Absolutely Steve,
The Barrier locals report seeing it there 5 years ago, they just didn't know what it was. Didn't sound like it had made any noticeable impact over that time in terms of the ecosystem collapsing. It was only 'discovered' there because a biologist was on holiday and put it on iNaturist, of which is posted to 6,000 times before (i.e. its his thing).
It was only 'discovered' in Rawhiti because Iwi individuals started doing patrols for it. By the shear number of locations found, it has clearly been there for a while. It wasn't transported on a single boat anchor in March