Length-Weight Relationship and Natural Diet of Hemichromis fasciatus, Coptodon zillii and Pelmatolapia mariae in Akomoje Water Reservoir, Abeokuta, Nigeria

Abstract

This study examined the length-weight relationship and natural diets of Coptodon zillii, Pelmatolapia mariae, and Hemichromis fasciatus in Akomoje Reservoir with aim of evaluating the length weight relationship and condition factors of the species, determine the sex ratio of the species and assessment of the stomach content of the species. Specimens were collected monthly between February and July 2024, then transported to the laboratory in ice chest where measurement of Total Length, Standard Length and Body weight started immediately to avoid shrinkage. Frequency of occurrence and numerical method were used for gut content analysis. Length-weight was analyzed using regression analysis. The study showed that combined sexes of Coptodon zilli from the study location exhibited isometric growth (b= 3) while Pelmatolapia mariae and Hemichromis fasicatus exhibited negative allometric growth (b = 2.7 and 2.5). The coefficient of correlation (r) values were for Coptodon zilli were positively weak (male: 0.055 and female: 0.265). For Pelmatolapia mariae the values positively weak (male: 0.348 and female: 0.412). For Hemichromis fasicatus the values positively strong for male weak for female (male: 0.662 and female: 0.290). In Coptodon zilli, the total of 11 categories of natural diet were unidentified in Akomoje Resevoir. Frequency of occurrence and Numerical method showed that Cyanobacteria, Diatom, Plankton and Green Algae were present. In Pelmatolapia mariae, the total of 13 categories of natural diet were unidentified in Akomoje Resevoir. Frequency of occurrence and Numerical method showed that Plankton, Cyanobacteria, Diatom, and Green Algae were present. In Hemichromis fasicatus, the total of 3 categories of natural diet were unidentified in Akomoje Resevoir. Frequency of occurrence and Numerical method showed that Cyanobacteria and Flagellates were present. The study revealed that male have better condition factor than females (with higher percentage in Pelmatolapia mariae and Hemichromis fasciatus) in this study location. Pelmatolapia mariae exhibited a positive allometric growth pattern, while Hemichromis fasciatus had a negative allometric growth pattern and there was a mixture between the two in Coptodon zillii.