Dozens of beluga whales, captured in Russia and kept in cramped conditions, have finally been released.

Almost 100 were caught illegally last year - along with 11 orcas - in the Sea of Okhotsk, some 800 miles (1290km) north of the Pacific port of Nakhodka where they were held in so-called "whale jails".

It is thought the whales were set to be sold to Chinese amusement parks.

Their plight caused an international outcry, with Hollywood star Leonardo DiCaprio backing a petition, which received more than a million signatures, calling for the mammals to be set free.

Image: Russian authorities say the operation began five days ago

In a statement, the Russian Research Institute for Fisheries and Oceanology said: "An operation on the release of the sea mammals to their natural habitat in the region of Primorye has been completed.


"All the remaining belugas were released in the Bay of Assumption on Sunday 10 November".

Image: Russia says it has completed its operation to free all the captured mammals

The Kremlin stepped in after the whales were captured, with President Vladimir Putin ordering local authorities in the Russian far east to intervene - officials then started releasing them in batches in late June.

Russia's FSB security service brought charges against companies involved in the capture for breaking fishing laws.

:: A New Climate is a series of special podcasts from the Sky News Daily. Listen on Apple Podcasts, Google Podcasts, Spotify, Spreaker

The Kremlin said Russia has no direct ban on catching whales, but that they can only legally be caught in specific circumstances, such as for scientific and educational purposes.

Image: A view of enclosures with nearly 100 whales being held captive

Prior to their release, the whales were transported for six days across 1,100 miles (1,800 km) - which was criticised by Greenpeace and international scientists, who said the process had been rushed, conducted in secret and may have put the animals at risk.

Incredible footage has emerged showing South African rugby fans playing catch with a beluga whale near the North Pole 🏉🐋



For more news from around the world, click here 👉 https://t.co/cJcF9DpspF pic.twitter.com/cXleMzdRAJ — Sky News (@SkyNews) November 8, 2019

Russian authorities say the operation to release the last of the captured whales began five days ago.