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
| Identifer | oai:union.ndltd.org:ORGSU/oai:ir.library.oregonstate.edu:1957/31820 |
| Date | 14 June 2002 |
| Creators | Weber, Madeleine Demaries |
| Contributors | Power, James H. |
| Source Sets | Oregon State University |
| Language | en_US |
| Detected Language | English |
| Type | Thesis/Dissertation |
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