Biomarkers and Total Protein Content as Indicators of Environmental Pesticide Pollution in Fish: A Systematic Review Focused on Africa

The indiscriminate use of pesticides in agricultural systems has resulted in extensive contamination of aquatic ecosystems, with profound consequences for biodiversity and human health. Fish are particularly vulnerable to these contaminants and are widely recognized as effective bioindicators due to their ecological relevance, sensitivity to pollutants, and importance in human consumption. Scientific evidence shows that pesticide exposure in fish leads to a range of biochemical and physiological alterations, which can be detected through effect biomarkers such as antioxidant enzymes, oxidative stress indicators, and enzymatic activities. In addition, reductions in total protein content in fish tissues have been consistently associated with physiological stress and disrupted metabolic functions. This systematic review aims to critically evaluate African studies that have investigated pesticide contamination in fish using biomarkers and total protein content as indicators of toxicological stress. By synthesizing this evidence, the review seeks to identify consistent patterns across species, pesticide classes, and exposure conditions, while also highlighting sensitive biomarkers and tissues most affected by pesticide exposure. The expected outcomes include a clearer understanding of how biomarkers and protein content can serve as early-warning tools for environmental monitoring, support for the development of more integrated approaches to pesticide risk assessment, and contributions to public health and sustainable management of aquatic resources in Africa.