Why did you write Deep New Zealand: Blue Water, Black Abyss?

The deep sea is an exciting topic. It really is the last frontier, the only place on Earth that is still mostly unexplored. And New Zealand's oceanic waters are no exception. Ever since I first went deepwater trawling, back in the 1990s, I'd been fascinated by the strange and entrancing creatures that live there.

A deep-sea lizard fish Photo Source: Peter Batson Click here to view a larger version

And from the publishing point of view, the deep sea was an empty niche in New Zealand's natural history literature. It wasn't hard to persuade my publisher that there was a need for such a book, especially one intended for a popular audience.

What exactly is the deep sea?

If you're a scuba diver, 40 metres is deep. But in the scheme of things that's nothing. The depths we're talking about here are best measured in kilometres. Beyond New Zealand's shallow continental shelf, the ocean floor drops off quickly into the abyss. The average depth of the Pacific is around four kilometres, and the deepest point in New Zealand waters is ten kilometres, at the bottom of the Kermadec Trench.

What's life like in the deep sea?

The abyss is an eerie underworld where everything moves slowly. Fish swim at a snail's pace and crabs move the way toy robots do just before their batteries run out. It's a peaceful sort of place to visit, like a vast undersea rest home.

But don't be deceived by their relaxed appearance - life isn't easy for the animals that live in the abyss. They take things slowly because there is so little food available. All those creatures are pacing themselves, waiting for their next meal to come along. This is why most deep-sea animals grow slowly and live long. And food supply isn't the only problem; they also have to cope with other challenges too - crushing pressures, permanent cold, and complete blackness. All things considered, they do very well.

What's special about New Zealand's deep ocean?

For a start, it's enormous. We have one of the world's largest ocean territories. It covers an area ten times the size of France. Our Exclusive Economic Zone covers more than four million square kilometres, which is great because it gives each New Zealander almost exactly one square kilometre of his or her own.

Second, New Zealand has one of the most diverse seascapes anywhere in the world. Within our jurisdiction are trenches, plateaux, canyons, ridges, rises, basins, hills, channels, active volcanoes, and vast sweeping plains. In fact New Zealand has examples of nearly every seafloor feature known. All Kiwis are proud of our nation's spectacular landscapes, but how many realise that our undersea domain is just as dramatic?

Third, New Zealand has a fantastic cross-section of the world's known deep-sea biodiversity. We deserve our reputation as giant squid capital of the world, but that's just the tip of the iceberg.

Deep-sea squid Photo Source: Peter Batson Click here to view a larger version

With oceans spanning sub-tropical to sub-polar latitudes, the nation possesses a good fraction of the world's known oceanic fauna. Life exists from the ocean's surface layers, down to the bottom of the Kermadec Trench, 10 km down.

What was the most challenging thing about writing the book?

Finding good pictures. I wanted the book to be beautiful, but achieving this wasn't easy. If you're doing a book about New Zealand trees, you go out into the bush with a camera. It's a bit different with the deep sea - access is difficult, if not impossible. I didn't have my own deep-diving submarine or research ship, so I had to cast my net wide. I enlisted the help of two excellent photographers, Kim Westerskov and Craig McVie, and took my own photos whenever the opportunity arose.

I had other help too. Dozens of scientists helped out by providing images of their study animals, others sent me specimens of marine life to use as the basis of artworks. If you read the book's acknowledgments, you will find more than160 people listed; most of them helped out with pictures.

What is it like visiting the abyss in a submarine?

If you ever get a chance to visit the abyss in a submersible, jump at it. The one time I went down there, it was on an American sub called Alvin. We visited undersea hot springs, two-and-a-half kilometres down, on the summit of a mid-ocean ridge off Central America. It was surreal, and there was a real sense of adventure unlike anything I had ever experienced. The feeling of seeing places never before seen by human eyes was indescribable. According to scientists, the bizarre life found among these undersea hot springs is as close to life on another planet as anything we can ever hope to encounter. Looking at the animals we saw on our dive, I'd be inclined to believe them.

It used to be that the only people who visited the abyss were sub pilots and scientists. But there is now a company, Deep Ocean Expeditions, that takes paying passengers on trips into the abyss. Using a pair of Russian Mir submersibles capable of diving to 98 per cent of the world's seafloor, they visit all sorts of incredible places, including hydrothermal vents and the wrecks of the Titanic and Bismarck (visit deepoceanexpeditions.com).

What is your favourite deep-sea creature?

For sheer optimism, it would have to be the black swallower, a small midwater fish of New Zealand's deep oceans. This creature will swim up to a fish two or three times its size, open its toothy mouth, and swallow it whole. Its belly is like a balloon, and it expands to ridiculous proportions to accommodate prey that would, under different circumstances, have happily eaten the fish it was just swallowed by.

The Black Swallower Photo Source: Peter Batson Click here to view a larger version

To learn more about Deep New Zealand, or deep-sea life in general, visit http://www.exploretheabyss.com

Read Dorothy's review of this book