Canadian researchers have flagged an alarming trend, after learning that many of the beluga whale carcasses recovered from the St. Lawrence Estuary last year were pregnant, new mothers, and newborn calves.
Since 1983, any belugas found dead along Quebec’s shores have undergone post-mortem investigations at the St-Hyacinthe veterinary centre in Montreal. It’s here where researchers found that six of the 14 carcasses recovered in 2015 were newborn calves. Another three of these whales were pregnant.
Federal research scientist Véronique Lesage told CBC News that these numbers are part of a “worrisome” trend. Of the 11 beluga carcasses recovered in 2014, six were babies. And of the 17 found in 2013, four were babies.
“The potential of the population to recover is disappearing with these deaths,” Robert Michaud, the scientific director of Quebec’s Marine Mammals Research and Education Group, told CBC News. He says the decline is approaching “crisis level.”
According to Fisheries and Oceans Canada, there are an estimated 900 beluga whales in the St. Lawrence Estuary, compared to the 10,000 that lived there a century ago. The number of belugas in the St. Lawrence has declined 1 to 1.5 percent each year since the early 2000s.
Because the carcasses of the newborn belugas showed no signs of injury, infection, or disease, it’s presumed that they died of starvation or dehydration after being separated from their mothers. Interestingly, the adult females who died were either just about to give birth or had recently done so.
Researchers say that mothers and calves could become separated due to the rise in marine traffic, since belugas use sound to communicate. But the disruption of communication between whales is just one of their theories explaining why beluga populations have declined. They also believe the drop in numbers could be the result of water contaminants such as polybrominated diphenyl ethers, the decline of valuable food sources such as herring, and the absence of ice cover due to rising water temperatures, which removes protection from wind, waves, and storms.