Scientists suspect algal toxin killed over 20 endangered sei whales along Chilean coast

A group of foreign scientists made a gruesome discovery along Chile’s southern coast on the Gulf of Penas on April 21. Over two dozen dead sei whales, averaging 33 feet in length, had washed up along the beach.

The scientists immediately reported their find to the National Fisheries Service. A statement from Chilean officials says there were about 20 whales while the scientists insist there were more than 30 whales.

The International Union for Conservation of Natures (IUCN) lists the sei whale, Balaenoptera borealis, as endangered under criterion A1 because the decline in population could be considered reversible.

The sei whales were heavily hunted after populations of blue and fin whales were depleted. The sei whale population today is estimated to be around 12,000.

It is not that unusual to find whales beached along Chile’s 4,200 kilometer coastline, but this is the first time sei whales have been found. German biologist Vreni Haussermann was leading the group of scientists who found the whales. “They were everywhere, none were injured, so we thought they suffered from a red tide [algal bloom] or a virus,” he said.

Officials say they are investigating the mass stranding to determine how the whales died, but the investigation has been hindered by bad weather.

One of the biggest reasons for repeat mass strandings is the toxins from harmful algae blooms. These blooms are quite common along the coastlines of continents, and the algae blooms are enhanced by rich nutrients, like iron, released from the soil during erosion and carried to the ocean by rivers and streams.

Because the Andes Mountains of South America are rich in iron, the runoff from erosion has been going on for over 20 million years, and sea mammal strandings are very common along the

South American coastline. Sea mammals consume prey that have eaten toxic algae, or breath the toxins, causing a fairly rapid death at sea.

 

 

Photo: Over 20 endangered sei whales found washed up dead along coast of Chile.

View original article at: Scientists suspect algal toxin killed over 20 endangered sei whales

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