Comparative study of morphometric characters of diploid and triploid juvenile catfish, <I>Clarias gariepinus</I>

Abstract

The study was conducted to compare morphometric variables of diploid and triploid Clarias gariepinus. A total of 17 morphometric characters were measured. Five length classes of 10 samples each for each strain was chosen thus: Class1 (7.5cm - 10.4cm), Class2 (10.5cm - 13.4cm), Class3 (13.5cm – 16.4cm) Class4 (16.5 cm - 19.4cm), and Class5 (19.5cm - 22.4cm). Data collected were subjected to statistical analysis for significance at 5% probability level using descriptive statistics. Results revealed that measurements showed linear correlation between fish length and size in both strains. When the diploid and triploid groups were compared it was observed that body characters (85.6% of total characters) were higher in triploid than diploid fishes. However, head characters were observed to be higher in diploid than triploid. For instance, in Class1, diploid fish had higher values for barbel length (diploid 3.08cm; triploid 3.0cm), pre-pectoral fin length (diploid 2.05cm; triploid 1.99cm) and pre-maxillary width (diploid 0.97cm; triploid 0.91). A similar trend was observed in all other length classes. There were no significant differences (p > 0.05) in morphometric characters relating to body measurements. This considered the triploid fish to be closely related to the diploid group which can be confirmed by the study of genetic characters.

Key Words: Morphometric characters, Diploid, Triploid, Juveniles, Clarias gariepinus