Daniel Jack is a keen trout fisherman, but not a catch-and-release man.
“Bang ’em on the head and put them in the smoker,” he encourages anyone who asks. Trout and other introduced sports fish are his sworn enemy—voracious predators that ravage the native fish he’s charged with protecting.
Jack is at the wheel of a Department of Conservation Hilux, bouncing up the bed of North Otago’s Kauru River—one of the many frontlines he patrols in his job as a DOC field ranger. The Kauru’s silky waters tumble out of the snow-encrusted Kakanui Range, everything sparkling and fresh on this bright winter’s morning.
We pull up next to a riffle where Jack rigs up his electric fishing machine. As he sweeps its wand across algae-slimed boulders, a pulse of electricity stuns fish and invertebrates into a temporary torpor, causing them to drift into a waiting net. It’s like an X-ray device, in a few sweeps revealing the hidden and surprisingly busy ecological structure of the stream.
Most of the fish are Canterbury galaxias—no more than 60 millimetres in length, their tiny pectoral fins almost as translucent as the water itself. Another sweep flushes a writhing longfin eel from the mimulus weeds, along with a small brown trout. The fish go into a bucket, which by now is also crawling with segmented worms, alien-like Dobsonflies and stonefly nymphs.
Finally, we land the fish Jack is most keen to show me. Well, ‘land’ is probably an overstatement—it’s about half the length of an index finger and as thin as a noodle. The dark-grey speckles along its back mimic grains in the sedimentary cobbles.
It’s a lowland longjaw galaxias, a fish evolved to inhabit the rubble of New Zealand’s decaying mountains—its slender form allowing it to burrow deep into the pebbles in order to hide from predators and say its eggs. Jack points out the protruding jaw that gives it its name. “Only a mother could love them,” he laughs.
This species is found only in the Kauru and a handful of tributaries of the Waitaki. With such a confined distribution, it’s perhaps not surprising that these little ‘jaws’, as they are affectionately known, are in critical danger of extinction. This tiny galaxiid is New Zealand’s rarest native fish.
At the other end of the country, night falls across Donny Park in Hamilton, a narrow crevice of regenerating bush wedged between sprawling suburbia and the Waikato River. The Bankwood Stream rises to flood its gully, where unseen in the rushing murk, a female giant kōkopu manoeuvres into position to lay her eggs—tens of thousands of them—in the submerged grass.
As the water recedes, the fertilised eggs are left behind to mature in the moist vegetation. When they hatch in about four weeks’ time, the tiny larvae will be washed out to sea, where for several months they’ll grow and develop. Those juveniles that survive the ocean’s gauntlet will return upstream in huge schools known as whitebait.
Five of New Zealand’s 30 galaxiid species have this marine stage, called diadromy, as part of their life cycle. It’s a risky strategy, requiring plenty of undisturbed stream-side habitat, something that in our highly modified landscape is now in short supply.
And then there are the waiting nets, set along the riverbanks by hundreds of whitebait fisherman. For some, it’s a traditional recreational practice that feeds family and friends; for others the run is a chance to make a quick dollar. Whitebait are not included in the Quota Management System, so there’s no limit on the amount that can be caught.
The bulk of the whitebait catch is comprised of īnanga, which breed only once in their short lives, laying their eggs in estuaries and river mouths. Also included are the juveniles of kōaro and three species of kōkopu.
Kōaro, which have an extraordinary ability to climb vertical waterfalls, penetrate deep inland and in places have become landlocked, substituting lakes for the ocean. In Lake Taupō, landlocked kōaro once formed an important food source for local Māori, before the introduction of trout dramatically reduced their population there.
Banded, shortjaw and giant kōkopu, all of which are endemic to New Zealand, tend to be found nearer the coast and can live for more than a decade. Banded kōkopu are often found in small, overgrown streams, where they have been observed leaping out of the water to snatch insects off the bank, while giant kōkopu—which can grow to more than 40 centimetres—haunt slow-moving pools and lake edges. Shortjaw kōkopu seem to prefer faster-flowing streams, although as with all native fish species, it’s impossible to know how common or widespread they were before the arrival of introduced predators.
Until 2013, no one had ever recorded a giant kōkopu breeding site. That year, NIWA scientist Paul Franklin and his team discovered large numbers of these fish living in Bankwood Stream, not far from their Hamilton offices. They set out to solve this lingering mystery.
“It was a case of spending a lot of time on hands and knees searching the places they were most likely to lay their eggs,” Franklin tells me.
The search eventually paid off when he and his team found kōkopu eggs deposited on the high-water mark in the aftermath of a storm. The presence of a breeding site for the world’s largest galaxiid, in the middle of a densely populated urban environment, was astonishing.
“These species are nocturnal, so people just don’t see them,” says Franklin. “That’s one of the biggest difficulties in getting people to engage with them. Most don’t know even they’re adult whitebait and that they grow that big.”
