Does fish scale morphology allow the identification of populations at a local scale? A case study for rostrum dace Leuciscus leuciscus burdigalensis in River Viaur (SW France)

Abstract.

The aim of the study was to investigate if scale morphology could be used to discriminate fish populations at a local scale. To this aim, 168 rostrum dace (Leuciscus leuciscus burdigalensis) were collected at 3 sites in the River Viaur (SW France), distributed along 82 Km of stream. Seventy-one measurements were taken from scales: 2 shape factors and 69 Fourier coefficients. A stepwise discriminant analysis revealed that fish from the 3 sites showed morphological differences (p < 0.001), with an average of 75.6% correct discrimination of the scales (65.5% after the cross-validation procedure). These results reveal that scale morphology can detect spatial structure in fish populations at a fine scale, which has implications for riverine fish conservation.