An unusual increase in gray whales off the coast of Baja California Sur, a species considered an invaluable natural resource that boosts tourism in fishing ports, has concerned researchers of these marine mammals.
According to data from the Marine Mammal Research Program (PRIMMA) of the Autonomous University of Baja California Sur, around 60 individuals have been found dead, a grim picture they are trying to understand.
Does La Niña have anything to do with this situation?
The presence of a high number of dead gray whales has raised several questions. To better understand this situation, Posta Baja California Sur consulted Dr. Jorge Urban Ramírez, head of PRIMMA.
The expert explained that the gray whale is a migratory species that visits the Pacific coast of the peninsula every winter to breed, after feeding during the summer at high latitudes, mainly in the Bering Sea.
Urban Ramírez noted that the gray whale population experienced stress in recent years: “Starting in 2019, 2020, 2021, and 2022, we experienced stress because their feeding grounds were affected.
So, they didn’t have enough food and energy, and when they arrived here at the lagoons, we saw them as weak and some died.”
This led to a population decline, with an estimated loss of one-third of the whales. While a decrease in mortality was observed in 2023-2024, the situation has changed this year.
“This year, several situations came together that once again affected the population. One of them was that we are in one of the so-called “Niña” years, and what this means is that the sea surface temperature is a little colder,” explained Urban Ramírez.
This change in temperature affects the whales, which tend to travel further south in search of warmer waters for reproduction.
This search for optimal conditions has led to an atypical distribution, with more sightings around Los Cabos, La Paz Bay, and Loreto.
However, this additional journey requires greater energy expenditure for the animals, which already arrive with limited reserves after the feeding season.
A very similar situation is occurring with the whale sharks in La Paz Bay, which could be affected by the La Niña phenomenon.
Is there a disturbing number of deaths and few pups?
The consequence of these factors has been reflected in a significant increase in mortality. “Right now, we’re thinking there are approximately 60 individuals dead this season,” reported Urban Ramírez.
But an even more worrying fact is the scarcity of pups.
“The interesting thing is that there are no pups. I mean, all those who have died are young or adults… but there are no pups, and there are no dead pups because the problem is that there are no live pups.
This year there were very few pups. We’re talking about the fact that, compared to the pups in 2017… this year we have about 10% of the pups from 2017.”
This low birth rate will surely have an impact on the population’s recovery in the coming years.
What’s the concern in coastal communities?
The increase in strandings and the low birth rate are causing concern in coastal communities.
In Puerto San Carlos, families like Ariel Torres’s encountered an adult gray whale stranded in front of Villas Mar y Arena:
“Well, we found out informally through social media. It’s an attraction for the girls, and we come to see it up close.”
For the tourism sector, essential to the local economy, the situation is worrying. Henry García Alvarado, captain of tourist boats, commented:
“This year there have already been around five, I think, between the Humpback and the Gray, and well, it does affect us, well, it does worry us a little. We don’t know what will happen next year. They even say there haven’t been as many births this year.”
What will happen to the future of the population?
Urban Ramírez noted that PRIMMA is collaborating with researchers from the United States and Canada to monitor the population in the summer and assess food availability in Alaska. “And then we can get a better idea of the real situation of the population,” he stated.
He also emphasized the importance of monitoring the population not only for its biological interest, but also for its value as a tourist attraction and natural resource that generates economic benefits and employment in the state.
Urban Ramírez concluded by reflecting on the continued high mortality event:
“We have to rethink whether this high mortality event that occurred in 2019, 2020, 2021, and 2022, which we thought had already passed, due to this La Niña event and the scarcity of food in the Arctic, should be considered as continuing.”
The answer to why whales are stranding in Baja California Sur is complex and multifactorial, involving everything from changes in ocean conditions linked to the “La Niña” phenomenon to potential problems in their feeding grounds.
Source: posta
