Due to habitat degradation and introduction of non-native fishes, it is currently limited to a few spring complexes in Utah and the Snake River Valley in Idaho.

[10] In 2021, new populations of least chub were documented in Idaho’s Snake River drainage, suggesting the species’ potential range could be larger than previously thought.

In 2013, a significant drop in groundwater caused most of the surface water to disappear, leaving fewer places for fish to live and breed.

These reproductive adaptations, including extended spawning periods and tolerance to fluctuating water conditions, allow the least chub to thrive in the variable environments of spring and marsh complexes.

Reasons for the decline include habitat destruction from cattle grazing on and trampling streamside vegetation, water diversion, mineral and energy development, and non-native fishes.

Other conservation efforts include working with ranchers to fence off critical spring complexes to prevent habitat destruction from cattle grazing.

Recently the Utah Division of Wildlife Resources teamed up with mosquito abatement districts in Davis and Salt Lake counties to distribute the fish to 240 backyard ponds to evaluate it as a potential mosquitofish replacement.

[17] 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.

Conservationists continue to monitor both natural and introduced populations to ensure long-term survival, particularly in the face of climate change and groundwater depletion.