Red Tides Possibly Caused the Largest Whale Stranding in History
A sei whale mother and calf. Some 337 whales, likely seis, were found off the coast of southern Chile in the largest stranding ever recorded. (Christin Khan, NOAA / NEFSC)
When scientists spotted 337 dead whales off the coast of Chile’s Patagonia, it raised immediate concerns. It’s the largest whale stranding ever recorded — posing more questions than offering answers.
The primary theory? The whales fell victim to red tides, or toxic algal blooms. The microorganisms contained in some algae, which might be fueled by climate change-caused warming oceans, are also a possible root behind an “unusual” whale die-offoff the coast of Alaska this summer. As for the mechanism at work, it might be because the whale’s prey ingested the microtoxins before the whales did, Bree Witteveen, Ph.D., a marine mammal specialist at the University of Alaska, Fairbanks, who is studying the Alaska stranding, told weather.com.
This is just speculation for both events, however. “While [algae] is pretty high on the list of things we’re considering, we’re not ruling anything out at this point,” Witteveen said.
The lead scientist on the Chilean stranding, Carolina Simon Gutstein of the Universidad de Chile and Consejo de Monumentos Nacionales in Santiago, told weather.com in an email scientists are studying the cause of death and hope to publish on it soon. For now, she won’t speculate further.
Gutstein discussed her work with National Geographic after local Chilean press got wind of the story. She said many of the whale carcasses are extremely decayed — plus they’re in remote, hard-to-access areas, so species identification has been tough. Endangered sei whales are the most-likely scenario, she said.
Nat Geo writes:
“… sei whales are large, bluish-gray baleen whales that filter the water to feed on krill and other small creatures. They can reach 64 feet (19.5 meters) long and 50 tons. Considered the fastest cetacean, sei whales can swim at speeds up to 31 miles (50 kilometers) per hour. Their lifespan is 50 to 70 years, and they are usually found in deep waters far from coastlines. The worldwide population is estimated at about 80,000.”
As to whether climate-fueled algae blooms and the other impacts of warming oceans will continue to create issues for whales, Witteveen said that’s a matter for investigation, as well. Whales are resilient large mammals that migrate long distances — sometimes thousands of miles — so many are used to changing ocean temperatures. A likely scenario is that warming oceans could impact whale’s prey, Witteveen said.
“Whenever a large number of animals die, it can serve as a bit of a warning, a signal, that we need to take a closer look,” she added. “[It] adds another piece to the climate change puzzle.”