Mystery surrounds the arrival of a young seal in a Utrecht canal, which was rescued by police on Thursday evening.

The seal was spotted swimming through the Oudegracht by passers-by who warned the police. The seal is said to be in good shape and is being transferred to the seal sanctuary in Stellendam, broadcaster Nos says.

‘She is doing well,’ said carer Jaap van der Hiele. ‘She is not very thin, is healthy and eats fish.’ According to some media reports, the seal had climbed out of the canal by the time the emergency services arrived.

How the seal came to be in the canal remains a mystery, but seals do occasionally make it past the sluice gates, Van der Hiele said. ‘We’ve got one which comes through every now and then and then goes back out after a couple of days.’

In 2014, photographs of a seal in the Utrecht waterways turned out to be an April 1 hoax, and there was another hoax involving photographs purporting to show a seal in Utrecht in January this year.