Morphological variation between red mullet populations in Greece
ABSTRACT Morphometric variation in 15 characters of the red mullet Mullus barbatus samples from seven Greek localities was examined using multivariate analysis. ANOVA, stepwise discriminant analysis and cluster analysis revealed a rather high morphological variability between the populations studied. The discriminant analysis revealed that about 80% of the examined fish could be correctly classified into the seven areas. This variability could be explained in terms of genetic structuring of the populations and/or environmental conditions prevailing in each geographic area in combination with fish migration and egg/larvae transportation from one area to another. The results suggest that multivariate analysis when combined with other important biological parameters of red mullet may have important implications for the management of the Greek demersal fish resources.
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ABSTRACT: Population connectivity scales are important tools to achieve a mechanistic understanding of the factors regulating the abundance and distribution of marine populations and therefore support conservation actions to manage fisheries and stocks. We used 10 microsatellites markers on mullets' samples across the Spanish coast to determine the spatial scale of gene flow as well as the origin of post-larvae caught inside two MPAs. Population structure varied from complete homogeneity for Mullus barbatus, to high spatial variability in Mullus surmuletus samples. Differential habitat utilization by species, geomorphological features and oceanographic patterns are discussed as potential causes of patterns observed. Although we were unable to verify the origin of most post-larvae caught inside MPAs we suggest that they may act as genetic reservoirs due to high heterozigosity levels found in adult specimens inside (M. surmuletus) and nearby (both) them. Our results indicate that early life history traits (i.e. larvae) may not be the only determinant on species dispersal capability, suggesting that other mechanisms such as fine scale adult or juvenile movement may have been underestimated as promoting population connectivity.Marine environmental research 08/2013; · 2.34 Impact Factor
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ABSTRACT: The endangered Tor putitora is a commercially important freshwater cyprinid distributed widely in Himalayan foothills of India and adjacent countries. Despite its extensive distribution, the stock structure of the species is not known. The present study investigates intraspecific variations in wild and captive populations of this species using multivariate statistical tools. A total of 187 specimens were collected; 7 meristic and 25 morphometric characteristics were recorded for each specimen. The standardized data were subjected to a principal component analysis (PCA), discriminant function analysis (DFA) and univariate analysis of variance. Only 22 significant morphometric variables (P < 0.001) were considered for multivariate analysis. By applying PCA six principal components were generated explaining 88.71 % of total variance between the populations. The step-wise DFA retained only one variable showing highest variation in orbit diameter, maximum body depth, minimum body depth, head length, head depth, dorsal fin height and dorsal fin length, clearly discriminating the two populations. Using these variables, 84.5 % of the original groups were classified into their correct samples and 80.7 % of cross validated groups omitting one procedure were classified into their correct samples. The results obtained from this study have strong implications for sustainable management and conservation programme of the species.Proceedings of the National Academy of Sciences, India - Section B: Biological Sciences 07/2013;
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ABSTRACT: This study is based on the length-weight relationships (LWRs) of 2148 fishes, belonging to 8 families, 12 genera and 15 freshwater fish species (Wallago attu, Rita rita, Sperata seenghala, Sperata aor, Mastacembalus armatus, Macrognathus puncalus, Gudusia chapra, Clupisoma garua, Puntius sophore, P. ticto, Rasbora daniconius, Amblypharyngodon mola, Chanda nama, Colisa faciatus and C. sota) captured from river Ganga, Gomti and Rapti during May 2011 to March 2012. The growth coefficient (b) values varied between 1.30 and 3.07, with the mean b = 2.03 at p< 0.001. The condition factor (K) varied considerably from 0.76 and 2.95, with a mean K = 1.43 which may be attributed to different environmental conditions of the river basin. The objective was to evaluate the pattern of LWRs and condition factors of the freshwater fish species of the main Ganga and tributaries which serves as baseline for other tropical Indian rivers and tributaries.Journal of Environmental Biology 09/2013; 34(5):951-956. · 0.68 Impact Factor