Fish Springs NWR
Mountain Prairie Region

Brigham Young University personnel conduct Least Chub research at Fish Springs NWR      By Jill Ayala

 

   Picture of a hand with Utah chub   
Least chub
(lotichthyes phlegethontis)  were once widely distributed in the Bonneville Basin in a variety of habitats.  They now exist in only nine isolated spring pools in the west desert region of Utah.  Consequently, least chub are candidates for the federal list of endangered species, but conservation agreements by the state of Utah have forestalled this action pending future review of recovery status.
Currently, one of the major threats to remaining populations of least chub is the introduction of mosquito fish
(Gambusia affinis).  In Utah and elsewhere they have been widely introduced for mosquito control.  Once introduced, mosquito fish can rarely be eliminated from a site.  We can only attempt to control their harmful impact.

 

  Brigham Young University professors Dr. Russel Rade and Dr. Mark Belk (red hat) have designed studies to understand how least chub populations decline with mosquito fish.
Many of their studies have taken place at Walter Spring at Fish Springs NWR.

Samples fish being netted

 

Picture of fish researcher
In 2002, graduate students Mike Mills and Jill Ayala researched mosquito fish predation of least chub and least chub habitat selection in the presence and absence of mosquito fish.  Scientific findings will increase the chances of survival of this unique species endemic to Utah’s Bonneville Basin.

 

Picture of fish samples being taken in a boat
Water temperature, water depth and dissolved oxygen is recorded prior to pulling Fish Traps.
Picture of chubs in a bucket
After recording all data, fish traps are pulled and dumped into a bucket.
Picture of people counting fish
Samples from each trap are counted and documented.
Picture of Walter Spring study site Picture of lady pulling fish traps from water
Walter Spring research site Fish populations are sampled from multiple

sites every 4 hours day and night.

Last Updated November 15 2007
U S Fish and Wildlife Service