2 resultados para Wavelet transform analysis

em Aquatic Commons


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The anatomical and morphometric (shape indices, contour descriptors and otolith weight) characterizations of sagittal otoliths were investigated in 13 species of Lutjanus spp. inhabiting the Persian Gulf. This is the first study that compares the efficiency of three different image analysis techniques for discriminating species based on the shape of the outer otolith contour, including elliptical Fourier descriptors (EFD), fast Fourier transform (FFT) and wavelet transform (WT). Sagittal otoliths of snappers are morphologically similar with some small specific variations. The use of otolith contour based on wavelets (WT) provided the best results in comparison with the two other methods based on Fourier descriptors, but only the combination of the all three methods (EFD, FFT and WT) was useful to obtain a robust classification of species. The species prediction improved when otolith weight was included. In relation to the shape indices, only the aspect ratio provided a clear grouping of species. Also, another study was carried on to test the possibility of application of shape analysis and comparing otolith contour of otoliths of Lutjanus johnii from Persian Gulf and Oman Sea to identify potential stocks. The results showed the otoliths have differences in contour shape and can be contribute to two different stocks.

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The Barotse floodplain is an ecosystem characterized by a paradox of widespread poverty amidst high ecological and agricultural potential. The CGIAR Research Program on Aquatic Agricultural Systems (AAS) seeks to address this paradox on the assumption that the rural poor have the potential to transform their lives using the aquatic resources in their environment. Understanding the conditions for natural resources use and management is critical for a program that seeks to transform the livelihoods of households dependent on natural resources. The purpose of this report is to identify and analyze key governance variables influencing the livelihood outcomes of AAS program interventions in the Barotse floodplain system.