They’re joined by a school of mahimahi, a large tropical fish species, which has come to New Zealand following the warm water, and will likely leave again before the end of summer. Most migratory species in this blue zone follow the same inshore-offshore seasonal pattern, including billfish and manta rays.

We are only beginning to understand the natural mechanisms that connect New Zealand’s seas to the world, and yet we are harvesting these seas commercially. There is no catch data on small schooling fish, for instance, yet they are a critical component in the oceanic food web. We are interfering in a system we do not yet understand.