Predation by Age-0 Smallmouth Bass (Micropterus Dolomieu) on Bigscale Logperch (Percina Macrolepida) in the Pecos River, New Mexico (Notes) (Report‪)‬

Nonnative species of fish preying upon native species has been documented widely in North America, particularly in the desert Southwest (Meffe, 1985; Ruppert et al., 1993; Marsh and Douglas, 1997; Brandenburg and Gido, 1999; Knapp and Matthews, 2000; Robertson and Winemiller, 2001; Pilger et al., 2008). Nonnative species might be responsible for declines in native species and hinder recovery efforts (Marsh and Brooks, 1989; Minckley, 1991; Scoppettone, 1993; Whittier et al., 1997; Whittier and Kincaid, 1999). Micropterus appears to have the largest effect on species richness of native species in lakes in northeastern North America (Whittier and Kincaid, 1999) and might be responsible for regional declines in native minnows (Whittier et al., 1997). The effect of smallmouth bass (M. dolomieu) on native fishes in New Mexico is unknown; however, fish constituted 32.5% of food items in smallmouth bass examined in the Devil's River, Texas (Robertson and Winemiller, 2001). The native manantial roundnose minnow (Dionda argentosa) had the highest electivity index of all fish preyed upon by smallmouth bass in that study, suggesting that smallmouth bass select D. argentosa. Smallmouth bass are nonnative predators present in the Pecos River system of New Mexico. Smallmouth bass have been documented to switch to piscivory at age-0, total length 40-100 mm (Scott and Crossman, 1979), with fish contributing 10-40% of the total diet when first becoming piscivorous (Scott and Crossman, 1979; Probst et al., 1984). Analysis of gastrointestinal contents of largemouth bass (M. salmoides), revealed 87% of fish consumed were native cyprinids and catastomids, despite nonnative species comprising 80% of the potential prey base (Pilger et al., 2008). Smallmouth bass in the lower Yakima River, Washington, preyed on Chinook salmon (Onchorhynchus tshawytscha) that were a maximum of 56.6% of the length of the predator and averaged 25% of the length of the predator (Fritts and Pearsons, 2006).