Lake Pleasant has historically been regarded as one of the premier largemouth bass (Micropteus salmoides) fisheries in Arizona. However, the quality of the largemouth bass fishery has decreased, resulting in low angler satisfaction and a general concern for the health of the fishery. The leading hypothesis for the cause of this decline is the recent invasion of striped bass (Morone saxatilis), which may be responsible, in part, for the shift in largemouth bass size structure through competition for resources and predation.

Apache trout is a federally threatened salmonid native to headwaters of the Little Colorado, Black, and White rivers in east-central Arizona. Decline of Apache trout to threatened status was attributed to over-fishing, habitat degradation and negative interactions (predation, competition and hybridization) with introduced nonnative salmonids. Although over-fishing is no longer considered a threat, habitat degradation and negative interactions with nonnative salmonids continue to threaten Apache trout, and it is towards these threats that recovery actions are directed. While barrier construction began in 1979 and livestock exclusion began in the mid-1980s, the efficacy of these recovery actions at increasing Apache trout abundance and improving habitat condition had not been evaluated. We therefore initiated a study to evaluate the efficacy of riparian fencing and barriers.