Why are dolphins in the Amazon rainforest dying? Causes explored as more than hundred marine mammals found dead since last week

The carcasses of more than 120 dolphins were found floating in the Brazilian Amazon rainforest last week, as per NPR. Amid this, the Mamiraua Institute, a research group of Brazil’s Ministry of Science, Technology, and Innovation, reported that two more carcasses of dolphins were found near Tefe Lake, much to the alarm of marine specialists.

AP News reported that experts believe these deaths were likely caused by high water temperatures. They further explained that the water temperature in the past week has gone above the mark of 39 degrees Celsius (102 degrees Fahrenheit). Detailed investigation into the deaths of the water mammals are currently underway.

Disclaimer: This article deals with the death of animals and may be disturbing to some readers. Readers' discretion is advised.

---

Drought and increasing water temperatures likely tied to the death of the dolphins

According to NPR, a Brazilian government-run organization named Chico Mendes Institute for Biodiversity Conservation has sent their team of veterinarians to investigate the matter.

Experts have determined that the recent surge in the deaths of these water mammals is likely because of the drought in the area. Other than this, they also pointed out that high water temperatures are also responsible for this unfortunate outcome. Reuters reported that scientists are working to eliminate other possible causes like a bacterial infection that could have caused such a largescale death.

A researcher from the Mamiraua Institute, Miriam Marmontel, shared that there had been around 1,400 river dolphins in the past in the Tefé lake. However, because of the increased death rates, the number is likely to have dropped. Marmontel told AP News:

"In one week we have already lost around 120 animals between the two of them, which could represent 5% to 10% of the population."

As per Reuters, the water in Lake Tefé 39 degrees celsius last Thursday. The normal temperature of the water around this time of year is approximately 10 degrees lower.

---

Amazonas governor Wilson Lima declares a state of emergency

On Friday, September 29, 2023, Amazonas governor Wilson Lima declared a state of emergency owing to the drought in the region. Nicson Marreira, mayor of Tefe, also spoke about how the government was unable to deliver food to some areas because the rivers were dry.

Ayan Fleischmann, the geospatial coordinator at the Mamiraua Institute, said that the drought has adversely affected riverside communities in the Amazon region:

"Many communities are becoming isolated, without access to good quality water, without access to the river, which is their main means of transportation."

Fleischmann concluded by saying that they are still investigating the cause of dolphins' death but for now, the main reason behind this is high water temperature.