In September, a troubling scene began unfolding in Lake Tefé in Brazil. Dolphins were dying at a rapid rate and their bodies were washing ashore.
Locals have become increasingly distressed at the sight. Many of the carcasses were only partial because animals have fed on them and decay had set in.
More than 150 dolphin dolphins have been recovered so far, of which there are two species: pink river dolphins and tucuxi river dolphins. Investigations are still underway to see if there is a disease or toxin present in the water. But the current theory is that the water is too hot.
Lake Tefé Water Conditions
By late September, Lake Tefé was measuring 102 degrees Fahrenheit. That’s far warmer than it traditionally is during that time of year. Experts referred to it as “soup.” The water levels have also reached their lowest level in over a century amidst a record drought that has lasted three months.
Exceptionally high water temperatures result in a drop in dissolved Oxygen effecting everything from fish to dolphins. Scientists have witnessed dolphins becoming disoriented, swimming in circles and unable to dive down.
The situation has led to a gathering of dozens of researchers, conservationists and veterinarians all looking to shed light on the situation and help where they can.
Scientists have been observing and relocating sick dolphins to rehabilitation pools where they can be closely monitored. Simultaneously, they are collecting the deceased animals to harvest tissue samples to learn more about the cause and how to predict and better respond to these types of emergencies in the future.
One challenge experts are facing is the remote location of Lake Tefé. It’s located 2,000 miles from Rio de Janeiro and 1,850 miles from São Paulo. With the ongoing drought, transportation via waterways is especially difficult because many smaller parts of the Amazon River are dry.
Another challenge researchers are facing is that many of the carcasses are in such poor shape that they are hard to pull samples from. Keeping the samples frozen during transport in such a remote area is complicated.
Dolphins are not the only ones suffering. The drought and challenges with the waterways have led to a state of emergency in many municipalities in the Amazonas. Many communities are without quality water and transportation.
Brazil’s Science Ministry says the drought is likely due to the El Nino climate phenomenon, which is causing extreme weather everywhere. And tragically, there is no end in sight.
Experts believe that the drought will hang on until December when the El Nino effects will begin to lessen. Dolphins are not the only ones at risk. Other marine life are dying off at incredible rates as well.
About Pink River Dolphins
Pink river dolphins live in freshwater and are found throughout the Amazon and Orinoco River basins. The cetaceans weigh an average of 352 pounds and can grow up to 9.2 feet in length.
Although the dolphins are abundant, they are considered a vulnerable population due to human interaction that has led to new dams that limit their range and are fragmenting and threatening the population.
They also face threats from contamination to their environment.
Fishermen also see the pink river dolphin as a competitor for diminishing fish stocks. As such, fishermen are using the dolphin as bait or killing them to keep them from further diminishing the fish population.
If their homes aren’t preserved, the marine life will become at risk alongside other creatures who all rely on the same ecosystem.
Global Implications
If the drought lasts as long as experts believe it might, Lake Tefé stands to lose 10 percent of its dolphin population. But the crisis isn’t just about dolphins. It underscores the importance of addressing climate change to protect biodiversity.
River dolphins sit at the top of the food chain. They help regulate Amazonian river life. And because they are some of the largest aquatic animals, they are the first to suffer environmental impacts and can provide indications of risks to overall wellbeing in the area.
Although it’s a challenging situation, the death of these dolphins is bringing to light the need for improved conservation efforts. Understanding how environmental impacts affect marine life is important and researchers are doing their best to document the situation happening in Brazil to take away key lessons to determine future action during extreme weather events and changes to marine life habitats.
As new information comes to light in the situation, new policies are needed to protect pink river dolphins and other wildlife during extreme weather events.
To get involved consider supporting the National Marine Mammal Foundation in providing financial support for researching and ending the situation in Brazil and similar events worldwide.
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