Algal Blooms Linked to Largest Die-Off of Great Whales Ever Recorded

Written by Cole Mellino and reposted with permission from EcoWatch

In Argentina baby whales have been dying off the coast in increasingly high numbers for the past decade and no one has known exactly why. “The average number of right whale deaths per year at Peninsula Valdes jumped more than 10-fold, from fewer than six per year before 2005 to 65 per year from 2005 to 2014,” reports National Oceanic and Atmospheric Administration (NOAA) Fisheries West Coast Region. “Even more striking,” they say, “90 percent of the deaths from 2005 to 2014 were very young calves fewer than three months old. The mystery killer appeared to be targeting the nearly newborn, sometimes more than 100 calves of the endangered species each year.”

 This will have a long-lasting effect on the southern right whale population, explains Dr. Mariano Sironi, scientific director of the Institute de Whale Conservation in Argentina.

“In 2012 we lost nearly one third of all calves born at the Peninsula. Southern right whales have their first calf when they are nine years old on average,” he says. “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.”

Now, thanks to a report published in Marine Mammal Science, NOAA Fisheries and NOAA Ocean Service scientists and others from the U.S. and Argentina believe they have found the culprit: toxic algal blooms. These blooms have been found to pose a significant threat to fisheries and other wildlife, so it’s no surprise that the blooms are wreaking havoc on whale populations, as well.

NOAA states:

[The study] found that the number of whale deaths at Peninsula Valdes closely track the concentrations of the toxic algae Pseudo-nitzschia. The higher the density of Pseudo-nitzschia, some species of which can produce a potent neurotoxin called domoic acid, the more young whales that died. When the density of algae dropped, so did the number of deaths.

The correlation is not definitive proof that the algae caused the deaths, but is strongly suggestive.

“The numbers [of algae and whale deaths] hinge at the same point and have the same pattern,” said Cara Wilson, who led the study. “What’s unusual about this is how long these bloom events continued to reoccur. You don’t usually have deaths every year but the calves died in high numbers every year from 2007 to 2013.”


Southern right whales rely on the warm, calm waters of the Valdes Peninsula in Argentina as a calving ground. Photo Credit: John Atkinson/Ocean Alliance

The findings have implications beyond Argentina and whales. Algal blooms are expected to increase worldwide due to climate change. And if one of the largest species in the ocean is susceptible to these toxic blooms, it’s just further evidence that no species is safe. NOAA scientists are currently investigating mysterious whale strandings off the coast of Alaska. Between May and August of this year, at least 30 large whales in the western Gulf of Alaska washed ashore.

“Given the lack of solid evidence the new study does not definitively prove that the toxic algae caused the spike in deaths of whale calves. But it does offer strong circumstantial evidence, and that puts researchers in a better position to understand the possible impacts of future algal blooms,” said Gregory Doucette, coauthor of the paper.

“For us, the more opportunities we have to try to examine that relationship, to link up these mortality events to potentially toxic blooms, the better we can assess the possible effects,” he added.

Photo Credit: Thinkstock


Mark Donner
Mark D1 years ago

Might as well have a Requiem for Planet Earth, that took two billion years of hard work on the part of non human life forms to establish life and oxygen. There is no hope left when overpopulated humans are rampaging over the planet.

Siyus Copetallus
Siyus Copetallus2 years ago

Thank you for sharing.

Beata Turzová
Beata Turzová2 years ago

Je to veľmi smutné, lebo je ich málo a hrozí im vyhynutie.

Jane R.
Jane R2 years ago

Find a way to remove most of the Algae before it blooms. That might help but don't know if it's possible to do.

Claudia S.
Claudia S2 years ago

Thank you

Julia Cabrera-Woscek

Such a tragedy.

Pamela A.
Pamela A2 years ago

Lol@tell the Chinese toxic algae cures impotency and it will go away remark😀👏😄😅

Jennifer H.
Jennifer H2 years ago

With the last closing arguments it sounds like they still know nothing and the article is a big guess. But even at that I do know that the seals and sea lions are being poisoned by these algal blooms so I would not be surprised that baby whales could be affected by these blooms. But the overall big picture is that we are the cause of these blooms. Our contamination along with the warmer waters. We are the perfect storm.

Jennifer Manzi
Jennifer Manzi2 years ago


Beth Wilkerson
Beth Wilkerson2 years ago

oh crap... we have ruined so much