What’s going on with the reefs?
Head out to your favourite fishing spot, and before you sink a line, grab a mask and have a gander over the side. There’s a 50:50 chance you’re going to see something that looks a bit like this—go ahead, grab it, have a look around…
This is Nordic Reef just outside of Leigh Harbour. Or at least it was. Nordic Reef was once one of the most productive rocky reef habitats in Hauraki Gulf. It was cloaked in kelp and absolutely heaving with crays, big snapper, reef fish and an epicentre for work-ups of kahawai and kingis. Today you’ll find a few reef fish and about a million kina. (Don’t even bother with the kina though, they’re mangey things without any roe because they’re half-starved.)
How did it get like this?
Well, it took a while. With a century of heavy fishing on this coast, there are few crays and big snapper left. Without predators, kina populations explode and they mow down the kelp forest like diggers driving through a rainforest.
It’s a process called trophic cascade. Imagine removing the columns of a skyscraper one-by-one until the ceiling collapses on to the floor below, which collapses on to the floor below that, all the way down until there’s nothing but rubble.
A barren on north side of Tiri, with remnant kelp forest. Arie Spyksma/New Zealand Geographic
This might sound dramatic, but it’s exactly what is happening across half of the reefs in the Hauraki Gulf—as far out as the Mokes. Northland is the same. Bay of Plenty is heading that way too.
There are only two ways to fix it—remove all the kina and keep removing them every six months, or protect it from fishing so that predators return and do the job for you. (In areas like Mimiwhangata where they have tried protecting against commercial catch but allowing recreational catch the fishing pressure became so great that fish abundance actually decreased and the reefs are still barren, so that doesn’t work.)
We can have an abundant and productive gulf and fish it too, but we need to reduce the take to avoid total collapse.
