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~- <( . Removal programs have become quite popular with management agencies and the present trend is generally toward removing large recreational predators. Hundreds of thousands of game fish have been removed. Unfortunately. th~r~ i8 little or no nata to suggest native communities have benefited. One of the purposes of targeting large predators is to reduce the reproductive capabilities. Unfortunately, there is growing evidence that while the abundance of large individuals has decreased, there has been a responding increase in smaller and intermediate-sized predators (Smith and Brooks 2000, Demers et al. 2001, Davis 2003). It appears standing crop has remained unchanged, but removal efforts have simply shifted size distribution of these populations. This response may actually create predation risks for small fish that are actually worse than no action at all. The. majority of native fishes are disappearing before they reach a few days old---at most a few weeks old---which suggests they are being lost by smaller predators rather than larger ones. Typically, large predators feed on large prey while small predators feed on small prey. The optimal foraging theory predicts that predators will choose prey sizes giving the highest energy return per time spent foraging. In simple terms, adult eagles don't waste time chasing flies. All evidence suggests that extremely young native fish are not being lost to the large predators. The increase of small predator densities may actually increase predation pressure, especially in nursery habitats. Small predators have better access to shallow and densely vegetated habitats and they also compete for food and space. It is possible small nonnative fish pose more of a predatory threat to early life stages than large predators (Nesler 2002). There is very little information available regarding the role of small nonnatives fishes. Ruppert et al. (1993) raised concerns about the role of adult red shiner on native larvae in the Yampa and Green Rivers. Unfortunately, the problem is not just limited to predatory fish. The detrimental aspect of bullfrog and nonnative crayfish introductions is currently being examined in amphibian restoration programs. These same problems appear evident for native fishes in CHLP. The objects of our test are two fold: 1) to determine the role of nonnative species (tadpoles and crayfish) in Cibola,. High Levee Pond, and 2) examine the role of small nonnative species in general, in the lower Colorado River mainstem. Methods Razorback sucker larvae and :fry were supplied by USFWS while nonnatives were provided by agency hatcheries, captured nearby, or purchased from aquaculturists. Tests were conducted in 10 and 30-gal tanks located at Willow Beach and Achii Hanyo Fish Hatcheries. 15