in 1995. According to USFWS distribution data from 2023, approximately 7,077 individuals were distributed through conservation programs. Primary threats include habitat modification from water diversions, competition and predation from non-native fish species including red shiner and tilapia, and parasitic infections from the Asian fish tapeworm introduced by non-native species. The red shiner introduction may have facilitated tapeworm infestation of woundfin populations, contributing to population declines during the 1980s. Current recovery efforts focus on habitat restoration, non-native species removal, and captive propagation programs. Recent conservation initiatives include exploring translocation to expand the species' range within suitable habitats while maintaining genetic integrity of existing populations.

Data from The California Species Project — 14,000+ California species with verified data from CNPS, CDFW, USFWS, and more.