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|Title: ||Morphometric, meristic and allozyme studies of black- chinned tilapia, sarotherodon melanotheron melanotheron (ruppell, 1852) (pisces: cichlidae), populations in coastal waters of Ghana|
|Authors: ||Quarcoopome, Theodore|
|Issue Date: ||5-Feb-2000|
|Series/Report no.: ||2903;|
|Abstract: ||The black-chinned tilapia, Sarotherodon melanotheron melanotheron, (Ruppell, 1852) is widely distributed and of socio-economic importance in Ghana but not much is known about the morphological and genetic variation within its natural populations in coastal waters. This study was aimed at determining the characteristics, variation and relationships among populations of S. m. melanotheron in coastal waters of Ghana based on morphometric, meristic and allozyme data. In all, 238 individual specimens were sampled from nine (9) lagoons across the entire coastline of Ghana for the study.
Morphological screening of individual morphological characters indicated significant differences in their means among seven populations studied. Specimens from Ankobra lagoon showed the least intrapopulation variation, especially for morphometric characters while specimens from Hwin lagoon showed the greatest variation. For meristic characters, specimens from Hwin lagoon showed the least intrapopulation variation while the Fosu population recorded the highest. For each morphological character, homogeneous groups of populations within which no significant differences occurred as well as pairs of populations that differed significantly in their means were identified and these indicated moderate interpopulation variation for the subspecies. The most substantial differences in interpopulaton variation for individual characters was made by the Abbey population. For body proportion variables, significant differences in means were observed; however, no single population made the most significant contribution to variation observed. Total lateral line scale count range of 26 to 30 was observed in this study as against that of 27 to 30 by other workers, thus requiring its revision.
Allozyme analysis based on data from standard horizontal starch gel electrophoresis showed that all nine S. m. melanotheron populations possessed identical alleles at all 13 loci screened. Of all loci screened, only MDH-3 was polymorphic thus giving mean low percentage polymorphic loci of 7.7% and mean heterozygosity of 0.040. Analysis of unbiased genetic distance and genetic identity by the method of Nei (1978) gave 0.0 and 1.0 respectively for all populations. Observations at each polymorphic locus in all populations showed deviations from Hardy-Weinberg equilibrium. The results suggest that the nine S. m. melanotheron populations have little genetic diversity and are genetically identical and form a homogenous group with no subdivisions.|
|Description: ||A thesis submitted to the Board of Postgraduate Studies, Kwame Nkrumah University of Science and Technology, Kumasi, in partial fulfilment of the requirement for the award of Master of Philosophy Degree in Biological Sciences, 2000|
|Appears in Collections:||College of Agric and Natural Resources|
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