Dive destination Kermadec Islands - once is never enough

The reason the Kermadecs exist at all is due to their being on the collision zone of two of the Earth’s tectonic plates, the Pacific and Australian.

With a trench some 10 km deep adjacent to a highly active ridge, this is the most linear, fastest converging, and most seismically active subduction boundary on Earth. Consequently, it also has the highest density of volcanoes: around 600 submarine volcanoes, and of course islands along the chain. The Kermadecs themselves consist of four groups of islands stretching across 240 km of ocean.

Active volcanoes

This active volcanic region has had its influence on attempts at human habitation here too, in particular on the largest island, Raoul. The threat of a wanton earthquake or eruption is never far away, and it has given would be settlers desperate, sometimes fatal, challenges to living here. Still, the allure of a Robison Crusoe-type existence has enticed several people to try and settle over recent history, usually though not for long.

The ‘King of the Kermadecs,’ Thomas Bell, with his family of nine, managed a 30-year residence on Raoul, working sheep and crops, both to subsist and to sell back to the mainland. Prior to that, evidence suggests Polynesian navigators visited and possibly settled on the islands for a time about 700 years ago

Reserved

By the 20th century, the natural significance of the islands was starting to be appreciated, with its unique floral composition, and huge numbers of seabird colonies. By 1934, all the crown land was gazetted for a Flora and Fauna Reserve, with the remaining private land on Raoul obtained by the government and added to the Reserve in 1992.
The land under the sea has also been protected, becoming New Zealand’s third, and still largest, marine reserve in 1990. There’s a lot to protect. In the desert latitudes, the Kermadecs provide a surprising hotspot of flora and fauna.

Underwater

And diving is why we are here! On first appearances, the reefs appear relatively barren. Absent are the lush kelp forests of temperate coasts, and missing too are the sprawling coral reefs of the tropics. Nevertheless it’s quickly apparent that most surfaces of boulder or bedrock are covered with a blend of delicate or turfing algae, and soft and hard corals.

Fish fascinators

This fascinating mixture of tropical and temperate is multiplied by the fish life. Of the 175 or so coastal fish species currently known to live here, 42% are considered tropical, 45% subtropical, and 12% of temperate origin, showing the mixed nature of their origins. Fishes we seldom encounter in New Zealand thrive here in abundance; the likes of yellow-banded perch, gold-ribbon grouper, and painted moki.

Also, given the lack of kelp, there are a surprising number of herbivorous fishes, including drummers, marblefish and Parma anglefishes. Here they are more diverse in their diet, relying more on plankton, and it is not uncommon to see large schools of drummer feeding on salps in the top couple of metres of the water column.

The mobile invertebrates are chiefly tropical: crown-of-thorns starfish, tropical urchins, exquisite crustaceans and gastropods. Perhaps the most iconic are the giant limpets, endemic to the islands, and dominating the shallow surge zone.

However due to its isolation, and compared with other places, the knowledge of this underwater world is relatively low. Even from our few days there, between us we recorded at least two fish species that we hadn’t encountered in New Zealand before.

Predators

Two large predators patrol the reefs. The Galapagos sharks are very common, a great sign of a healthy ecosystem, and they are our near-constant, yet distant, companions on dives. As dusk approaches each day, we find their curiosity increasing. Several close encounters ensue! Fortunately, most are less than a couple of metres, and as I consider there to be a basic size hierarchy with sharks, so as long as I am longer than them, I’m happy!

The other large fish predator we encounter is the charismatic spotted black grouper. The Kermadecs are the last bastion of healthy populations of this species which reach nearly two metres long! Being long lived and easy to catch, they are vulnerable to overfishing, irrespective of the marine reserve status, and they are fully protected throughout New Zealand, in fact one of only two species of bony fish in New Zealand that are. But, here there is megafauna even larger than either sharks or the grouper.

Whales

Sperm, right, and humpback whales traditionally pass by the Kermadecs twice a year on their annual migrations. In the 19th century they attracted whalers from around the globe. The Kermadecs find themselves in the logbooks of many a whaling ship, along with hundreds of barrels of whale oil, in particular those from the famed whaling haunts New Bedford and Nantucket in the US.

Since the cessation of whaling, humpbacks have started visiting the Kermadecs in numbers once more. Each spring scores of them, many with calves in tow, stop to rest and socialise around Raoul for a few weeks on their way south to feeding grounds in Antarctica. We anchored at the islands for a week and found it hard to tire of the constant breaching and singing from these gentle leviathans. Their vocalisations certainly added a unique sensation to the night dives we undertook.

Keen sense of the remote

One week at the Kermadecs Islands was never going to be enough. This rugged, swell-battered, volcanically active group of rocks really kindles a sense of the remote, a feeling not many places left on Earth can. And with the fascinating blend of human and natural history it was easy to be truly captivated both above and below the water.
Of the many feelings elicited over our seven adventurous days at this special place, the most profound perhaps was a sense of appreciation. Gratitude too, that there are still wild places like this we can visit, wild places like this left for nature, without human interference.

With thoughts like these and a firm easterly filling our sails, against the silhouette of Raoul sinking below the horizon, we set off on our four-day passage back to the mainland.