The Southern Resident Killer Whale population has declined slightly

A new study from the Center for Whale Research (CVR) reveals that the number of southern killer whales declined from July 2023 to July 2024. It fell from 75 killer whales at the start of the census to 73 at the end of the count.

The search for CVR shows that two adults died, and that a southern killer whale born during the census year also lost its life.

The last time observers at the research center saw the two adult killer whales, one was in poor physical condition and the other was “thin” last November.

Regarding the baby killer whale, its birth was confirmed in late December 2023 and its death occurred sometime between early and mid-January reports the CVR. Observers do not know if it was a rejection of his mother, the mother’s inability to properly breastfeed the calf with the help of other females, or kidnapping .

The CVR reports that since 2018, their population has not exceeded the number of 75 individuals, but that there are still at least 72 of these species recorded each year. In a way, the population is stagnating.

For Thomas Doniol-Valcroze, researcher and director of the cetacean research program at Fisheries and Oceans Canada, the results of the most recent census are not not really a big surprise .

According to him, what is more alarming is the loss of the newborn during the last year. That’s the real problem, because we see this population which is unable to increase and even when the young are born, they rarely survive. he notes.

What threatens killer whales

Three main causes can explain the decrease, or stagnation, of the southern killer whale population.

First, there is the lack of accessibility to their prey, mentions Mr. Doniol-Valcroze. As the Southern Killer Whale is a predatory species, its survival depends greatly on the availability of Chinook salmon. However, these fish have been decreasing in recent years.

Secondly, disturbances by human activities can affect these animals, particularly acoustic disturbance, since they are animals that communicate through sound and use sound to maintain their social cohesion.

Then, chemical contamination can also threaten southern killer whales.

These contaminations are in synergy with other threats says the Fisheries and Oceans Canada researcher. When animals are weaker due to poor diet and disturbance, they are more vulnerable to contaminants, he explains.

The Canadian government has taken protective measures in recent years. Among them, there are “particular areas closed to fishing” and sanctuary areas where all maritime traffic is prohibited,” indicates Mr. Doniol-Valcroze.

We want to try to help with all the threats we know about by telling ourselves that the cumulative effect of all these measures will have a positive effect.

Since last July, a newborn has been observed, but is not part of the most recent census. Mr. Doniol-Valcroze emphasizes that for this individual to really have an impact on the population, it must survive the first years and that upon reaching sexual maturity, he can in turn contribute to the population.

At the end of the day, we cannot hope to see results quickly. We can just continue to help in any way we can, believes the researcher.

With information from Alexandre Lepoutre