Over 100 dolphins have been discovered dead in a tributary of the Amazon River in Brazil over the past week. Experts suspect that the deaths may have been caused by a combination of severe drought and rising temperatures.
Approximately 70 of the dolphin carcasses were found floating in the water on a day when the temperature of Lake Tefe’s water reached an exceptionally high 39 degrees Celsius (102 degrees Fahrenheit). This temperature was more than 10 degrees higher than the usual average for this time of year.
The warming of the water is a significant concern, particularly during a severe drought when low river levels lead to higher water temperatures that become intolerable for the dolphins. Despite a brief decline, the water temperature soared to 37 degrees Celsius (99 degrees Fahrenheit) on Sunday.
The region surrounding Lake Tefe is a vital habitat for various mammals and aquatic species. Local media reports also indicate that substantial numbers of fish have died in the area.
While experts believe that drought and heat may be responsible for the increase in dolphin mortality, they are still working to rule out other potential causes, such as bacterial infections.
Miriam Marmontel, a researcher from the Mamiraua environmental institute, stated, “We have around 900 river dolphins and 500 Tucuxis (in the Tefe Lake), and in one week, we have already lost around 120 animals between the two of them, which could represent 5% to 10% of the population.” This loss poses a significant threat to the survival of these species in Lake Tefe.
Amazon river dolphins, some of which are pink in color, are a unique freshwater species found exclusively in South American rivers. Their slow reproductive cycle makes their populations especially vulnerable to threats.
The freshwater dolphins, also known as “Tucuxis,” are listed as threatened species on the International Union for Conservation of Nature’s red list.
In addition to the ecological impact, the situation has also affected impoverished riverside communities, with dry rivers causing boats to be stranded on the sand. Researchers continue to recover dead dolphins in the region as they investigate the causes of this tragic event.