November 2025 has been rich with events in the world of dolphins — from touching stories of population recovery to alarming signals of ecological disasters. We present to you a brief digest of the most significant news about marine mammals that occurred this month. From positive examples of dolphins returning to recovering ecosystems to the dramatic consequences of climate change — these events demonstrate the complexity of the relationship between humanity and nature.
VENICE: DOLPHIN MIMMO BECAME A STAR OF SAN MARCO LAGOON
An unusual guest has settled in the heart of historic Venice — a young bottlenose dolphin whom local media named Mimmo. The animal entered the Venetian lagoon and has since become a permanent resident of the San Marco Basin area, delighting tourists with acrobatic jumps. Marine biologist Luca Mizzo notes that the dolphin remains in the area even after feeding and does not show signs of distress from the noise of water taxis and gondolas.
However, experts are concerned that Mimmo may be injured by the propellers of ships that ply the busy lagoon daily. Attempts by specialists to return the dolphin to open water have not been successful — the animal clearly has no intention of leaving Venice. Mimmo's case is viewed as a positive sign of improving ecological conditions in the Venetian lagoon, where invasive species are decreasing and the natural ecosystem is recovering. The return of wild dolphins to Venetian waters confirms the positive changes that have occurred since the COVID-19 lockdowns.
TAGANROG BAY: A WAVE OF DEATHS OF ENDANGERED HARBOUR PORPOISES
In early November 2025, a tragedy occurred on the coast of Taganrog Bay — local residents and sailors discovered the dead bodies of dolphins, which are biologically known as harbour porpoises (Phocoena genus). Lifeless bodies were washed ashore in several locations: near the village of Beglitsa, on the Pavlo-Ochakovsky Spit, and in the maritime port.
Harbour porpoises grow up to one and a half meters and weigh about 30 kilograms. Their natural habitat is the coastal waters of the Black Sea, but in warm seasons they migrate to the Azov and Marmara Seas, sometimes entering the Don and Danube rivers. Similar cases occurred a year ago — necropsies of animals showed serious liver and stomach disease caused by viral infection. The exact cause of the current wave of deaths has not yet been determined. Ecologists point to numerous negative factors: water pollution, reduction of food sources, and changing temperature conditions in the Azov Sea. The harbour porpoise is listed in the Russian Red Book and is under special state protection.
AMAZON: EXTREME HEAT KILLED HUNDREDS OF PINK RIVER DOLPHINS
A study published in the prestigious journal Science revealed the cause of the tragic death of hundreds of pink river dolphins in the Amazon. Leading researcher Ayan Fleischmann from the Mamirauá Institute for Sustainable Development found that extreme heat and drought of 2023–2024 were responsible, transforming Amazon waterways into "boiling baths."
During the drought, water temperatures in central Amazon lakes exceeded 40°C. In Lake Teffé, about two meters deep, temperatures as high as 41°C were recorded — higher than in a hot tub. According to Fleischmann: "We could not even dip our fingers in the water. It was hot not only on the surface but all the way to the bottom." Over the course of six weeks in September 2023, approximately 200 pink river dolphins — an extremely rare species facing extinction — washed ashore on Lake Teffé. Local residents and scientists had never before witnessed such massive death tolls.
Over the past three decades, Amazon lakes have warmed at a rate of 0.3–0.8°C per decade — twice as fast as the world's oceans. During the 2024 drought, Lake Teffé's area shrank by 75%, and neighboring Lake Badahos by 90%. The mass death of pink dolphins has become a symbol of ecological catastrophe. These animals are sensitive to changes in temperature and oxygen levels. When water overheats, it loses its ability to hold oxygen, and dolphins suffocate even while at the surface. Simultaneously, fish — the primary food source not only for dolphins but also for local populations — die in massive numbers.
According to the research, the heat and drought were linked to an intensification of the El Niño phenomenon and global warming. Atmospheric patterns delayed rainfall, reduced cloud cover, and increased the radiation balance — a combination that turned lakes into heat traps. Massive forest clearing reduced evaporation, depriving the region of its natural "coolant." If similar conditions recur, freshwater ecosystems will be unable to recover, and the extinction of river dolphins will become not an isolated incident but a trend.
