Endangered
Least chub
Iotichthys phlegethontis
Least chub is a minnow in the family Cyprinidae (order Cypriniformes) — Iotichthys phlegethontis, recorded as Endangered.
Appearance
Its lower sides and belly are golden, and they have yellowish fins. The dorsal fin contains 8-9 rays, with its origin just behind the pelvic fin insertion, and the caudal fin is slightly forked. There are 34-38 scales in the lateral series, and the lateral line is either absent or only features 1-3 pored scales.
It is the smallest of seven chubs native to Utah.
The least chub is a small fish, with a maximum size of less than 2.5 inches (64 mm).
Range and habitat
Historically, their range included Utah Lake, Provo River, Sevier River, streams, freshwater ponds, springs, and swamps near the Great Salt Lake. Least chub populations have declined in the 20th century due to the impacts of introduced non-native fishes. Consequently, they were found in 9 isolated spring pools in the desert regions of Utah.
Pins are Wikidata “endemic to” fields. Orange dots, when present, are GBIF occurrence tiles — survey bias included.
Breeding
Least chub spawn in the spring when the water temperatures reach 16 °C (61 °F). Least chub is an intermittent spawner, with females releasing a small number of eggs over extended periods, ranging from 300 to 2,700 eggs at a time.
The breeding season typically lasts from April to August, with peak activity in May, though it can extend longer depending on environmental conditions. Rather than temperature increases, spawning is triggered by changes in light.
In crisis
The least chub populations suffered a steep decline in the 1940s and 50s, though the decline wasn't noticed until the 70s. Studies indicate that where non-native fishes such as mosquitofish are introduced, few if any least chub remain. Conservation efforts for the least chub has also included the establishment of introduced populations as a key strategy to protect the species from habitat loss and other threats.
Introduced populations have proven to be successful due to the species' ability to adapt to various water quality conditions and rapid reproductive cycles. From 2014 onwards, ten stable populations were established in artificial ponds, providing a buffer against environmental threats such as drought and climate change.
Least chub is Endangered on this catalog because that is the IUCN category stored on Wikidata. Confirm the official criteria and any later count on iucnredlist.org.
Sources
Written for this catalog from the English Wikipedia article on Least chub, Wikidata item Q305792. Family and order context is original field-guide writing about the group, not a copied assessment of this one species. Wikipedia text is CC BY-SA. Not an IUCN assessment. Counts, when quoted, can change — confirm them on the recovery programme and on iucnredlist.org.
