Shark seen swimming upstream in river 8km from sea

A shark's fin was spotted. File photo / Doug Sherring

The dirty water of the Whanganui River is not popular with swimmers - and it's just as well after a shark was spotted about 8km upstream yesterday.

Crowds gathered to watch the unusual visitor and once told, police warned river users to be on alert.

Kelly McIntyre, 26, said she was visiting a friend on Somme Parade overlooking the river when her mother Leanne pointed to something swimming upstream. "My mum saw it first and said 'what the hell is that'? We got binoculars and sure enough I saw a big triangle sticking up out of the water. It was dark grey or black and was quite clearly a dorsal fin," she said.

The McIntyres were concerned about children nearby who were at the edge of the river fishing.

"We called the police and went down to the river and yelled at people to get out of the water. People often walk their dogs and let them go into the water so we were worried about that too," she said.

The mother and daughter followed the fin to the Dublin St Bridge. "We saw it pass under us. It was pretty crazy. A guy from the Department of Conservation and the police met us at the bridge and confirmed it was a shark," she said.

"It was quite visible; we stood on the bridge and could still see it going around, circling and zig zagging. I'm gutted I didn't get a photo. It was a shocking thing to see and I didn't even think to get my camera," she said.

The shark had swum up river from the Tasman Sea about 8km away.

She said a large crowd gathered to see the shark along the river banks. "I've lived here all my life and never heard of sharks swimming up the river. It's crazy," she said.

It was last seen at about 12.10pm about 200m north of Dublin St bridge.

Acting Sergeant Michael Roycroft said a number of people had seen the shark, including himself.

"We saw a dorsal fin in the water.

"I have no idea what kind of shark it was but it appeared to be about a metre to a metre-and-a-half long."