The Moapa dace (Moapa coriacea), a tiny fish that was placed on the U.S. Endangered Species List in 1967 has experienced a boom in its population numbers in the three springs in Nevada where the fish can be found. Recent government counts put the population of Moapa coriacea at 1,181, up from 473 in 2007.
According to a report in Scientific American, the increase occurred in the last year and is close to coming to pre-2007 population levels. That is the good news. The bad news is the population of Moapa dace needs to increase by close to 5,000 individual fish in order for it to be considered recovered and removed from the Endangered Species List.
The U.S. Fish and Wildlife Service have worked over the years to restore the habitat of this fish. In addition to restoring sections of streams, the agency has eliminated invasive species that eat the Moapa dace, including mollies (introduced into the river in 1963) and tilapia, which were found in the river in the 1990s. Both of these invasive species eat the Moapa dace as well as the food of the tiny fish.
The report also says that proposed groundwater developments could reduce the habitat of the Moapa dace. Another element that could contribute to the decline of the fish is wildfires. A wildfire in 1994 killed about half of the population of Moapa dace, the report said.
The fish grows to just 9 centimeters in length and requires a water temperature of 86.9 degrees Fahrenheit to survive. It is currently found in just three springs along a 1.8 mile stretch of Nevada’s Muddy River.