College of Letters & Science

Permanent URI for this communityhttps://scholarworks.montana.edu/handle/1/37

The College of Letters and Science, the largest center for learning, teaching and research at Montana State University, offers students an excellent liberal arts and sciences education in nearly 50 majors, 25 minors and over 25 graduate degrees within the four areas of the humanities, natural sciences, mathematics and social sciences.

Browse

Filters

20221

Settings

Author: search.filters.author.Al‐Chokhachy, RobertSubject: search.filters.subject.phenology

Search Results

Now showing 1 - 1 of 1
  • Thumbnail Image
    Item
    The Importance of Phenology and Thermal Exposure to Early Life History Success of Nonnative Smallmouth Bass in the Yellowstone River
    (Wiley, 2022-07) Voss, Nicholas S.; Al‐Chokhachy, Robert; Sepulveda, Adam J.; Verhille, Christine E.; Ruggles, Michael P.; Zale, Alexander V.
    Knowledge of potential spread by introduced species is critical to effective management and conservation. The Smallmouth Bass Micropterus dolomieu is an example of a fish that has been introduced globally, often spreads after introduction, and has substantial predatory impacts on fish assemblages. Nonnative Smallmouth Bass in the free-flowing Yellowstone River, Montana, have expanded from warmer, downstream sections of river into colder, upstream sections containing socio-economically valuable trout fisheries. We sought insight into mechanisms controlling upstream spread by evaluating whether progressively colder upstream climates physiologically constrained successful recruitment by limiting age-0 growth and preventing overwinter survival (i.e., population establishment). We documented the phenology, growth, and overwinter survival of age-0 Smallmouth Bass across a temperature gradient leading to their upstream extent in the Yellowstone River. The upstream extent of population establishment did not appear limited by water temperature alone. Age-0 body size at the onset of winter did not differ significantly between colder, upstream reaches and warmer, downstream reaches. Instead, the earlier hatch timing exhibited by some age-0 individuals in upstream sections allowed them to experience longer growing seasons than many individuals in downstream sections. This counter-intuitive hatching phenology mediated much of the expected decreases in growth in colder, upstream climates. Furthermore, evidence of successful overwinter survival and simulations of age-0 starvation mortality indicated that age-0 individuals at the upstream extent of their distribution successfully recruited to the age-1 year-class during four consecutive years. However, age-0 individuals were rare or absent throughout the uppermost upstream distribution of adults, suggesting that something other than temperature limits or discourages reproduction farther upstream. Taken together, our results suggest that Smallmouth Bass have not yet reached the thermal limit of their upstream distribution in the Yellowstone River and that future spread may challenge fisheries managers tasked with management of coldwater trout fisheries in this river.
Copyright (c) 2002-2022, LYRASIS. All rights reserved.