The oldest sea otter at the Aquarium of the Pacific died Friday, an aquarium spokesperson said.

Maggie, the 20-year-old sea otter, had been in declining health recently, and she died shortly after a routine blood draw intended to help assess her condition, spokesperson Marilyn Padilla said in a statement.

“At 20 years of age, Maggie was reaching the maximum age of sea otters,” the statement said. “Further tests will be performed to help determine as much information as possible to contribute further to our knowledge of the health issues experienced by geriatric sea otters.”

Maggie was 9 when she arrived at the aquarium in 2010 after being stranded and rescued.

Padilla wrote that the staff “considered Maggie to be a motherly sea otter with a kind and gentle nature.”

“Over the years when young rescued sea otters would be introduced to their new home at the Aquarium, Maggie would share food and swim gently with them,” Padilla said in the statement. “She will be greatly missed by staff and her many public fans.”