Named for the starry flecks of gold that spangle their markings, Galaxiidae are found throughout the southern hemisphere. It’s thought the ancestors of New Zealand’s galaxiids arrived across the ocean from either Antarctica or Australia, pushing into streams and rivers as the country re-emerged from the sea 22 million years ago.
While it’s the migratory species that New Zealanders are most familiar with (fried and sandwiched between two pieces of white bread), most of our galaxiids have actually abandoned the marine phase of their life cycle and evolved to breed in inland waterways.
These non-migratory fish are probably descended from just a few diadromous ancestors, sea-going galaxiids such as kōaro that became landlocked. Once isolated from their close relatives, these fish eventually evolved to become new species.
As the land contorted under the pressure of clashing tectonic plates, the broken landscape of the newly formed Southern Alps drove speciation even further, confining fish populations in steep-sided gullies and in the huge rivers that now spilled out of the mountains. Today, scientists can read the genes of these fish and make inferences about the changing landscape they inhabit.
Perhaps as the starting point for this radiation, Otago is now a hotspot for non-migratory galaxiids, home to no fewer than 11 species.
In order to get to know some of them, I accompany Daniel Jack into the hills behind Lawrence, a large catchment that provides Dunedin with its water supply. Leaving the sealed road, we wind through green pastures chequered by pine plantations and fields of crops. Only the snowy brow of the Lammermoor Range in the distance hints at the wildness that once existed here.
“Over there,” Jack indicates with a sweep of his hand, “you’ve got Eldon’s galaxias and Dusky galaxias. In this stream below us it’s Clutha flatheads.”
There are fish here that inhabit just a few streams. One, the Teviot flathead galaxias, has a distribution of less than half a hectare.
“I’ve been doing this job for 10 years and I still get perplexed,” Jack reassures me. “It doesn’t make a difference when it comes to managing them, it’s just a matter of stopping the trout from eating them and the diggers from digging them up.”
New Zealand’s galaxiids evolved to fit a forested landscape. They need riverbank vegetation to shade the water, keeping it cool and suppressing algal growth, and also to provide refuge for spawning. But farming all the way to the stream edge leaves long stretches of water uninhabitable, while disturbances to gravel beds destroy breeding habitat for the fish.
All of these things are evident as we pass through the Otago hill country, but there are success stories, too—Jack points out areas where farmers have taken it upon themselves to fence off stream gullies, allowing vegetation to dominate. Even gorse, that infamous scourge of the New Zealand rural landscape, is a friend in Jack’s eyes. It provides a nursery for native plants to regenerate and, where it encroaches on river edges, habitat for native fish.
We stop at a stream near Lake Mahinerangi, where the electric fishing machine soon flushes out a few kōaro (Galaxias brevipinnis), each about 15 centimetres long.
“Brevs,” Jack tells me, with a certain resignation, “get everywhere.”
While themselves at risk and declining in number, kōaro predate the larvae of smaller galaxiids, and in doing so may have been a driving force in the speciation of inland galaxiids by excluding them from lakes and forcing them into isolation in the smaller streams that fed those lakes.
As Jack moves the electric wand along the bank, there’s a surge as a fully grown brown trout tumbles out of the weeds. Jack hauls it out to measure and weigh it before returning it alive—it’s over three kilograms. It’s not hard to see the ecological imbalance trout have caused. Once, kōaro were at the top of the food chain here, but no longer.
“Trout will eat anything they can fit in their mouths,” Jack tells me.
Although we are really only just getting to know our diverse suite of galaxiid species, we are in danger of losing some of them. Most galaxiid species in New Zealand are declining in number, at risk, or critically endangered by habitat loss, water degradation and fishing.
Whitebait were once so plentiful they were used for garden fertiliser, but those sorts of catches are a thing of the distant past now.
Waikato Regional Council freshwater scientist Bruno David spends much of his time trying to mitigate the damage—including building ‘fish hotels’ and using innovations such as rope ladders to assist in their migrations.
His job is not helped by a paradoxical legal situation which offers hefty fines or prison time to anyone catching a trout or salmon out of season, but provides almost no protection for native species. (Only one native freshwater fish is protected in New Zealand—the grayling. It was given this status in 1983, half a century after it went extinct.)
“I’ve never seen anything like this, anywhere in the world. It’s ridiculous,” David tells me. In a regulatory sense it creates massive headaches for us. I could go out to the lowland longjaw site in the Kauru and kill every one of those fish and there would be no repercussions.
“I’m not against people whitebaiting, but why should people be able to sell and make money off our native fish when they’re not controlled through the quota management system?
“We’ve got fish with the same threat ranking as kiwi. But can you imagine the outcry if someone went out and harvested kiwi and started barbecuing them?”
