Overview
Moapa dace is an endangered species endemic to Muddy (Moapa) River and associated thermal spring systems within the Warm Springs area of Clark County, Nevada.
Scientific Name
Identification Numbers
Characteristics
Food
Moapa dace occupy a variety of habitats in the Warm Springs area, including spring pools, tributaries (spring outflows), and the main stem Muddy River. Juveniles prefer tributaries and habitats with increasing flow velocities as they grow. Adults prefer both tributaries and the main stem Muddy River, with the largest adults occurring in the river.
The Moapa dace prefers habitat within local headwaters where water temperatures are between 82.4 to 89.6 degrees Fahrenheit and turbidity is low. It is known to occur in springs pools, spring feeders, small outflow streams, and the main river channel. A slight current exists in most areas inhabited by the species. Native waters for this unique fish are noted to be clear, with variable bottom types in pool habitats and may be spring deposited gravels or flocculent organic/silt. In outflow streams the bottoms may be of sand, gravel, pebbles and cobbles, or mud.
Habitat
Moapa dace occupy a variety of habitats in the Warm Springs area, including spring pools, tributaries (spring outflows), and the main stem Muddy River. Juveniles prefer tributaries and habitats with increasing flow velocities as they grow. Adults prefer both tributaries and the main stem Muddy River, with the largest adults occurring in the river.
The Moapa dace prefers habitat within local headwaters where water temperatures are between 82.4 to 89.6 degrees Fahrenheit and turbidity is low. It is known to occur in springs pools, spring feeders, small outflow streams, and the main river channel. A slight current exists in most areas inhabited by the species. Native waters for this unique fish are noted to be clear, with variable bottom types in pool habitats and may be spring deposited gravels or flocculent organic/silt. In outflow streams the bottoms may be of sand, gravel, pebbles and cobbles, or mud.
Life Cycle
Moapa dace apparently reproduce year-round, peaking in the spring. This species reproduces successfully in water temperatures ranging from 82.4 to 89.6 degrees Fahrenheit. The species matures at 1 year of age. Very little is known about the reproductive characteristics of the Moapa dace. However, redds believed to belong to Moapa dace were found approximately 150 m downstream from a spring orifice in sandy-silt substrate at depths of 15-19 cm.
Moapa dace can live for 4 or more years.
Physical Characteristics
Moapa dace can grow up to 4.7 inches long.
Geography
This species is endemic to Muddy (Moapa) River and associated thermal spring systems within the Warm Springs area of Clark County, Nevada. The Warm Springs area encompasses ten thermal spring provinces, which form the headwaters of the Muddy River. Moapa dace likely inhabited 25 springs and approximately 16 km of the upper Muddy River (Ono et al. 1983). Historically the Muddy River was 30 miles long, however in 1935, with the completion of the Hoover Dam, Lake Mead flooded the lower 8 km of the river, rendering it unsuitable for Moapa dace. Recent investigations found adult Moapa dace occurring in low numbers in restricted portions of 3 springs and less than 2 miles of spring outflow and river in the Warm Springs area (USFWS 1983).
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