Bob, the baby orca, who was struggling for life for more than 20 days has died. He was left stranded on a shore in Tauranga harbour in New Zealand when rescuers found him.

He remained separated from its mother and pod for over two weeks. A task force, which included staff from the Department of Conservation, Orca Research Trust and local Maori tribes, tried their best to reunite Bob — believed to be between six months to a year old — with his family but failed.

According to reports, he was dehydrated and sick, and did not take food provided by scientists. He was only using his own reserves of blubber to stay alive, which led to the decline in his health. The baby whale was then shifted to a pool on the shoreline from Tauranga harbour and fed electrolytes, water and fish slurry.

International orca expert Jeff Foster was also called from America last week to help in the rescue operation.

An orca in a file photo. A baby whale, named Bob by locals, died after being stranded in New Zealand harbour for 20 days Reuters

Conservation Minister Maggie Barry, said in a statement, "Sadly the calf lost its battle overnight despite the best efforts of a team of rescuers. I send my sympathies and commiserations to the many people who have worked exhaustively over the last week to try to save the young whale. It was an effort made in the best spirit of cooperation and conservation of the natural world.

"Rescue and release of an orca this young would have been a world first. The chances of success were always slim, but those who gave their time and effort to the calf should be proud of their efforts. I understand the tactical response group will make arrangements for an appropriate farewell and will not be making any further statements until these are confirmed."

"It is very unusual for a young calf to get separated from his family," The Guardian quoted Reon Tuanau, a spokesperson for Ngaiterangi tribe, a clan based in Tauranga, as saying.

"As tangata whenua [native people of New Zealand] we have a close connection with all creatures of the sea and orcas are held in high regard as a threatened species and taonga [treasure]. We are feeling very sad," he added.