UVM Theses and Dissertations
Format:
Print
Author:
Butryn, Ryan S.
Dept./Program:
Natural Resources
Year:
2010
Degree:
MS
Abstract:
Water temperature plays a dominant role in the distribution of fish species within a river, especially in native coldwater fish such as brook trout (Salvelinusfontinalis). Unsuitable temperatures caused by anthropogenic disturbances and climate changes can have a negative effect on brook trout distribution. Better understanding of where and how temperature limits the success of brook trout is needed to identify and set targets for conservation efforts as well as track changes in distribution in response to climate change. We approached this research in three ways. First, we evaluated the spatial and temporal variability in stream temperature using numerous temperature loggers, which documented that: 1) a single logger represents temperature of a typical 150-300 m fish study reach, and 2) longitudinal change in temperature was variable at a scale of ~ 1 km. Next, we used a long-term fish and temperature dataset from the Dog River in central Vermont to determine the relationship between sublethal temperature stress metrics and the downstream extent of brook trout distribution.
Duration and average magnitude of temperature events>22°C were associated with changes in the proportion of brook trout in relation to other trout species. Predictions of brook trout distribution categories with temperature metrics in a canonical discriminant classification analysis were accurate 74% of the time. Last, we analyzed stream temperature over the past 10 years at 207 locations, which represented about 40% of Vermont streams. We summarized the sublethal temperature stress and climate conditions for each summer. Analyses of the annual variability in sublethal stress event frequency, duration, and magnitude in response to variability in summer climate indicated that the frequency of temperature events was related to summer air temperature (R² = 0.85). This relationship provides a method of tracking thermal stress to brook trout given impending climate change. Results from this research will allow fisheries managers to assess coldwater habitat suitability when only temperature data are available and can guide decision making for the conservation of native salmonid conservation.
Duration and average magnitude of temperature events>22°C were associated with changes in the proportion of brook trout in relation to other trout species. Predictions of brook trout distribution categories with temperature metrics in a canonical discriminant classification analysis were accurate 74% of the time. Last, we analyzed stream temperature over the past 10 years at 207 locations, which represented about 40% of Vermont streams. We summarized the sublethal temperature stress and climate conditions for each summer. Analyses of the annual variability in sublethal stress event frequency, duration, and magnitude in response to variability in summer climate indicated that the frequency of temperature events was related to summer air temperature (R² = 0.85). This relationship provides a method of tracking thermal stress to brook trout given impending climate change. Results from this research will allow fisheries managers to assess coldwater habitat suitability when only temperature data are available and can guide decision making for the conservation of native salmonid conservation.