Seasonal movements between mainstem and tributaries may facilitate the persistence of Roundtail Chub and Flannelmouth Sucker within an altered stream system
Objective Movement enables animals to complete their life history by responding to changing environmental conditions. Linking movement behaviors to life history characteristics can allow more targeted management applications for declining native fish populations. We identified seasonal movement patterns of Roundtail Chub Gila robusta and Flannelmouth Sucker Catostomus latipinnis , two understudied species that currently occupy only a portion of their historical range within the Colorado River Basin. Methods We coupled Passive Integrated Transponder tag antenna systems with multi-state capture-recapture models to quantify juvenile and adult movement between mainstem and tributary habitat within the Blacks Fork subbasin of southwest Wyoming, U.S.A. during 2019–2021. We also evaluated how flow and temperature may cue the timing of seasonal movements. Result Adults from both species made spring spawning movements to reach upstream tributary habitat, though adult Flannelmouth Sucker movements were more common and longer. Roundtail Chub primarily moved into the Hams Fork while Flannelmouth Sucker primarily moved into Muddy Creek, an intermittent tributary that was also identified as important for juvenile rearing. Juvenile movements occurred primarily during the fall months, with distance traveled comparable between species. Temperature and flow influenced the timing of spring spawning movements in adult Flannelmouth Sucker, with low flow potentially limiting access to preferred spawning habitat. Conclusion Identified movements likely contribute to Roundtail Chub and Flannelmouth Sucker persistence within this highly altered stream system and ultimately provide insights for management and recovery strategies to prevent further population declines.