Crake said he was surprised to see the 63kg pig so far out into the harbour but killed it with a knife after dragging it into the boat.
Crake said his granddaughter had posted the footage, and reactions had varied from supportive to outraged.
"Some were happy and some were pretty disgusted, they thought we'd drowned it."
Crake said they didn't make the pig suffer during the catch. "There was no cruelty at all."
However, SPCA manager Alan Wilson said Croke's actions were "just not on".
Wilson said "it's an offence we would look into, and we're going to take our time to investigate it."
It's not the first time fishermen have encountered a wild boar outside of its natural habitat.
In July last year two men from Whitianga pulled a boar onto their boat after finding it swimming a few kilometres off the coast of the Coromandel.