The seal which was seen resting among the rocks in the sea off Bambalapitiya has gone missing since December 18, the Wildlife Conservation Department said.
The department's spokesperson Hasini Sarachchandra said yesterday there were no signs of the seal which was last seen on December 18.
"The seal must have returned to its home grounds," she said.
Ms. Sarachchandra said the seal had completed moulting when it was last seen and said it was first spotted in the sea off Mirissa on November 21 later in the sea off Bambalapitiya.
She said these creatures moult once a year, usually after the breeding season and during this period the seals cannot enter the water because they lack the insulation to keep them warm and approach land to have their skin exposed to sunlight.
Wildlife veterinary officers, wildlife western regional officers, coast conservation department officers and navy personnel were deployed to protect the seal during its stay off Bambalapitiya. (Chaturanga Samarawickrama)