In brief: Plenty more fish in our seas

Dr Malcolm Francis has been diving for 40 years, but that doesn’t mean he’s seen it all. In fact, just last month he spotted two rare fish in the same dive, right off his local beach.

“I saw a pygmy sleeper. They’re only four centimetres long, and practically transparent, so they blend in beautifully with the background. Then I saw a banded weedfish, and got some good photographs of it. You think you know the Wellington south coast pretty well, but it still holds some surprises.”

It’s just that sort of revelation that prompted Francis to spend a year of his spare time writing the fourth edition of his popular guide, Coastal Fishes of New Zealand. As the oceans warm, more and more tropical species are venturing into New Zealand waters and, says Francis, there are many more divers out there nowadays to spot them. “And they’re more savvy: they know what’s new to the region. What’s more, many now carry underwater cameras, where once may have been spearguns.

“In the old days, it was all about hunting and killing,” he says. “Nowadays, more people hunt fish with a camera.” Which means that, rather than gloomy studies of dead museum specimens, we now have vibrant photos of living fish, and divers are always sending them to Francis. The upshot is that the fourth edition now boasts 275 colour photographs (though 70 per cent are still Francis’) many of highly cryptic species formerly either poorly photographed or not at all. “Divers are much more observant these days," he says, "I might get as many as ten emails a year describing either new or interesting records."

It’s been 12 years since the third edition and, in that time, 49 new species have been added to the pages. Better taxonomic understanding and techniques have seen some fish previously regarded as a single variable species re-classified as two. Francis says divers nowadays aren’t content simply to know what they’re looking at: they want to know more about how a fish lives its life: where it’s found, its breeding biology, its behaviour.

And yes, there are still a couple in his own book that Francis hasn’t seen, but, if he has a favourite, it might be the John Dory. Most of us have only seen it as fillets, but Francis says it’s beautifully adapted as an open-water predator of smaller fish. “They have a very deep, very narrow body, which makes them difficult to spot when they’re approaching head-on. Then they shoot out that huge, extensible jaw and engulf their prey.”

If more of us put on a mask and joined fish in their natural habitat, he says, we might regard them as something more than just dinner. “There are lots of characters in the sea. Spotties, for instance – they’re so common everywhere, and most people know them, but they probably don’t know that they all start life as females, then a few change into males at three or four years of age.”

So is there a fifth edition in him? Most certainly, although he says it might be an electronic publication that people can consult on their phones or tablets.

Coastal Fishes of New Zealand introduces some 90 per cent of the species you might meet around our coast. It is available from the publishers, Craig Potton Publishing, and at bookstores everywhere.

Coastal Fishes of New Zealand

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Principal Scientist - Fisheries