Farm minister Piet Adema has blocked the move of eight dolphins from the Harderwijk marine zoo to China, saying he is not convinced that their welfare will be assured.

The Dolfinarium planned to send the dolphins to the Hainan Ocean Paradise in China but has not yet shown that “keeping, housing and caring for the animals in China is in line with the standards we set Dutch zoos,” the minister is quoted as saying by the AD. “On the basis of the information the park has supplied so far, I am not convinced.”

The minister has given the Dolfinarium a second chance to supply more information but “until then, animals can’t be moved”, he told MPs.

There was a storm of protest three years ago when the zoo said it wanted to sell eight dolphins, two sea lions and two walruses to China, and MPs overwhelmingly backed a motion against the deal.

In particular they were angry that the sea mammals would have to perform tricks in China, which are banned in the Netherlands.

The Dolfinarium, which opened in 1965, said in April 2021 it was transferring the animals to a new home because of subpar living conditions in the Netherlands. The animals were kept in tanks too shallow to dive to the depths they are used to.

The decision was part of a general shake up following the publication of a report by government inspectors which questioned the performances the animals were trained to take part in, the tanks they lived in and the interaction with the public, in particular the photo opportunities with dolphins and sea lions.

Several years ago the Dolfinarium and government were mired in controversy over the sale of an orca which was found in a severely weakened state in the Wadden Sea.

The whale, known as Morgan, was sent to the Dolfinarium in Harderwijk to recover. The then-junior economic affairs minister Henk Bleker, who was responsible for Morgan, decided she could not be returned to the wild and she was sold to the Loro Parque amusement park in Spain instead.

The original European CITES certificate approving the transfer stated that Morgan would be used for research purposes only. However, the orca has since become part of a show of performing animals and is being used to breed, both of which are in breach of the export licence.