Hitting bookshop shelves like a 10.9kg brick is the fascinating four-volume compendium The Fishes of New Zealand. It is exactly the resource that co-author and ichthyophile Andrew Stewart wanted as a child, he tells Bruce Munro.
Andrew Stewart is leafing through the culmination of 20 years of his working life. And he is smiling.
In his hands is volume three of The Fishes of New Zealand. Next to him sit a further three tomes. Combined, it is a 1748-page, full-colour, four-volume set, which for the first time catalogues and describes in one publication all 1262 known species of fish in New Zealand waters.
''Ah, yes. Murray's humpback anglerfish,'' Mr Stewart says, looking at a photograph of what appears to be an enormous swimming eyeball with fins.
''I remember that. It was taken on the Norfanz expedition; a four-week multinational research expedition that went up the Norfolk Ridge and down the Lord Howe [Rise].
''We were sampling in deep water. And that was the first time we caught that species and recognised it as that species.
''We had taken a digital photo suite on board with us. So the fish were coming up ... being registered and put on the photo table ... They couldn't have been fresher.''
It was late autumn 2003, midway through what would prove to be a 20-year international effort to gather and produce information on all the known species of fish in New Zealand's four million square kilometre exclusive economic zone.
The project was a government-funded collaboration between the Museum of New Zealand Te Papa Tongarewa and the Foundation for Research, Science and Technology, with help from the National Institute of Water and Atmospheric Research.
In all, contributions were made by 44 ichthyologists, from 27 organisations in nine countries, including Mr Stewart, collections manager of the ever-expanding National Fish Collection housed at Te Papa, in Wellington.
''It's quite stunning to see it in its final form ... We are really, really pleased,'' Mr Stewart says of the hardback book set published by Te Papa Press.
''This is the most comprehensive book that has ever been published on New Zealand fish. There are 140 species in there that have never before been recorded from the New Zealand region.''
Not every living thing found in our rivers, lakes and oceans has made its way into the collection and the books. The word ''fish'' has a specific meaning, Mr Stewart says.
''It's a ... term we give to an organism that has a thickening rod down the backbone ... has gills all its life, has limbs when present in the shape of fins and lives in the water.''
At the same time, some things that are not technically fish were allowed to swim on to the pages.
Humans, Mr Stewart says, are more closely related to fish than are the hagfish, lancelets, sharks and rays which are in the books.
''Are they really fish? Well, we've been calling them fish for the past 250 years, so let's keep on with it.''
There is another definition of fish: those subjects of the animal kingdom that are Mr Stewart's abiding passion.
By the age of 3, Mr Stewart, who was living in Dunedin, was already a confirmed ichthyophile.
On holiday with his grandmother, he was taken to a large toy shop and told he could have any one item on offer. He chose a fluorescent green plastic fish. His horrified grandmother bought him the fish but also bought a fire truck of her choosing.
''Well, the fire truck gathered dust, but the fish was christened Sammy the Shark and was finally retired when I was quite a bit older,'' he recalls.
Decades later, the shape, colour and nature of fish continue to produce in him a visceral response.
''The love affair hasn't diminished at all. I still think they are absolutely fascinating.
''There is something elusive about them ... I think it is the same sort of thing that leads to some people developing a fascination for birds.''
Some fish have discernible personalities, he adds. Take, for example, the olive rockfish, which can be found in most rock pools along the New Zealand coastline.
''If you keep them in an aquarium, they will very quickly learn who comes to feed them ... If they know they are not in any danger, they are quite happy for you to pick them up.
''And blue cod, they have personality in spades ... They can become very friendly and inquisitive.''
• These books - with their photos, maps, names, classifications and descriptions of each species of fish, from the shy Abbot's moray eel to the mohawk-spined zebra lionfish - are exactly the absorbing and comprehensive resource Mr Stewart wanted as a child.
He hopes it will help others grasp what he grew up discovering.
''That there are so many more than just ... edible ones and ones I throw back ... The incredible diversity in colour and the differences there are in body shape. All of these are to answer the three really big questions in life. How do I find a meal?
