Overview
Ozark cavefish are small, blind fish that appear pink and white due to a lack of pigment, revealing their inner organs. They were listed as threatened in 1984 under the Endangered Species Act. Primary threats to the species are water contamination and depletion of the groundwater from farming, mining and urban development.
Scientific Name
Identification Numbers
Characteristics
Physical Characteristics
The head of Ozark cavefish are dorsoventrally flattened, with a slightly protruding lower jaw. The fish have no pelvic fins. The dorsal and anal fins are located more posterior than usual. The caudal fin is rounded and has two to three rows of sensory papillae on the upper and lower halves. The literature provides conflicting information on maximum length, but individuals of up to 65 millimeters were documented in surveys conducted at Logan Cave.
Ozark cavefish lack melanophores, a type of pigment cell that produces and stores melanin. As a result, these fish appear pinkish-white due to the visibility of their internal organs.
Habitat
Cavefish occur in groundwater habitats like the Springfield Plateau Aquifer, within Boone and Burlington Formation limestones. They also live in cave streams with chert rubble substrate, wells and sinkholes, and occasionally, in the soil phreatic zone.
Food
Cavefish diets are not well understood, but are believed to include small crayfish, isopods, copepods, ostracods, larval salamanders and young of their own.
Life Cycle
Geography
Ozark cavefish distribution is restricted to the Springfield Plateau geologic province of Arkansas, Missouri and Oklahoma. The Springfield Plateau encompasses approximately 21,000 square kilometers and drains the White, Neosho and Osage rivers. There have been 83 confirmed Ozark cavefish sites, plus at least 37 unconfirmed sites. However, between 1990 and 2019 Ozark cavefish were only detected at 41 sites in Arkansas, Missouri and Oklahoma. The 41 sites are distributed throughout 10 counties including Benton County in Arkansas; Greene, Jasper, Lawrence, Newton, Christian, Barry and Stone counties in Missouri; and Delaware and Ottawa Counties in Oklahoma. Arkansas has eight caves. Missouri has 25 caves and wells, and Oklahoma has eight caves. In addition, an eleventh site was confirmed at an upwelling in Washington County, Arkansas in 2020.
The Ozark Cavefish is a small 2-1/4 inch long, blind, pinkish-white fish. Due to the dark environments in which it resides, sight is unnecessary and the cavefish has no eyes.
Ozark Cavefish distribution is restricted to the Springfield plateau geologic province of Arkansas, Missouri, and Oklahoma. Ozark Cavefish historically occurred at approximately 52 sites (Brown and Todd, 1987). Graening et al. (2010) reported 83 confirmed sites, plus at least 37 unconfirmed sites. There are an estimated 41 active Ozark Cavefish caves and wells in Arkansas, Missouri, and Oklahoma.
Timeline
Explore the information available for this taxon's timeline. You can select an event on the timeline to view more information, or cycle through the content available in the carousel below.
8 Items