"I got it to about 50m from the shore and then it actually came disconnected from the line, so I got my son who is a good surfer to go out there and tie the line around its tail."
He said he was elated, and still a bit stunned, by the hefty catch.
"This is definitely the biggest fish I have ever caught. I must have got a bit lucky today."
Sherman believed he may have broken a national record by reeling in the first land-based marlin caught in New Zealand.
"I haven't heard of it being done before," he said. "They are usually caught off boats, a few kilometres out to sea."
He said it took four people to lift the fish, which was now prepped and cooking in the smokehouse.