Effect of Cadmium on the Developmental Instability of <i>Anabas </i><i>Testudineus</i> through Evaluation of Fluctuating Asymmetry of Its Bilateral Traits

Biomonitoring using fish has always been a popular method of assessing the toxic effects of cadmium on an organism. Increasing concentrations of cadmium in water bodies has led to bioaccumulation in the fish contributing to various morphological alterations. Among the known effects of these alterations is developmental instability via fluctuating asymmetry. Fluctuating asymmetry is increasingly being utilized as a simple yet effective method to evaluate the toxic effects of cadmium on the stability of development. This study used climbing perch (Anabas testudieneus) to assess the developmental instability caused by low level cadmium exposure by determining the fluctuating asymmetry in four bilateral traits; length of paired fins (pectoral and pelvic fins) diameter of eye and weight of gills. The left and right sides of the traits were measured once every four weeks for 16 weeks. The average measurements from both sides of the traits were used to calculate the FA value. Results found that the highest mean FA value in all traits except for pelvic fins were obtained in the highest treatment group, 0.015 mg/L. The increasing concentrations of cadmium exposure had a significant effect on the FA value of length of pectoral fins and diameter of eye but did not significantly influence the FA of weight of gills and FA of pelvic fin length. There was also a significant interaction between the duration of exposure and treatment groups in FA value of length of pectoral fin and diameter of eye, p < 0.05. The results from the study indicate that prolonged exposure to sub lethal concentrations of cadmium is able to cause significant effects on the normal development of length of pectoral fin and diameter of eye.