Date of Award


Degree Name

Biological Sciences


College of Science

Type of Degree


Document Type


First Advisor

Thomas K. Pauley

Second Advisor

David Mallory

Third Advisor

Elmer Price

Fourth Advisor

Jayme Waldron


The Northern Spring Salamander (Gyrinophilus porphyriticus) has a larval stage that could extend up to six years, an anomaly unheard of in other plethodontid salamanders. The size of a larva could be larger than an adult of a younger age. A sympatric species, Salvelinus fontinalis, the native brook trout, negatively alters the individual mass and survival of G. p. porphyriticus larvae. In the absence of trout, the role of G. porphyriticus ascends to top predator in a small stream community. Amphibians specifically have proven their role as stream indicators, a position attributed to their porous skin. I attempted to determine the correlation between larval duration and size in streams with or without brook trout, using Skeletochronology as a method for aging. Skeletochronology determined the age of individual salamanders using a cross-section of the femur. Age was determined by counting the lines of arrested growth. Basic methods of capture, measurement, and stream data collecting were implemented at four stream sites in western Pennsylvania from May 2012 to April 2013. Study sites include two streams populated by Salvelinus fontinalis and two with no trout with a total of 35 specimens. As expected, a standard growth curve (size vs. age) was found for larvae in streams containing Salvelinus fontinalis with a maximum age of 6 years. Larvae in fishless streams exhibited a non-standard growth curve specific to the individual stream attributed to climactic conditions, water quality, resource abundance, competition or other unknown reasons. The maximum age of larvae in fishless streams was 3 years, though all streams had similarly sized larvae. Growth curves between fish and fishless streams were significantly different (P = 0.001). Slow, consistent growth in the streams with trout was probably attributed to lower activity levels caused by risk of predation. Faster, less consistent growth in streams with no trout was probably due to intraspecific competition in addition to the absence of trout. The results of this thesis apply to a species of salamander with a broad range across the eastern United States, as well as the brook trout, an important game fish. My experiment examines the problem at the root, starting with a fundamental life history question of the Northern Spring Salamander.


Salamanders -- Ecology.