Landmark-based morphometric and meristic variations in populations of mullet, (Rhinomugil corsula) (Hamilton, 1822) in Bangladesh.

The landmark-based morphometric and meristic variations of three different stocks (the Meghna, Padma and Ichamoti) of Mullet (Rhinomugil corsula) were examined from a phenotypical point of view to evaluate the population structure and to assess shape variation. A total of 125 of Mullet (Rhinomugil corsula) were collected from three different water bodies: the Meghna, the Padma and the Ichamoti of Bangladesh during January to August 2013. Thirteen morphometric and seven meristic characters were analyzed along with twenty five truss network measurements. Eight (fork length, head length, pre-orbital length, post orbital length, highest body depth, lowest body depth, pelvic fin length and mouth gap) of 13 morphometric measurements, one (pectoral fin rays) of 7 meristic measurements and fourteen (1 to 2, 1 to 11, 1 to 12, 2 to 3, 2 to 12, 2 to 11, 2 to 9, 3 to 4, 3 to 11, 4 to 5, 4 to 7, 5 to 7, 7 to 8, 8 to 9) of 25 truss network measurements were significantly different (p<0.05 or p<0.01 or p<0.001) among three different populations of Rhinomugil corsula samples. For morphometric and landmark measurements, the first discriminant functions (DF) accounted for 89.8% and 83.3% and the second DF accounted for 10.2% and 16.7%, respectively of among group variability, explaining 100% of total among groups variability. For the morphometric and truss network measurements, plotting discriminant functions did not show the well separated clusters of the stocks. The dendrogram based on morphometric and landmark distances data showed two major clusters: the Meghna and the Padma stocks in one cluster and the Ichamoti stock in another cluster. High degree of variation was observed in morphological characteristics among three different stocks (the Meghna, Padma and Ichamoti) of Rhinomugil corsula due to their environmental variation and separate geographical location. These results of this study are very useful for proper conservation and successful aquaculture management of Rhinomugil corsula.