Evaluation of the Ecological Potential of Fish Production Ponds in the Eastern Region of Cameroon

10 June, 2026

Background and Objective: Fish production in both soilless and ponds remains low in Cameroon. To improve the capacity of pond fish farming systems to produce competitive marketable fish in sufficient quantity, ecological indicators of the productivity of fish farming practices were assessed in 16 dam ponds from January to December, 2021 in the Eastern Region of Cameroon. Materials and Methods: The 4 fish farming practices, namely, unfertilized pond culture (control), fertilized with chicken droppings, fertilized through the composter and fish-rice farming were tested in four repetitions each. The ponds were stocked with male fry of Oreochromis niloticus (22.68±2.22 g; 0.5 ind/m²) and with juveniles of Heterotis niloticus (70±1.12 g; 1 ind/100 m²) and Cyprinus carpio (40.33±7.02 g; 1 ind/100 m²). Water physicochemical characteristics and zooplankton production parameters (rotifers, cladocerans and copepods) were collected monthly. The fish were weighed and measured at the beginning and end of the study according to standard methods. Results: The dissolved oxygen, nitrite and nitrate values were higher in fish-rice ponds. The highest density values for rotifers (11.354±1803 ind/L), cladocera (1769±502 ind/L) and copepods (11.117±2107 ind/L) were recorded in ponds fertilized with chicken droppings. As for species richness, rotifer (23), cladoceran (13) and copepod (11) were richer, respectively, in ponds fertilized with chicken droppings, fish-rice farming and composter. The highest weight gain values of Oreochromis niloticus (508.33±183.20 g), Heterotis niloticus (2341.67±291.54 g) and Cyprinus carpio (1405.03±307.12 g) were obtained in ponds fertilized with chicken droppings. Conclusion: A polyculture of fish in ponds fertilized with chicken droppings gives better results in terms of the quantity of zooplankton and fish produced. It should also be encouraged in fish-rice ponds and compost ponds to improve the quantitative production of fish.

Efficacy of a Neonicotinoid, Imidacloprid to Clarias batrachus Linnaeus (1758) in Relation to Selected Environmental Variables

10 June, 2026

Background and Objective: The toxicity of pesticides is found to significantly vary with some environmental variables such as temperature, pH, hardness, etc. which adversely affect non-target organisms, particularly fishes and human beings. Therefore, the objective of the work was to compare the acute toxicity of a neonicotinoid insecticide (Imidacloprid) to a freshwater fish, Clarias batrachus (Linnaeus) in supply water and tube well water at two different selected pH strengths. Materials and Methods: There are a total of 720 acclimatized test fishes (5.0±0.5 cm) were taken for experiment in both supply water and tube well water at two different selected pH strengths and natural hardness. A full-scale static bioassay test has been carried out for a period of 96 hrs to analyze the LC₅₀ values, 95% confidence limits by Probit analysis (SPSS, Version-16), presumable safe and safe dischargeable concentrations of Imidacloprid 70% WG for the test fishes. Results: The 96 hrs LC₅₀ of Imidacloprid 70% WG were noticed to be 233.436 and 251.641 ppm (p<0.05) at pH 5.5±0.2 and 8.5±0.2 for supply water however, these values were reported as 343.779 and 429.947 ppm (p<0.05) for tube well water at pH 5.5±0.2 and 8.5±0.2, respectively. Moreover, any alteration in behavioural response in the exposed fishes has also been noticed during static bioassay. The safe or harmless concentrations of Imidacloprid 70% WG were estimated too high compared to safe dischargeable concentrations for both waters. Conclusion: The toxicity (LC₅₀values) of a neonicotinoid, Imidacloprid is found to be significantly altered with selected environmental variables and exposed fishes exhibit abnormal behavioral responses.

Journal of Fisheries and Aquatic Science - Current Issue

Evaluation of the Ecological Potential of Fish Production Ponds in the Eastern Region of Cameroon

Efficacy of a Neonicotinoid, Imidacloprid to Clarias batrachus Linnaeus (1758) in Relation to Selected Environmental Variables