VENICE: DOLPHIN MIMMO BECAME A STAR OF SAN MARCO LAGOON
An unusual guest has settled in the heart of historic Venice — a young bottlenose dolphin whom local media named Mimmo. The animal entered the Venetian lagoon and has since become a permanent resident of the San Marco Basin area, delighting tourists with acrobatic jumps. Marine biologist Luca Mizzo notes that the dolphin remains in the area even after feeding and does not show signs of distress from the noise of water taxis and gondolas.
However, experts are concerned that Mimmo may be injured by the propellers of ships that ply the busy lagoon daily. Attempts by specialists to return the dolphin to open water have not been successful — the animal clearly has no intention of leaving Venice. Mimmo's case is viewed as a positive sign of improving ecological conditions in the Venetian lagoon, where invasive species are decreasing and the natural ecosystem is recovering. The return of wild dolphins to Venetian waters confirms the positive changes that have occurred since the COVID-19 lockdowns.
TAGANROG BAY: A WAVE OF DEATHS OF ENDANGERED HARBOUR PORPOISES
In early November 2025, a tragedy occurred on the coast of Taganrog Bay — local residents and sailors discovered the dead bodies of dolphins, which are biologically known as harbour porpoises (Phocoena genus). Lifeless bodies were washed ashore in several locations: near the village of Beglitsa, on the Pavlo-Ochakovsky Spit, and in the maritime port.
Harbour porpoises grow up to one and a half meters and weigh about 30 kilograms. Their natural habitat is the coastal waters of the Black Sea, but in warm seasons they migrate to the Azov and Marmara Seas, sometimes entering the Don and Danube rivers. Similar cases occurred a year ago — necropsies of animals showed serious liver and stomach disease caused by viral infection. The exact cause of the current wave of deaths has not yet been determined. Ecologists point to numerous negative factors: water pollution, reduction of food sources, and changing temperature conditions in the Azov Sea. The harbour porpoise is listed in the Russian Red Book and is under special state protection.
AMAZON: EXTREME HEAT KILLED HUNDREDS OF PINK RIVER DOLPHINS
A study published in the prestigious journal Science revealed the cause of the tragic death of hundreds of pink river dolphins in the Amazon. Leading researcher Ayan Fleischmann from the Mamirauá Institute for Sustainable Development found that extreme heat and drought of 2023–2024 were responsible, transforming Amazon waterways into "boiling baths."
During the drought, water temperatures in central Amazon lakes exceeded 40°C. In Lake Teffé, about two meters deep, temperatures as high as 41°C were recorded — higher than in a hot tub. According to Fleischmann: "We could not even dip our fingers in the water. It was hot not only on the surface but all the way to the bottom." Over the course of six weeks in September 2023, approximately 200 pink river dolphins — an extremely rare species facing extinction — washed ashore on Lake Teffé. Local residents and scientists had never before witnessed such massive death tolls.
Over the past three decades, Amazon lakes have warmed at a rate of 0.3–0.8°C per decade — twice as fast as the world's oceans. During the 2024 drought, Lake Teffé's area shrank by 75%, and neighboring Lake Badahos by 90%. The mass death of pink dolphins has become a symbol of ecological catastrophe. These animals are sensitive to changes in temperature and oxygen levels. When water overheats, it loses its ability to hold oxygen, and dolphins suffocate even while at the surface. Simultaneously, fish — the primary food source not only for dolphins but also for local populations — die in massive numbers.
According to the research, the heat and drought were linked to an intensification of the El Niño phenomenon and global warming. Atmospheric patterns delayed rainfall, reduced cloud cover, and increased the radiation balance — a combination that turned lakes into heat traps. Massive forest clearing reduced evaporation, depriving the region of its natural "coolant." If similar conditions recur, freshwater ecosystems will be unable to recover, and the extinction of river dolphins will become not an isolated incident but a trend.