Environment authorities released a video detailing the dramatic rescue of a whale shark in Abu Dhabi.
The six-metre fish was first spotted farther down the coast with a smaller juvenile in September, after following a plankton bloom into canals at Raha Beach.
It hung around for several weeks before in early November heading a few miles north up to the waters off Al Bahiyah, where it became stuck, swimming in circles in a man-made lagoon.
Authorities decided to step in after it became clear the fish was trapped and could not feed.
The whale shark, the largest living species of shark, can grow up to 12 metres and weigh as much as 40 tonnes.
“We were hoping we would not need to intervene and he would leave with the tide,” said Maitha Al Hameli, lead specialist for Marine Threatened Species and Habitats at Environment Agency Abu Dhabi.
“It’s better not to intervene when it comes to wildlife. We don’t want to stress them out.
“But when we saw that he was not going out when the tide was going out, and he was dependent on anything that came into the lagoon, we decided to come up with a plan to move him out with the National Aquarium.”
Experts first tagged the whale shark, to monitor its movements, before placing it in a water transport bag.
Jet skis then towed the big fish through the narrow entrance of the channel and 20 kilometres out into the Arabian Gulf, as free divers swam alongside to monitor it.
Data collected by the tag, which was provided by King Fahd University in Saudi Arabia, showed the whale shark had travelled 232km into the Arabian Gulf in the first five days after the rescue on November 12.
Experts said it was a good sign and showed the whale shark, which had been swimming in narrow canals in Al Raha and Al Bahiyah for three months, was healthy.
Experts said the juvenile four-metre whale shark that originally accompanied him when they first arrived in September stayed in the Al Raha area until about the same time in November, when it left abruptly.
The EAD was monitoring both whale sharks, and stepped in several times to supplement the juvenile’s diet with krill and remove fish hooks that became caught in its fins.
It also imposed a temporary ban on marine traffic in the area to protect the fish.
Abu Dhabi is typically visited by whale sharks a couple of times a year, but to have two stay for months is unprecedented.
They were both believed to have become disorientated and unable to find their way out into the Arabian Gulf.
It is not known where the juvenile is now, but experts believe it is now also back out in the open sea.
Whale sharks have a broad, flattened head with stripes and spots on their bodies and rows of more than 300 tiny teeth.
They are, however, gentle giants and filter feeders, existing on krill and plankton.
They are believed to live as long as 130 years and are found in all warm waters of the world. There are thought to be about 7,000 left in the wild.
Despite their size, some have been captured and displayed in aquariums.
A female whale shark with extensive abrasions, which was rescued from shallow waters in 2008, was briefly kept in Dubai’s Atlantis The Palm hotel. But the aquarium released it in 2010, after 19 months in captivity.
A tracker monitoring her movements fell off after 33 days, when she was in the waters off the coast of Qatar.