Truss morphometric and meristic analysis of Nile tilapia (Oreochromis niloticus) strains from cultivation ponds in Samarinda City, Indonesia

Abstract

Abstract. Currently, many strains or varieties of Nile tilapia (Oreochromis niloticus Linnaeus, 1758) are kept by fish cultivators in Indonesia, such as red tilapia, white tilapia, black tilapia, and various hybrid crosses. These strains have been selectively bred or naturally occurring variants that exhibit different colors, patterns, growth rates, and other desirable traits. The large diversity of phenotypes in the form of strains in Nile tilapia opens opportunities to be utilized in breeding and aquaculture programs. However, the utilization of phenotypic diversity for breeding and cultivation purposes requires an introduction to the characteristics of these strains. The purpose of the study was to determine the morphological diversity between the varieties of Nile tilapia, including black tilapia, white tilapia, red tilapia, stocky tilapia, and larasati tilapia, from the collection and to estimate their relationships based on the level of diversity and similarity between populations. Morphological characterization was carried out using truss morphometric and meristic methods. Truss morphometric data were applied to principal component analysis (PCA), while meristic character data were analyzed descriptively by reviewing the literature. Kinship of five strains was tested by cluster analysis. The results of this study show that the character that strongly contributes to the differences in morphological shape in black and stocky tilapia are characters B1 (the distance from the front of the base of the ventral fin to front of the anal fin) and characters B3 (the distance from the front end of the base of dorsal fin rays to the front of the anal fin base), while the body shapes of red tilapia, white tilapia, and larasati tilapia tend to be more similar. Based on cluster analysis, it reveals that larasati tilapia, red tilapia, and white tilapia cluster into a single group, whereas stocky tilapia and black tilapia tend to form a distinct group. There are no significant differences between red tilapia, white tilapia, larasati tilapia, stocky tilapia, and black tilapia based on meristic characters.