Relations among arctic grayling, nonnative salmonids, and abiotic conditions in the Big Hole River, Montana
Arctic Grayling Thymallus arcticus in Montana have experienced declines in abundance and distribution over the last century, which contributed to the species being designated as a Species of Concern and petitioned for protection under the Endangered Species Act. Conservation of Arctic Grayling in th...
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ftmontanastateu:oai:scholarworks.montana.edu:1/14041 2023-05-15T14:31:16+02:00 Relations among arctic grayling, nonnative salmonids, and abiotic conditions in the Big Hole River, Montana McCullough, Austin Robert Chairperson, Graduate Committee: Christopher S. Guy Big Hole River (Mont.) 2017 application/pdf https://scholarworks.montana.edu/xmlui/handle/1/14041 en eng Montana State University - Bozeman, College of Letters & Science https://scholarworks.montana.edu/xmlui/handle/1/14041 Copyright 2017 by Austin Robert McCullough Arctic grayling Salmonidae Temperature Habitat (Ecology) Introduced fishes Thesis 2017 ftmontanastateu 2022-06-06T07:29:18Z Arctic Grayling Thymallus arcticus in Montana have experienced declines in abundance and distribution over the last century, which contributed to the species being designated as a Species of Concern and petitioned for protection under the Endangered Species Act. Conservation of Arctic Grayling in the Big Hole River watershed was based on presumed environmental influences. Interactions with nonnative species, increasing stream water temperatures, drought, and habitat alterations are suggested to influence Arctic Grayling abundances, although sparse quantitative information exists to support these hypotheses. My objective was to evaluate the influence of these biotic and abiotic factors on Arctic Grayling abundances using data collected in the Big Hole River drainage from 1983 through 2015. Arctic Grayling and nonnative salmonids were sampled at 32 sites, stream temperature data were collected at 33 sites, stream discharge data were collected at 21 sites, and habitat data were collected at 441 sites. Ordinary least squares and quantile (Tau = 0.90) regression analyses were used to evaluate the relationships among Arctic Grayling catch per unit effort (CPUE), nonnative salmonids CPUE, stream temperature, stream discharge, and habitat condition. The strongest univariate relationship was a positive correlation between the CPUE of Arctic Grayling > or = age 1 and Brook Trout Salvelinus fontinalis CPUE (r = 0.55, N = 77), which was contrary to the a priori predicted relationship. Multivariate analyses suggested that high water temperatures and low discharges during drought conditions have the greatest limiting influences on the CPUE of Arctic Grayling > or = age 1; Brown Trout CPUE, low water temperatures, and high maximum discharges were suggested as having the greatest limiting influences on age-0 Arctic Grayling CPUE. My findings support current management to increase discharge during drought conditions and further explore relationships between Arctic Grayling CPUE, habitat conditions, and Brown Trout CPUE. Thesis Arctic grayling Arctic Thymallus arcticus Montana State University (MSU): ScholarWorks Arctic |
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Open Polar |
collection |
Montana State University (MSU): ScholarWorks |
op_collection_id |
ftmontanastateu |
language |
English |
topic |
Arctic grayling Salmonidae Temperature Habitat (Ecology) Introduced fishes |
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Arctic grayling Salmonidae Temperature Habitat (Ecology) Introduced fishes McCullough, Austin Robert Relations among arctic grayling, nonnative salmonids, and abiotic conditions in the Big Hole River, Montana |
topic_facet |
Arctic grayling Salmonidae Temperature Habitat (Ecology) Introduced fishes |
description |
Arctic Grayling Thymallus arcticus in Montana have experienced declines in abundance and distribution over the last century, which contributed to the species being designated as a Species of Concern and petitioned for protection under the Endangered Species Act. Conservation of Arctic Grayling in the Big Hole River watershed was based on presumed environmental influences. Interactions with nonnative species, increasing stream water temperatures, drought, and habitat alterations are suggested to influence Arctic Grayling abundances, although sparse quantitative information exists to support these hypotheses. My objective was to evaluate the influence of these biotic and abiotic factors on Arctic Grayling abundances using data collected in the Big Hole River drainage from 1983 through 2015. Arctic Grayling and nonnative salmonids were sampled at 32 sites, stream temperature data were collected at 33 sites, stream discharge data were collected at 21 sites, and habitat data were collected at 441 sites. Ordinary least squares and quantile (Tau = 0.90) regression analyses were used to evaluate the relationships among Arctic Grayling catch per unit effort (CPUE), nonnative salmonids CPUE, stream temperature, stream discharge, and habitat condition. The strongest univariate relationship was a positive correlation between the CPUE of Arctic Grayling > or = age 1 and Brook Trout Salvelinus fontinalis CPUE (r = 0.55, N = 77), which was contrary to the a priori predicted relationship. Multivariate analyses suggested that high water temperatures and low discharges during drought conditions have the greatest limiting influences on the CPUE of Arctic Grayling > or = age 1; Brown Trout CPUE, low water temperatures, and high maximum discharges were suggested as having the greatest limiting influences on age-0 Arctic Grayling CPUE. My findings support current management to increase discharge during drought conditions and further explore relationships between Arctic Grayling CPUE, habitat conditions, and Brown Trout CPUE. |
author2 |
Chairperson, Graduate Committee: Christopher S. Guy |
format |
Thesis |
author |
McCullough, Austin Robert |
author_facet |
McCullough, Austin Robert |
author_sort |
McCullough, Austin Robert |
title |
Relations among arctic grayling, nonnative salmonids, and abiotic conditions in the Big Hole River, Montana |
title_short |
Relations among arctic grayling, nonnative salmonids, and abiotic conditions in the Big Hole River, Montana |
title_full |
Relations among arctic grayling, nonnative salmonids, and abiotic conditions in the Big Hole River, Montana |
title_fullStr |
Relations among arctic grayling, nonnative salmonids, and abiotic conditions in the Big Hole River, Montana |
title_full_unstemmed |
Relations among arctic grayling, nonnative salmonids, and abiotic conditions in the Big Hole River, Montana |
title_sort |
relations among arctic grayling, nonnative salmonids, and abiotic conditions in the big hole river, montana |
publisher |
Montana State University - Bozeman, College of Letters & Science |
publishDate |
2017 |
url |
https://scholarworks.montana.edu/xmlui/handle/1/14041 |
op_coverage |
Big Hole River (Mont.) |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic grayling Arctic Thymallus arcticus |
genre_facet |
Arctic grayling Arctic Thymallus arcticus |
op_relation |
https://scholarworks.montana.edu/xmlui/handle/1/14041 |
op_rights |
Copyright 2017 by Austin Robert McCullough |
_version_ |
1766304941853376512 |