A Christchurch beachgoer has described the moment he and a stranger attempted to save a stranded shark, only for it to wash up dead the next morning.

Murray Crowley, who was visiting from Dunedin, came across the shark at Sumner Beach while going for a swim Thursday.

He said another beachgoer was already on the phone to the Department of Conservation when he arrived.

“I walked up and asked if she wanted me to try and drag it back in, and she didn’t really say anything, so I had a crack on my own.”

“It was pretty bloody heavy, so I went for a swim and then when I come back, there was another guy standing there and he gave me a hand to drag it back into the water.”

Murray estimated the shark weighed well over 100kg, which made the rescue “pretty hard going.”

Once the shark was in the water, he and the other rescuer watched to see if it would swim away.

“It wasn’t really turning around to get at us. It was tracing around a wee bit, but once we got out into the water, we sort of stood there to see if it was gonna swim away. It was pretty clear it wasn’t.”

Despite their efforts, the shark was in distress when they got it back into the water.

“It was pretty miserable. It sat there for a bit and then it tried to swim, and then it just rolled on to one side for a bit,” he said.

“I buggered off not long after that, and then we went back in the morning and it was dead.”

He said he had noticed a puncture wound through the shark’s tail, which he wondered was the cause for the shark washing up.

“It was pretty cool... It’s not every day you try and drag a shark into the water... Afterwards, when I thought about it, I was like ‘that probably wasn’t that smart'.”

The shark, described by one witness as juvenile and just under 2 metres long, prompted a police call out around 8.30pm on Friday night, who referred the event to DoC.

DoC Mahaanui Operations Manager Andy Thompson said mako sharks were not a protected species, so DoC does not manage their population and is not mandated to respond to incidents like this.

“The stranding is a sad but natural event,” he said.

Ben Tomsett is a Multimedia Journalist for the New Zealand Herald, based in Dunedin