Coromandel Gold

By Tony Breen

When most divers talk about New Zealand’s top dive sites they’re probably referring to the Poor Knights islands. What a lot of divers don’t know is that there is equally good diving off the Coromandel peninsula.

The Aldermen islands are a cluster of five main islands and numerous pinnacles approximately 24 kilometres from the costal town of Tairua. The Aldermens are a nature reserve, covered with native coastal forestry. They are pest free and home to native tuatara and robust skink. Access to land on these islands is by permit only.

The main reason for my three day trip was to obtain research data for a project I’m doing at the Bay of Plenty Polytech, marine studies: The effects of sea urchins (kina) on marine algae growth.


The coastal reefs are affected by the large populations of kina which results in kina barrens – areas of no seaweed or algae cover. At the Aldermens the population of kina is small, they are not creating the same effects as on the coast – why?

The first day was overcast so the visibility wasn’t amazing. The vibrant colours of the lush algae forests don’t have quite the same glow when it’s overcast. We managed five dives between three teams before the weather packed in.

The second day we hugged the coast and explored northwards from Tairua to Hot Water beach.

On day three the Aldermens decided they were going to turn it on for us. The first dive was on a pinnacle not far from Ruamahuaiti Island (the southernmost island). We anchored in 20 metres and were able to clearly make out two spot demoiselles hovering on the sand below.

The visibility was good and I could make out a patch of Ecklonia seaweed on a rock more than 30 metres below.

During our dive we spotted sponges, nudibranchs and conger eels. I was pleased to see only one tiny kina on this entire pinnacle.


After I returned to the boat a couple of experienced divers surfaced after exploring Shark Alley. They were absolutely ecstatic! I’ll have to check it out next time I visit the islands. The surveys were supposed to start in around 16 metres of water however the third site saw us in eight. We elected to drop back in anyway and obtain what data we could. I’m glad I did. During the entire dive we were followed by a massive variety of fish species. Even the schools of silver drummer weren’t perturbed by our presence. The large patches of Caulerpa sp. (sea rimu) and Pterocladia sp (both algae) changed the water’s hues between pink and luminous green, just stunning!

After having an enjoyable time playing with some Sandagers wrasse we swam back to the anchor line and headed for the surface. On the way we bumped into a school of squid hovering mid water. A great way to finish off our dive! My research is on-going and I’ll need to return to these beautiful islands to continue my studies – someone has do it!!


Every diver needs to dive these islands. There are fewer divers in the water than at the Poor Knights and there is just as much to see.

The Aldermens are serviced by the same current as the Poor Knights so enjoy the same visibility on a good day.

scroll to top