Lyall Nash said he caught the behemoth within 15 minutes of casting his rod on December 23.
The battle to reel it in was full of excitement.
"It’s the biggest I’ve ever caught and the biggest that I know of."
He said he cut the salmon into four large pieces and gave them to four "less fortunate" families for their Christmas dinner.
"Then I went out on Christmas morning at 5.30am and I caught an eight pounder [3.6kg] salmon.
"Most of the ones I’ve heard about being caught are in the 12-13 pound weight, which would be a 3-year-old salmon."
Despite the large salmon being caught, there were few being caught, he said.
"I don’t think there’s very good salmon fishing out in the harbour at the moment.
"The fish have not returned. Normally you get a run before Christmas, and after Christmas, around January, February or March, you get a second one which goes up the Leith to breed."
The salmon catch in the harbour at the moment was virtually zero.
"The two I got, I have no idea where they came from."
He said it was not just an issue in Otago Harbour.
He had heard reports of salmon failing to return to rivers along much of the east coast of the South Island.
"Up in the upper reaches of Christchurch, the Rangitata, the Rakaia and rivers like that, as far as know, not a lot of fish returned into their rivers either."
Fish & Game Otago ranger Steve Dixon said each season was different.
"It’s the big unknown. When they leave the creeks and go out to sea to grow, we just don’t know what happens to them."
He said it depended on what sort of predators were out there, what sort of food was out there, and what the ocean currents were like.
"That determines whether the fish come in again or they survive out at sea.
"Also, at the heads, you’ve got growing numbers of seals that love to eat salmon. That could be a big factor as well."
He said another factor was the warm weather.
"Salmon don’t like warm water and if the harbour is 19degC to 20degC like it has been in the past, you won’t get salmon coming in until that water temperature drops.
"I haven’t heard of big numbers of fish being caught, but the odd one is being caught."
Mr Dixon said there was still hope the salmon would run this season, but it was likely to be in March or April when the water was cooler.
