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MORPHOMETRIC EVIDENCE FOR NUTRITIONAL STRESS IN ENGLISH SOLE
Power, J H. AND M. D. Weber. MORPHOMETRIC EVIDENCE FOR NUTRITIONAL STRESS IN ENGLISH SOLE. Presented at 2001 Estuarine Research Federation Meeting, St. Petersburg, FL, November 4-8, 2001.
We present an application of the powerful thin plate spline method of morphometric analysis to demonstrate its utility for detecting environmental stress in an estuarine flatfish. Juvenile English sole (Pleuronectes vetulus) were captured from Yaquina Bay, Oregon, photographed with 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 sole body were digitized from the images. The mean position of the landmarks of freshly caught sole were used to compute a reference specimen, and a thin-plate spline/relative warp analysis was done using all fish. Relative warp analysis of landmark data is analogous to principal component analysis, and yields relative warp scores. A discriminant function analysis of the sole's relative warp scores shows that fish held without food acquire different shape characteristics when compared to freshly caught fish, and that the shape differences reflect captivity and food deprivation. The technique may have applicability for detecting environmental stress in natural populations of estuarine fish.