Self-described ‘native fish geek’, Stella McQueen, is the author of A Photographic Guide to Freshwater Fishes of New Zealand. “It’s the habitat degradation that’s the real big deal for whitebait,” she tells me. “The whitebaiting is speeding up the decline rather than causing it. They will decline to extinction if we do nothing. It’ll just happen a bit faster if we fish out all the babies.”
It’s landowners who can do the most to protect native fish species, and many around the country are finding that fencing off and revegetating waterways not only has minimal impact on farming activities but can actually add to the aesthetic value of their properties.
St Andrews is not much more than a bend in State Highway One, a town adrift on a sea of irrigated farmland. As the photographer and I pull into the town’s little school, I notice a new water bore being drilled in a paddock across the road, one more to add to the thousands that already puncture the Canterbury Plains.
I pull out McQueen’s fish-identification book and skim the section on Canterbury mudfish, the galaxiid species I have come to St Andrews to see. “Original wetland habitats no longer exist,” it tells me.
New Zealand’s four species of mudfish are the black sheep of the Galaxiidae family. Not for them the fast-flowing, clear waters of the upland streams or the rich bounty of the oceans. As their name suggests, they are at home in bogs and swamps, where they are able to survive dry spells by slowing their metabolic rate and going into a kind of hibernation in the mud.
It’s grim to think that these plains, more than 12,000 square kilometres of sprawling alluvial outwash, can no longer accommodate this tiny fish in its natural habitat. Instead, the Canterbury mudfish is largely restricted to irrigation and drainage ditches.
Ironically, the current farming trend towards water articulated through pipes poses a further threat to mudfish as their artificial water race habitats are being filled in.
“When people want to restore habitat, they don’t think about restoring a drain because it’s man-made,” McQueen tells me. “But in places like Canterbury, where it’s been so wildly changed, you need to start thinking like they do in England, where the habitat that’s left for the wildlife is hedgerows and shelter belts.
“Over there, if you cut down your hedgerow without permission, there will be a massive outcry. We need to start treating what’s left in Canterbury, which is manmade, as if it was as valuable as virgin forest.”
Assisted by a conservation group called Working Waters Trust, pupils at the St Andrews school have helped to restore part of a neighbouring farmer’s paddock to be suitable habitat for mudfish.
Following the students out to the site, a patch of nondescript swamp just a few hundred metres from the roar of State Highway One, I fall in step with 11-year-old Sam Gee, the son of a local farm manager. “Me and Dad used to shoot ducks just over there,” he tells me, “and we had no idea these fish were here.”
I watch the children haul a trap set the night before out of one of the ponds. (Marmite is the preferred bait.) It contains a squirming pile of dark-coloured mudfish.
Sam pulls one of the bigger ones out of the trap and lays it across his hand to show me. “This one’s about 10 years old,” he explains with the pragmatic animal sense of a born stockman. “So it’s probably been breeding for about five years.”
Principal Steve Fennessy can’t overstate the enthusiasm with which his pupils have embraced the project. “It’s a classroom without a roof,” he tells me. “A number have gone and got traps and taken them back to their own places to see if [mudfish] are there. So it’s really linking them to their environment.”
A new chapter in the galaxiid story is being written at the Mahurangi Technical Institute in Warkworth, where researchers have ‘closed the cycle’ for giant kōkopu, meaning the fish can now be bred in captivity.
It’s an operation that grew out of an idea to restock wild streams with captive-reared galaxiids. Ten years later, the institute has developed the technique to the point where commercial farming of kōkopu for whitebait has become a reality.
Mahurangi has formed a partnership with a private venture, Premium Whitebait, and market trials will take place later this year. I ask Paul Decker, aquaculture manager at Mahurangi, about the challenges the institute has faced getting to this stage.
“Where do you start?” he answers after a weighty pause. “There was no data because no one had done it before. We had to work out what temperatures to keep them at and what to feed them. Whitebait require good-quality water, more than most species of fish, which indicates why their environments have been damaged, because they don’t like sediment in the water.”
For Decker, farming is the only logical next step in supplying New Zealand’s demand for whitebait. “I support whitebait recreational harvest—I think it’s part of being a New Zealander. What I object to is how much commercial activity that’s turned into. It’s not a sustainable harvest that can go on forever, so the only way the consumer can fill the hole is by farming them.”
It’s a project that raises intriguing philosophical questions. If, as Decker is convinced, there are direct conservation benefits to farming galaxiids, could such an approach also be applied to other native species? Will commercially farmed weka, kiwi or kererū also find a place on supermarket shelves in the future?
Regardless of the economic worth of whitebait, or the desire to fish for them recreationally, there is a conservation imperative here that can’t logically be ignored—galaxiids are just as much a part of our natural heritage as any of our iconic birds, mammals and reptiles and therefore deserve equal protection.
“A lot of them are found only in New Zealand,” says NIWA’s Paul Franklin. “We have a unique responsibility to protect these species, because if we don’t, they’re gone.”