Tatiana Mironenko / Getty ImagesTemperatures higher than the current average damaged the tambaqui’s DNA and liverTatiana Mironenko / Getty Images
Native to the Amazon and consumed nationwide, the tambaqui (Colosoma macropomum) is sensitive to pesticides found in rivers in the North of Brazil. The effects of the pesticides worsen — and the fish’s defenses against contamination fall even further — when the water is warmer than current temperatures, which the Intergovernmental Panel on Climate Change (IPCC) has predicted will rise. Researchers from the Brazilian National Institute of Amazonian Research (INPA) and the Federal University of Amazonas (UFAM) subjected 36 young tambaquis, with an average weight of 35 grams and length of 10 centimeters, to experimental conditions for 96 hours. They evaluated the effects of a mixture of four pesticides (the insecticides chlorpyrifos and malathion, the fungicide carbendazim, and the herbicide atrazine) under current environmental conditions and the conditions projected for 2100 (warmer by 5 degrees Celsius and with CO2 levels of 700 parts per million) on the blood, gills, liver, brain, and muscles. The pesticides caused harm even at low concentrations. The higher the temperature, the more intense the changes in antioxidant enzymes, DNA, and the liver, reducing the ability to adjust to climate change. Conclusion: the combination of external stimuli could threaten the survival of the species. After tilapia (Oreochromis niloticus, an exotic species), tambaqui is the second most farmed fish species in the country, primarily in Rondônia, Maranhão, and Roraima. It averages 70 cm in length and can weigh up to 30 kilograms (Science of The Total Environment, April).
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