Studies of fish report that heavy metals and pesticides can alter metallothionein (MT) expression, and acetylcholinesterase (AChE), lactate dehydrogenase (LDH), and glutathione-s-transferase (GST) activities in a dose dependent manner. Thus, these proteins serve as indicators of contaminant induced alterations in physiological function. In this study, trout were collected from two sites in the Owhyee mountains. Fitness index, stomach content richness as well as the physiological biomarkers gill MT expression and brain AChE, tail muscle LDH, and liver GST activities were measured to determine whether differences in fitness and physiology of trout populations existed between the two sites. Jordan Creek served as our contaminated site as trout inhabiting this watershed exhibit elevated mercury concentrations. A site on the North Fork Owhyee River served as our reference population. We hypothesized that trout inhabiting Jordan Creek would exhibit reduced fitness and stomach content richness and increased MT levels as well as increased LDH and GST activities. We also anticipated disruption of AChE activity for Jordan Creek trout. Our results suggest that contaminants in the Jordan Creek watershed are eliciting biological responses in local trout populations. Further study is needed to characterize the extent and type of contamination present in these sites.

COMPARISON OF BIOMARKERS IN REDBAND TROUT (Oncorhynchus mykiss gairdeni) BETWEEN NORTH FORK OWYHEE RIVER AND JORDAN CREEK, SOUTHWESTERN IDAHO REVEALS PHYSIOLOGICAL DIFFERENCES SUGGESTIVE OF CONTAMINATION