Growth, Diet, and Fecundity of the Umatilla Dace in Northeastern Washington

The Umatilla Dace, a small cyprinid fish native to the Pacific Northwest was recognized by the American Fisheries Society in 2004. Here we present the first information ever recorded about the life history of the Umatilla Dace in Eastern Washington. Umatilla Dace (n=163 in 2013 and 13 in 2014) were collected respectively in the Colville River downstream of Meyers Falls and the Kettle River near Lauier, Washington. Scale samples (n=57), stomach samples (n=35) and egg skeins (n=15) were collected. Ages and total length (TL) at age was determined from scales using the direct proportion method. Average back calculated TL was 41mm (Age 1), 65mm (Age 2), 84 mm (Age 3) 100mm (Age 4), and 118 mm (age 5). Prey items were exclusively larval insects and included net spinning caddisflies (Trichoptera: Hydropshychidae), tube net caddisflies (Trichoptera: Psychomyiidae), and true flies (Diptera). Fecundity of 15 individuals ranged from 474 eggs for an 86 mm, 6 g female to 2,038 eggs for a 115 mm, 15g female. The TL/fecundity relationship was described by the formula Fecundity = 41.5 x TL - 3144.5 (R²=0.62). This information adds insight into a rare native fish in an area where research is geared almost exclusively to salmonids.