Fundulus julisia | Barrens Topminnow
The Barrens Topminnow was the subject of Pat Rakes' thesis (1989) at the University of Tennessee. Restricted to only a few localities on the Barrens Plateau in Cannon, Coffee, and Warren counties, Tennessee, the Barrens Topminnow inhabits clear, spring-fed streams and relies on aquatic vegetation for spawning. Only three small original populations remain in the wild. The species is constantly threatened by habitat destruction and drought as well as an introduced non-native species, the western mosquitofish, which out-competes and eliminates the topminnow nearly everywhere they make contact.
The Barrens Topminnow is considered endangered by the state of Tennessee, but enjoys no Federal protection status. In most years in the past decade, the "type locality" for the species, a small spring pond whose Barrens Topminnows were used to formally describe the species in 1982, has nearly or completely dried up, leaving small numbers of individual fish to be "rescued" by both CFI and the Tennessee Aquarium to house over winter and return the following spring. An unforeseen benefit of the spring completely drying up was the elimination of mosquitofish, followed by exclusion by a barrier, but clearly this is a population that requires constant close monitoring.
CFI has been maintaining arks and actively propagating three separate (genetically distinct) populations of Barrens Topminnows since the mid-1980s. Numerous reintroduction efforts are currently underway on the Barrens Plateau with nearly 20 population restoration sites. Active monitoring and studies at these sites are conducted by Tennessee Tech University graduate students. Unfortunately, suitable reintroduction sites not already infested with mosquitofish are rare.
In 2020 the Barrens Topminnow were added to the Federal Listing as Endangered.