There are potential positives to Caulerpa:
We have a problem with kina barrens right? If kina eat this stuff they go sterile. So, it may well create suitable habitat for nursery fish, and, tadaa, re-balance the Hauraki Gulf. Providing the caulerpa doesn't smother other food sources, this could work really well. The photos I've seen show the eclonia still growning, with the caulerpa around the base. Could just work.
The other thing is the carbon sequestered growing this stuff. Carbon sequestered in the oceans is enough to reverse climate change. There are many projects underway to gro