If agencies are concerned about abundance of Prairie Chub, then management agencies may want to consider the strong relationship with salinity when desalinization projects are proposed. We show substantial variation in spawning patterns among rivers that has important implications for developing conservation actions. Our results indicate conservation of Prairie Chub and ecologically similar species would benefit from maintaining broadly connected habitats (i.e., for movement and drift). Our juvenile Prairie Chub abundance model had similar but weaker relationships with covariates compared to the adults however, juvenile abundance was higher in 2020 compared to 2019. Adult Prairie Chub abundance had a quadratic relationship with salinity where Prairie Chub density peaked at a salinity of 10 ppt and then declined by nearly 100% when salinities reached 20 ppt. Overall, adult Prairie Chub abundance was higher in the eastern portion of their range and increased with increasing discharge and turbidity but decreased at higher water temperatures. ![]() We found Prairie Chub abundance was related to several covariates, but abundance did not vary much between years. Our abundance estimates were consistently lower in upstream reaches, higher in downstream reaches, and more variable in mid reaches. We conducted 104 abundance surveys in 20. The number of successful hatches observed per spawning day was highest in the Pease and Red rivers and lowest in the Salt Fork and South Wichita rivers for both years. Spawning was more likely to occur earlier in the sample season though substantial spatial and temporal variation in spawning success was evident among rivers. The probability of spawning increased with increasing scaled discharge and average temperature in both 20. The likelihood of spawning and frequency of observed hatches per spawning date were higher in 2019 compared to 2020. We processed otoliths for 2,017 age-0 Prairie Chub across 7 rivers and two spawning seasons (i.e., 20). ![]() We found no evidence of upstream bias in adult Prairie Chub movement during our study. The average expected movement distance of the stationary population component was 2 m in 2019 and 3 m in 2020, whereas the expected average movement distance for the mobile population component was 42 m in 2019 and 75 m in 2020. Movement by Prairie Chub was consistently greater than expected under the restricted movement paradigm. We conducted recapture events at approximately 2-week intervals from late May to August of 20. ![]() We tagged 5,771 Prairie Chub during summers of 20 and recaptured 213 fish across both summers. We assessed Prairie Chub movement using a mark-recapture experiment with multiple tag and recapture occasions during late spring through summer (i.e., May-August) of 20. Our study objectives were to evaluate Prairie Chub movement, identify spawn timing, and estimate abundance of Prairie Chub at locations in the upper Red River basin. ![]() Hypothesized mechanisms have been proposed to explain the decline of pelagic broadcast spawning minnows including disrupted spawning cues, reduced recruitment, degraded habitat complexity, and reduced water availability and connectivity. The Prairie Chub Macrhybopsis australis is a poorly studied endemic cyprinid of the upper Red River basin and is listed as threatened in Texas and of greatest conservation need in Oklahoma.
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