The first thing we notice, aboard a yacht in the Bay of Islands, is the vast sky. It has an outback quality to it, deep and seemingly infinite above the dark-blue Pacific Ocean.

The invasive seaweed caulerpa has been found in a new location in the Bay of Islands, sparking fears it could spread quickly through boating hubs around Paihia and Russell.

Curved like a smile across the North Island’s east coast, the Bay of Plenty and the string of towns threading its white-sand shorelines is a popular destination for New Zealanders, especially in ...