How rare is it to see a dolphin in the River Orwell, Ipswich?

WDC said it was not unusual for a dolphin or porpoise to swim upriver in the UK, but it was still an unusual sight.

Last year, a pod of dolphins was spotted in the River Orwell at a marina in Woolverstone, which is much further downriver and, crucially, the dolphins were seen frolicking in a group and thought to be following food sources. Common dolphins are used to depths of 200m (656ft), so the risk of stranding was a concern at the time.

In March, a dolphin also managed to make it to the depths of the Cambridgeshire Fens. Even a direct swim via the River Great Ouse in King’s Lynn, Norfolk, would have involved a distance of some 28 miles (45km) through unfamiliar territory, including two major sluices. It had been monitored but disappeared and was found dead beside the New Bedford River at Mepal, near Ely.

At the time, Dan Jarvis, director of welfare and conservation at BDMLR, said it was “exceptional” to see a dolphin in that part of the county.

Other instances include when two dolphins swam 45 miles (72km) inland, to near Huntingdon. They both died. And in July, the Cetacean Strandings Investigation Programme said a dolphin had travelled the furthest west up the River Thames for a common dolphin. It was found dead at Richmond upon Thames.