- Estimate seasonal survival rates of Flathead Chub, Platygobio gracilis through the lower section of Fountain Creek, Colorado.
- Quantify seasonal Flathead Chub movement through the study area.
- Examine mechanistic effects on these metrics, especially related to flow.
gear and field protocol recommendations for future studies by
quantifying detection probability of PIT tags using three gear types.
Dr. Kevin Bestgen, Larval Fish Laboratory, Colorado State University, and Dr. Larissa Bailey, Colorado State University
Effective conservation requires understanding the life history traits of the species of interest and mechanisms affecting those traits. Unfortunately, there is a lack of life history information—particularly quantified life history metrics—for many species. Quantifying life history metrics allows rigorous testing of mechanisms affecting species’ persistence, which can focus management efforts on the most effective actions for conservation. For this study, Flathead Chub in Fountain Creek were selected as the study organism and site for three reasons. First, compared to other plains stream fishes, Flathead Chub are relatively well studied, including a mark-recapture study in this study area. Second, for conservation purposes, it is important to determine the maximum amount of movement that fish within an assemblage will undertake. Therefore, it makes sense to select an active swimming species within a relatively long, unimpeded section of river. Flathead Chub in Fountain Creek fit this criterion. Third, Flathead Chub are relatively large-bodied compared to many other Great Plains fishes. This makes deploying PIT tags easier and reduces the effect of PIT tags on swimming performance (Figure 1).
Quantifying survival and movement allows testing of what is affecting those metrics. For apparent survival (ϕ), covariates being studied that may affect survival include multiple flow covariates, season, fish total length, and habitats associated with sites. Transition probability (ψ) covariates include high flow events, distance between sites, direction of movements, seasons, and fish total length. PIT tag detection occurred with three gear types: a 12-m mobile array; a 2-m mobile array; and scanning fish, collected via electrofishing, with an Oregon RFID handheld PIT tag reader (Figure 2). Using three gear types allows detection of fish in different habitat types. Ultimately, this study will help focus CPW staff to management actions that increase this fish’s survival rates and population persistence in Colorado.