Buenos Aires ( Associated Press) – Nearly 30 southern right whales have been killed in recent weeks by harmful algal blooms in Nuevo Bay in the South Atlantic, according to Argentine researchers.
The poisonous algae, also known as red tide, spread to the waters of the New Gulf of Valdés Peninsula in the southern province of Chubut between late September and early October, when 26 adult cheetahs and four juveniles were found dead. The Whale Conservation Institute (ICB) indicated in a statement.
Biologists and veterinarians from the Southern Right Whale Health Monitoring Program, who has been working on the Valdes Peninsula since 2003, performed necrosis on six whales that were in the best condition. In addition, they collected partial samples, without opening the cavities in the other three found in areas of public use and could not be moved to any other location.
All six whales tested had material in their digestive tracts, indicating they had recently eaten before death.
“Every year we record and study whales that die in the area. Although a higher number of calves have died in previous years, this is the first time that we have recorded 30 dead adult and juvenile whales in one season and over a period of a few days. “Zoology doctor Mariano Sironi told the Associated Press and scientific director of the ICB.
In 2021, 20 were recorded, including 13 adults and seven juveniles.
Program experts will continue to work on the investigation of eight cetaceans found in advanced stages of decomposition on hard-to-reach isolated beaches in Nuevo Bay.
Concentrations of paralyzed shellfish toxins were found in various tissues and fluids in five of the six necropsid whales.
Sironi explained that the latter “contains several biotoxins produced naturally by marine phytoplankton microorganisms known as dinoflagellates.”
According to a statement published by the ICB, there are records of poisoning and death of marine organisms in the world – often affecting large numbers of animals – due to ingestion of the same paralyzing biotoxins that were found in the bodies of whales that have died. Went. Peninsula Valdes.
Sironi explained that harmful algal blooms are also known as red tides because in some cases the algae that produce them are red in color and can give that color to the ocean when they are in high concentrations. However, in many cases the water does not take on this color, as it currently does in Peninsula Valdés.
“Current evidence indicates that in the face of climate change, there may be an increase in the frequency and intensity of harmful algal blooms on a global scale, but this will depend on local conditions in each case,” the scientist said.
They reported that increases in ocean temperatures, changes in ocean currents and distribution in coastal areas and the abundance of organic matter and other factors affect the dynamics of harmful algae blooms.
Southern right whale watching is one of the main tourist activities in the Valdés Peninsula, where dozens of specimens are collected each year. The cetaceans arrive during May and remain till December to hatch and feed the calves.