Humpback whale found dead on the coast of São Paulo

On Saturday morning (17), a humpback whale was found dead at Praia do Félix, in Ubatuba, on the north coast of São Paulo.

According to the Argonauta marine conservation institute, which was used to handle the animal, the mammal was a male measuring approximately 13 meters. An adult humpback (Megaptera novaeangliae) can reach 15 meters.

Now researchers must analyze samples of the whale’s skin, blubber and muscle to determine the cause of death. The corpse was buried with the help of the Municipality of Ubatuba.

In 2021, the stranding of humpback whales off the Brazilian coast reached an unusual number. According to a survey by Projeto Baleia Jubarte, until December 22, there were 216 episodes, a record in the historical series started in 2002.

The distant second place went to 2017, with 122 strandings.

The growth in the number of strandings still does not have a precise explanation. But, according to Milton Marcondes, research coordinator for the Humpback Whale Project, in an interview with Sheet last year, the main hypothesis is the decrease in krill.

Krill (tiny crustaceans) are one of the main foods for humpbacks, which also eat small fish. Whales suck water from the sea and “filter” their prey.

In addition to the record in 2021, there was another atypical factor in the records. Nearly 95% of stranded animals were juveniles — animals from one to five years old, when they reach sexual maturity. The life expectancy of a humpback is, according to scientists, 60 years.

“We’ve never had such a large percentage of a category,” says the expert.

The stranding of lean juveniles is another clue, according to Marcondes, that the lack of krill may have been responsible for the situation in 2021. This is because, in the event of food shortages, more experience (that is, more years of life in the sea) can help in catching food.

As a result, younger people would find it more difficult in this scenario and would reach the Brazilian coast without having had adequate food.

Adult animals also have a greater capacity to store fat, another advantage over juveniles.

The humpbacks that swim along the Brazilian coast, in general, feed in the Antarctic waters of South Georgia and come to Brazil to reproduce. By the way, the Abrolhos National Marine Park is known as an important nursery for these whales in the South Atlantic Ocean, providing cetacean watching tourism in the area.

Another sign of the lack of krill is the whales approaching the shore in search of fish. São Paulo and Santa Catarina, states with large shoals, are the leaders in strandings. There were records, Marcondes said, of animals entering fishing pens at sea looking for food and getting caught in nets.

Another record in 2021 was the —underestimated— number of animals caught in fishing nets: 58 (of these, not all died). With fishermen and whales going after the same resource, accidents like this end up becoming more likely.

Finally, another sign of the lack of krill came from afar from Brazil. Researchers from Namibia, in Africa, contacted the researcher from the Humpback Whale Project and stated that they also had above normal records of strandings and young individuals.