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A beloved Atlantic harbor seal at Buttonwood Park Zoo died earlier this month due to complications from bird flu, zoo officials announced this week. The necropsy results come amid a widespread outbreak of the disease, which has been killing thousands of wild birds throughout Massachusetts.  

Zoo officials said on social media that the 21-year-old male seal, named Blue, began showing signs of illness on Jan. 31. Staff members noticed Blue had lost his appetite, and was frequently resting at the top of the pool in his habitat. 

Blue the seal poses for a photo at Buttonwood Park Zoo. Credit: Buttonwood Park Zoo

They removed him from the habitat he shared with two other harbor seals, and put him into a holding facility under increased veterinary observation. They provided him with a variety of treatments and diagnostic tests starting on Feb. 1. Yet Blue died of his illness at the zoo on Feb. 5, before results came in.

The veterinary team conducted a necropsy on Blue, and zoo leadership closed Buttonwood Park Zoo on Feb. 5 and 6 to allow staff to mourn the loss.

Zoo staff received the results of Blue’s diagnostic testing from the National Veterinary Services Laboratories in mid-February. They suspect Blue contracted bird flu from a wild bird. 

Bird flu has been affecting wild and domesticated animals across the country, including zoo animals. So zoo officials say the recent event at Buttonwood Park Zoo “is, regrettably, far from unique.” A harbor seal at Lincoln Park Zoo in Chicago also recently died from bird flu. 

Staff had already taken proactive steps to reduce the risk of bird flu amid the current outbreak, including removing public duck feeders and relocating vulnerable species. They say that the disease presents no risk to zoo visitors. 

Zoo leaders add that Blue’s “habitat-mates… (harbor seals) Conway and Luna remain in good health.” Veterinary and animal care teams continue to monitor its resident animals closely, and they are following strict protective protocols to prevent cross-contamination between species. 

Bird flu is a contagious viral disease of domestic and wild birds. It spreads through direct bird-to-bird contact, and via contaminated surfaces, waters or materials. Infections with highly pathogenic strains of bird flu, including the current H5N1 strain, are often deadly for these animals. 

State officials suspect “a widespread outbreak” of the disease has killed hundreds to thousands of wild birds across the state this year, and a backyard flock of 30 chickens in Plymouth County. 

It has been the deadliest year of the current outbreak for wild birds in the state. H5N1 arrived in Massachusetts in 2021. 

Bird flu can also infect and kill cows, humans, and domestic and wild animals, though cases and mortalities are rare.

Outbreaks have been known to affect harbor seals both domestically and internationally.

The Centers for Disease Control and Prevention and other public health officials say there is currently no evidence of human-to-human transmission and the risk to the general public from the disease is low. There have been no human cases of H5N1 bird flu in Massachusetts. 

State officials say people should not handle birds or other animals that are dead or appear sick. Dogs and other pets should always be leashed and away from wildlife. People should report observations of sick or deceased birds to MassWildlife, if five or more birds are found at a single location.

Email environmental reporter Adam Goldstein at  agoldstein@newbedfordlight.org