Product diversification, among which organic farming, is an important issue in modern aquaculture activities. Discriminating organic vs. conventional products is complex, but appearance may help in tracing different batches of produce. To test this fact, sea basses were fed a commercial or an organic diet, and fishes of each different group were photographed before and during the experiment. Body landmarks were digitized on each colour-calibrated (using the TPS-3D algorithm) image; on the basis of landmarks configuration, the RGB matrices were warped using a geometric morphometrics procedure. The calibrated colour matrix of each warped individual (195 × 135,225) was analyzed with a 50–50 MANOVA, followed by a partial least squares discriminant analysis. Finally, a cluster analysis on the diet/time groups was performed. Growth and changes in condition factor over time are not dependent on the rearing method. Colour (as represented by the pixel vector) does depend on time and on rearing method, based on the MANOVA method used. Standard length and condition factor were not good predictors of colour. The partial least square discriminant analysis was highly effective in detecting colour differences on the basis of the fish diet. The 9-group dendrogram showed that the wild sample and the organic fish cluster together. The head, darker in fishes raised conventionally, is the part showing the greatest difference; the longer the life spent under the 2 regimens, the stronger the differences. In conclusion, these preliminary results demonstrate that a colorimetric analysis is able to distinguish 2 batches of fishes fed different diets in different environmental conditions and – in the present instance – to certify the organically grown sea basses. 相似文献
Difficulties in the accurate identification of the Phytophthora species responsible for black pod disease of cocoa continue to hamper effective disease control. A re-evaluation of morphological characters ( Brasier & Griffin, 1979 ) and a detailed morphometric analysis of 161 Phytophthora isolates largely associated with black pod disease of cocoa from 17 countries worldwide have shown considerable inter- and intraspecific variation. Stable and more reliable parameters for the identification of the species responsible for the disease have been determined. Colony characteristics such as pattern and growth rate on V8 agar are reasonably characteristic for the cocoa Phytophthora species, and can be used to make preliminary identification to species level. Significant sporangial character variation was found within isolates of species from the same and different sources, highlighting the difficulties in making accurate identification on the basis of raw morphological data. Pedicel length was found to be the most consistent species-linked sporangial characteristic. Cluster plots of length/breadth ratios of sporangia versus reciprocals of sporangial pedicel length clearly separated all isolates into distinct species groups ( P. capsici , P. citrophthora , P. palmivora and P. megakarya ) and can be used reliably to identify accurately those pathogens involved in black pod disease outbreaks. 相似文献