The study was designed to describe the phenotypic variations in morphometric and meristic characters of Clarias gariepinus between two populations in different towns in Ekiti State, Nigeria. Fish samples were collected from Ero dam (wild population at Ikun Ekiti) and Christeve Aquaculture (cultured population at Iyin Ekiti) using cast net and dragging net. The samples were brought to Zoology Laboratory in Ekiti State University and measurements for morphometrics (24) and meristics (11) of each of the investigated catfish specimen were taken using standard procedures. To test the significance of morphological differences between the wild and cultured populations, all the data on morphometrics and meristics were subjected to student's t-test at 5% level of significance. Principal Component Analyses and cluster analyses were then employed to analyse the data obtained from the morphological traits using Paleontological Statistics (PAST) software. Significant differences were observed in the means of the morphometric and meristic traits. The multivariate analysis also showed differences between the studied populations. These differences revealed the occurrence of heterogeneity between the two populations. Higher variations and sex related variations were also observed in the wild than in cultured population. The result show the potential for commercial purposes of the population. However, genetic markers can be used in further studies to confirm the phenotypic diversity observed and assess the amount of variation in these populations.
-Th e study determined the variation in the morphological and meristic features among four populations of Clarias gariepinus Burchell, 1822 obtained from Owena Dam and River Oluwa in Ondo State and Rivers Omo and Ogbere in Ogun State, both in Nigeria. A total of ninety fi ve (95) and one hundred and twenty (120) fi sh specimens collected from Ondo and Ogun states respectively were measured using standard procedures and the results were analysed using Analysis of variance and multivariate analyses. Th e results obtained from the ANOVA and Principal Component Analyses of Clarias gariepinus from the four populations revealed heterogeneity for most of their characters. Th erefore, the morphological diff erences between the wild African catfi sh found in Ondo and Ogun state populations could be linked to genetic diff erences or environmental factors or a combination of both factors. Hence, this study concluded that the populations are diff erent which could imply high genetic diversity if molecular marker techniques are employed in further studies.
Among other fish in Nigeria, Clarias gariepinus is mostly reared because of its good properties and these have encouraged farmers to invest in its seed production. However, most C. gariepinus farmers use brood-stock of unknown genetic quality and this practice has led to inbreeding resulting in the production of unviable hybrids which subsequently cause low productivity in fish farms. Research to increase the yield of C. gariepinus focused mainly on the food and feeding habits (
Morphological characterization of Sarotherodon galilaeus (Linnaeus, 1758)from Opa, Asejire and Ero reservoirs in southwest, Nigeria was carried out with a view to determining the morphological heterogeneity or homogeneity among the three different populations and to determine whether there are morphotypes of this species in the selected study areas. Twenty five morphometric measurements and six meristic counts were recorded on 150 specimens; fifty from each reservoir population. Principal Component Analysis (PCA) and Canonical Variate Analysis (CVA) were performed on the morphometric and meristic data using PAST software. All the clusters produced by the PCA and CVA analyses on the morphometric and meristic data overlapped widely; indicating a low level of morphological differentiation among the three populations of Sarotherodon galilaeus. The study concluded that the Sarotherodon galilaeus populations from Opa, Asejire and Ero reservoirs are morphologically similar and phenotypically inseparable.
Keywords: Morphometric, Meristic, Morphological differentiation, Reservoirs in south-western Nigeria, Sarotherodon galilaeus
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