Scientists are baffled by the massive numbers of dying baby southern right whales in the area of Patagonia. Furthermore, these deaths are occurring 10 years after what the Wildlife Conservation Society (WCS) has referred to as the beginning of the "worst die-off" on record for the species, that is still continuing today.
Infectious diseases don't seem to be causing the die-off of so many whales in the region, and toxins haven't shown up in the whale tissue studied. Some believe that the massive die-off of southern right whales might have something to do with whale blubber-eating birds.
According to the WCS, as relayed by LiveScience, there have been 605 deaths of southern right whale babies since 2003 in "peaceful Atlantic bays around Peninsula Valdes along Argentina's Patagonian Coast," where the whales are known to travel in order to birth and raise their young.
More than 530 of the southern right whales that died were newborn calves. There were 116 such deaths last year alone — the most severe die-off of the species on record — with 113 of the whale deaths being babies.
"In 2012 we lost nearly one-third of all calves born at the Peninsula," Mariano Sironi, scientific director of the Instituto de Conservacion de Ballenas in Argentina, said. Sironi also advises the Southern Right Whale Health Monitoring Program.
"Southern right whales have their first calf when they are nine years old on average," Sironi said. "This means that it won't be until a decade from now that we will see a significant reduction in the number of calves born, as all of the female calves that died will not be contributing any new offspring to the population."
Sironi, along with his colleague Vicky Rowntree, have been observing the southern right whales for some time and believe that the cause of the massive die-off might be related to kelp gulls that are eating the skin and blubber of the whales.
"The attacks are very painful and cause large, deep lesions, particularly on the backs of young 2-6 week-old calves," the researchers said via a statement from the WCS. "This harassment can last for hours at a time. As a result, right whale mothers and their calves are expending much precious energy during a time of year when mothers are fasting and at a site where little to no food is available to replenish fat reserves."
One of the most frustrating aspects of the die-off is that the whales had only recently made a comeback from numbers that dwindled due to the whaling industry.
"The southern right whale population is still only a small fraction of its original size, and now we have reason to worry about its recovery," Rowntree said.
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