Desert Sucker Catostomus clarkii and Sonora Sucker Catostomus insignis are two sucker species native to the Bill Williams and Gila River drainages in Arizona and New Mexico. Both species are considered Species of Greatest Conservation Need tier 2 species under the Arizona Wildlife Conservation Strategy. Despite their status, Desert and Sonora suckers are rarely the focus of dedicated conservation efforts and very little is known about their population status statewide. Knowledge of the demographics and status of fish stocks is critically important to effectively manage fish populations, either for angling, food harvest, or general conservation. The population demographics and status of various stocks of food fishes, popular sport fishes, and endangered fishes have been well. However, the status of many native fishes that do not fall into one of these categories have been little studied. This leaves stocks of particular native species, such as Desert and Sonora sucker at increased risk. In particular, Desert and Sonora suckers have recently begun receiving attention as a target for angling, from within and outside Arizona. Their populations in the Lower Salt and Verde rivers have been a particular focus of anglers. This increase in angling pressure is of concern to the AZGFD because they do not have any current information on the health and status of this population. Without this information the AZGFD is unable to evaluate how the increased angling pressure may affect the population and what conservation actions may need to be implemented to protect Desert and Sonora suckers in the Lower Salt and Verde rivers. Therefore, estimating the population demographics of these populations is necessary to effectively manage and conserve Desert and Sonora sucker in the Lower Salt and Verde rivers. Our goal is to provide information on the status of the Lower Salt and Verde River Sonora and Desert sucker populations. Specifically we are establishing the geographic extent of the populations of Lower Salt and Verde Desert and Sonora sucker, estimating the size of these populations, collecting demographic data on these populations including length at age, length and age frequency, survival, recruitment variability, age at maturity, and fecundity, and using this information in an established stock assessment model (e.g, FAMS) or Leslie matrix to identify the status of the stocks. We have just hired a graduate assistant for this project and are in the planning stages of the research.