The Seneca Park Zoo says its 21 year old male sea lion named "Flounder" has died.

Officials say the average life expectancy of a sea lion is just over 19 years. Flounder died in his sleep. He was being treated for age-related joint pain.

Flounder was born at the Seneca Park Zoo, and was the last surviving sea lion from a group that once lived in the Zoo's main building.

Two other sea lions, two 3-year old females, Lily and Marina, now live at the Zoo's Rocky Coasts exhibit.

The zoo does not plan to replace Flounder immediately.