Reproduction by the Endangered Cui-ui in the Lower Truckee River

Abstract

Adult spawning behavior and emigration of larvae of the endangered cui‐ui Chasmistes cujus were studied in a natural side channel of the lower Truckee River. External radio‐tags placed on eight apparently did not affect spawning behavior. Cui‐uis spawned in clusters of two to seven fish; usually a single female was flanked by two males. Each spawning act lasted 3–6 seconds, and individual fish spawned numerous times. The most active tagged male and female spawned at least 294 times and 114 times, respectively. Individual females broadcast eggs over an area of up to 50 m2. Males spawned over a 4–5‐day period, and females over 2.5–4 days. Most spawning occurred at night in water depths ranging from 9 to 43 cm, water velocities ranging from 23 to 87 cm/second, and temperatures of 12–17 C. The preferred spawning substrate was gravel. Peak emergence and out‐migration of cui‐ui larvae occurred 14 days after peak spawning. Received September 7, 1982 Accepted August 5, 1983

Effect of four fluctuating temperature regimes on cui-ui,Chasmistes cujus, survival from egg fertilization to swim-up, and size of larvae produced

“…Prior to emigration they swim-up through as much as 10 cm of gravel (Scoppettone et al 1983). Large, robust larvae would presumably be better suited to this life-history pattern, where there seems to be substantial energy expenditure after swim-up, on reaching the lake, larger larvae would be in better condition to feed and escape predation than the smaller ones.…”

“…Cui-ui spawn in the Truckee River, Pyramid Lake's only perennial tributary (Scoppettone et al 1983). Each spring, adults migrate to the south end of Pyramid Lake; if flows and temperature are adequate, they enter the river to spawn, and females lay from 60000 to 195000 eggs (Scoppettone et al 1986).…”

Effects of Lake Surface Elevation on Shoreline‐Spawning Lost River Suckers

“…As is typical of western lake suckers, a Lost River Sucker spawning event lasts less than 6 s in which a single female is commonly flanked by two males (although up to seven males have been observed). Gametes are released over gravel substrate where water depth is typically between about 0.2 and 0.6 m (Scoppettone et al 1983;Sigler et al 1985;Perkins et al 2000b;Reiser et al 2001). Males often remain at the spawning area between spawning events whereas females often retreat to deeper water offshore, returning to spawn every few minutes (Perkins et al 2000b).…”

Battle against extinction: native fish management in the American West

“…Recent data from radio-tagged fish indicate that river migration encompassed less than 10 of the 19 km now available, and adults remain in the river for 4 to 16.5 days (Scoppettone et al 1986). Spawning occurs in relatively fast water (average 50 em S-I), at depths of 21-140 em on predominantly gravel substrates, and individual fish may spawn several hundred times in 3 to 5 days (Scoppettone et al 1983 Coleman et al 1987), and embryonic development is temperature dependent (Koch 1973). At diel water temperature fluctuations from I40to 17°C, eggs hatch in 10 days and larvae swim up after an additional 4 days (Coleman et al 1987).…”