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March 24, 2023

How is the “bird flu” affecting marine life?

Humbolt penguins are among the species affected by the bird flu in South America. ©OCEANA/Eduardo Sorensen


Oceana’s Science Director in Chile, Dr. Matthias Gorny, explains the disease and its broadening scope in South America 

By Matthias Gorny 

The “bird flu” (also known as the avian flu) has not only affected millions of chickens, geese, and ducks around the world – it has spread to sea birds, all the way from the north Atlantic to the coasts of Central and South America. It’s also affecting marine mammals. New reports find the virus responsible for the deaths of thousands of sea lions. 

Where did the virus come from? 

Bird flu is caused by the H5N1 virus and was detected in 1996 in large numbers of geese in East Asia. It rapidly spread to other poultry. In 2014, a new, highly contagious form of H5N1 was detected. This version of the virus has adapted to attack wild birds, including seabirds.  

How is the virus distributed? 

The virus is distributed when wild birds migrate, and seabirds are especially migratory. Thanks to migration patterns, the virus has expanded from North America to South America, including countries such as Chile, Ecuador, and Peru. The bird flu has also affected seabirds in the Atlantic, even reaching as far as the Arctic. 

We’ve also seen indications in Europe and the United States that the virus is being distributed differently among birds that migrate in the winter and those that migrate during the summer. 

Which marine species are affected?  

The virus is not always deadly. Some species are more resistant than others, a subject that is still being studied. Some research suggests the migratory behavior of different birds affects the distribution of the virus around the world. Seabird species such as pelicans, gulls, and terns are among the most likely to get sick, with pelicans being most affected. In addition to birds, the virus has been transmitted to mammals such as sea lions and dolphins.  

How do we prevent transmission?  

First of all, try to avoid contact with farmed and wild birds as much as possible. Bird feathers and excrement are sources of transmission, so be mindful of activities (such as transporting boats), that could put you in contact. The virus is also transmitted through clothing worn by people, so it’s best to avoid visiting colonies of wild birds. 

What is the situation in Chile and Peru?  

Since Peru recorded its first case of bird flu in November, the virus has since killed more than 63,000 birds, Peru’s national parks service (Sernanp) reported. The most affected species include Peruvian pelicans, which are endangered. In February 2023, Sernanp recorded the deaths of 3,487 sea lions (3.29% of the total population in Peru) as well as five fur seals. 

Chile’s National Fisheries and Aquaculture Service (Sernapesca) reported that sea lions, sea otters, and Humboldt penguins – 763 in total – have died during the first quarter of 2023 as result of the bird flu outbreak in Chile. The virus has been recorded in at least 11 regions of Chile and in at least 21 seabird species. It seems to be spreading southward – and veterinarians from the University of Chile and other institutions are currently investigating Antartica for potential impacts.