This thesis focuses upon whether stressful aspects of an organism's environment are reflected by that organism's shape. It presents an application of the powerful thin-plate spline and relative warp methods from morphometric analysis to demonstrate the overall utility of morphometrics in detecting environmental stress in an estuarine flatfish, the English sole or Pleuronectes vetulus. Juvenile English sole were captured from the Yaquina Bay, Oregon, photographed using a digital camera, and then held without food in the laboratory for periods of 7 to 24 days. Landmarks on the outline of the ventral surface of the body were digitized from the images. The mean position of the landmarks for freshly caught sole was used to compute a reference specimen. The thin-plate spline method was then applied to quantify the intraindividual shape variation due to lab-induced environmental stressors for all fish. Relative warp analysis of the resulting landmark data yielded relative warp scores for each individual fish, and was analogous to a principal component analysis. Analysis of covariance of the relative warp (principal component) scores showed that fish held without food acquire different shape characteristics in comparison with freshly caught fish, and that these shape differences reflect captivity and food deprivation effects. A discriminant function analysis using the data allows clear differentiation of stressed and non-stressed fish. The underlying goal of this research was to examine the conceptual and methodological aspects of morphometrics relevant to its future potential use as a measure of developmental precision and environmental condition. The technique may have applicability for detecting environmental stress in natural populations of estuarine fish. / Graduation date: 2003