"How do I avoid becoming someone else's meal? And, how do I find a mate?''Fish have come up with this incredible diversity of answers to those three questions.''
As terrestrial mammals, humans tend to ignore the importance of the oceans, Mr Stewart says.
''If I was to come as a visitor from outer space, and say to you `Show me the dominant habitat on your planet', you would have to take me to the deep ocean, 1000m and deeper.
''There is more habitat, more space where life exists, that is deep ocean than all the rest of the planet combined.
''And this habitat is what governs us, even though we don't see it or appreciate it very much. We are aware of deforestation, of soil erosion and issues around freshwater, and so we should be. I think we should also be acutely aware that we are held up by this vast [ocean] habitat.
''At the poles, cold oxygenated water sinks down and travels across the abyssal plains, bringing oxygen to the depths and keeping them alive. Then it warms up and brings nutrients to the surface that provide food for the phytoplankton, which starts the whole food chain. Most of the oxygen we breathe is actually generated by phytoplankton in the ocean.
''But none of it is particularly obvious to us. We tend to treat the ocean as something we can just dump stuff in, that will always be there and will never change. We need to have a different view of the ocean and the animals that live in it.''
He hopes The Fishes of New Zealand will contribute to that understanding.
The books have an added poignancy for Mr Stewart. They are dedicated to his wife Liz, who died in June of a brain tumour.
''A lot of the co-authors were friends of ours and they would come up to our place for meals.
''I can see and hear her in my mind's eye. If she knew, 'Honey we've dedicated the book to you', she would laugh and laugh and roll her eyes and go 'Oh, please', and I would never be allowed to forget it.''
The four volumes are an end, but they also mark a new beginning, Mr Stewart says.
Although it is in one sense an authoritative compendium of New Zealand's fish, there is still more to learn.
Much is still unknown about New Zealand's inshore fish fauna. Our patch of the 2000m to 6000m-deep abyssal plain is ''virtually untouched''.
And Mr Stewart would ''love to know'' what might be found in the unexplored Puysegur Trench, south of Fiordland.
''This has put a line in the sand. This is what everyone can know, as of November 2015. 'But wait there's more'; that is the subtitle.''
New Zealand's monsters of the deep
FASCINATING FISHY FACTS
New Zealand's 1262 fish species come in all shapes, colours and sizes. Their habitats, defences and feeding practices are equally varied. One even has its own Facebook page. Here's a wee taste of our unusual fish.
• Bearded anglers live at depths of 150m to more than 1000m, where there is no light. To confuse and attract prey, female bearded anglers have two sets of bioluminescent lights. The lure atop the female's head houses colonies of light-producing bacteria, while the seaweed-like beard beneath its chin is lit by its own bioluminescent chemicals. The male bearded angler is much smaller, and parasitic. It latches on to a female with its teeth and eventually fuses with it, losing its eyes and all internal organs except the testes.
• Mr Blobby became an instant hit when his image was put online. With a body that is more gelatinous than fleshy, the deep-sea blobfish floats above the ocean floor. In 2003, this blobfish was caught and photographed northwest of New Zealand. The image went viral when it was uploaded to the Norfanz scientific expedition website. Since then, he has been voted the world's ugliest animal, had his own Facebook page set up and made an appearance in sci-fi comedy Men In Black 3.
• Striped anglerfish are members of the world record-holding frogfish family. They can open their jaws, engulf and swallow their prey in an unbeatable 6 milliseconds (0.006 seconds), taking a fish without the rest of its school noticing. To enable it to swallow in one gulp, the striped anglerfish can expand its cheek cavity up to nearly 14 times its original size.
• Hagfish are also known as snotfish. That is because they come equipped with 90 to 200 slime glands from which they can fire large quantities of slime into the mouths of predators. Hagfish slime contains slippery mucins and tightly coiled protein threads. When fired, the mucins absorb water and swell while the threads uncoil, creating a 3-D mesh which chokes the gill cavities of predators. A giant hagfish can potentially produce more than 2000 litres of slime.
