Date of Award

3-2022

Degree Type

Thesis

Degree Name

Master of Science

Department

Biology

Program

Biology (MS)

First Advisor/Chairperson

Dr. Jill B. K. Leonard

Abstract

The rapidly increasing temperatures of aquatic systems associated with climate change represent a novel threat to populations of brook trout (Salvelinus fontinalis), and much uncertainty remains about the potential of these populations to acclimate, adapt, or compensate for such changes. Brook trout are considered stenothermal, with a thermal preference of 14°C to 18°C, and a critical thermal maximum of 25°C. With such narrow thermal optima, brook trout are restricted to watersheds with adequate thermal refugia to withstand warm summer temperatures. For cold-adapted species such as brook trout (Salvelinus fontinalis), the long-term success of the species will depend on its ability to cope with, and adapt to, rapidly changing thermal conditions. The current study evaluated growth patterns of young-of-the-year brook trout in two tributaries with dramatically different annual thermal regimes. Using a common garden design, we then evaluated the effect of variable incubation temperatures on egg size, developmental phenology, yolk sac allocation, hatch timing, and size at hatch under laboratory conditions. The results of the current study provide evidence for plasticity in the developmental response of brook trout to withstand moderate effects of climate change. The results of the field studies demonstrated wide variability between populations, individuals, and cohorts. Laboratory studies suggested that population differences were largely mitigated by the effect of the environment, and that incubation conditions appeared to have a strong moderating effect on population differences in early development.

Access Type

Open Access

Justification for Restricting Access

Intended publication

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Available for download on Sunday, March 21, 2027

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