That dictionary entry from 1995 doesn't give a dated citation so it doesn't add anything to the other sources quoted here (which are quite likely where they got it).

One person who will have known a lot about early onshore whaling in NZ is the writer Ian Wedde - it's the central historical focus of his novel Symmes Hole written in 1984. He mentions that he got a lot of his background from unpublished manuscripts in the national library in Wellington, things nobody had looked at before. I get the impression he feels he's well and truly through with that but it can't hurt to ask if anyone in Wellington knows him.