ROSS GIBLIN/STUFF
Longfin eels are only found in New Zealand, and some experts say we're not doing enough to protect them.
It's one of the world's most incredible, yet mysterious, fish species. But years after high-level calls for a moratorium on the commercial exploitation of longfin eels, they continue to be fished and exported live overseas. The species may be on the brink of a critical tipping point, as Charlie Mitchell reports in the first of a two-part series.
You can often find Doris at lunchtime, if you know where to look.
She's usually holding court by the boatsheds, floating in the gentle current of the Avon River, lurching out of the water to snatch food from someone's hand. Doris is long, perhaps a metre, and her meandering fin narrows into an arrow shape at her tail.
At around 60 years old, Doris is in her prime.
At some point – which could be next year, or a few decades from now – it will pour with rain and Doris will leave the comfort of the boatsheds to sail down the river and out to sea; her head will flatten and her eyes will bulge so she can navigate the darkest parts of the ocean, up to a kilometre deep, where she will swim for months, not stopping to eat, until she reaches some mysterious abyss in the Pacific Ocean that no-one has ever found but where every longfin eel starts, and ends, its life.
DAVID WALKER/STUFF
Doris the friendly eel became a popular attraction at the Antigua boatsheds.
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Moments before she dies, Doris will unleash millions of tiny eggs, translucent and flat and shaped like leaves. They will retrace Doris's journey in reverse, returning to New Zealand, a place they've never been, thousands of kilometres away.
How do these larvae know their whakapapa? It's one of many mysteries. It was once thought they passively drifted on ocean currents, but we now know they actively swim; even when blown off course, the larvae find their way to New Zealand, to the same rivers and streams their ancestors lived in. Glass eels have magnetite crystals in their tiny brains, so it may be through a connection to the Earth's magnetic field, but it remains a theory.
It'll take up to a year for them to arrive in New Zealand, where they'll amass at a river mouth and turn into glass eels, tiny and translucent, much like a whitebait.
TONY FOSTER/CC BY-ND 2.0
A longfin eel in a creek.
At this point, if you were to cut one open, you would find a pattern of swirls on its ear bone, each circle representing one day of the tiny eel's life, like the rings of a tree.
As the eel ages, the rings get wider apart, which can be used to estimate how fast they grow. The oldest longfin recorded by science, found in Lake Rotoiti, was 106 years old - by studying the earbones of eels in that lake, it was discovered they grew with incredible caution, reaching full size, on average, at age 93.
When the glass eels become elvers, they will start to make their way upstream, and may get as far as the high country, which can take them decades. Some will remain in the lower reaches of rivers such as the Avon, or in estuaries or coastal lakes, not far from where they arrived.
Wherever they end up, the longfins live out their remaining decades in their chosen length of river, lake, or estuary, until a great rain falls, they turn a shade of silver, and so the magical cycle goes on.
For some longfin eels, life doesn't go that way.
Every year, tens of thousands of longfin eels are caught in fyke nets – a cylindrical, netted bag – and taken to one of a handful of eel processing facilities, where they spend several days in a holding tank.
From there, some will be placed in a polystyrene box, which is lined with plastic, filled with ice and water and sealed with oxygen. The box is put on a plane and will arrive up to 24 hours later in New York, or Seoul, or Beijing, or Brussels – the eels will be unpacked, still alive, and likely kept in a murky tank until a chef decides their time is up.
Every month, more than a thousand eels are shipped live overseas to be eaten, often to countries in which their own eel population has been overfished to near extinction.
The state of the world's wild eel stock is a catalogue of plunder: European eel numbers have collapsed by as much as 99 per cent over the course of several decades; Japanese eel abundance has fallen around 80 per cent, and American eel populations have halved. Reasons for the decline vary, but all include elements of overfishing and habitat loss.
New Zealand's eels have benefited, in part, from being lower on the pecking order. Their lower fat content makes them less attractive to eat, particularly among Japanese diners, who account for much of the world's eel consumption.
It hasn't stopped demand for New Zealand eels, particularly in the context of a massive decline in global supply. They are still sent overseas in their thousands, often alive. It has been illegal to export livestock overseas for slaughter since 2003, and the government is considering banning all live exports of cattle, but neither rule applies to indigenous longfin eels.
If a longfin eel isn't caught in a net, it doesn't mean the danger is over.
The tiny elvers that arrive from the Pacific can climb tall, vertical surfaces, which allows them to scale some dams and other obstacles in their quest upstream.
JOSEPH JOHNSON/STUFF
Niwa's Dr Don Jellyman working in a stream in Christchurch.
Dams often have programmes to catch and move these elvers upstream, so they don't get stuck beneath a dam too big to climb; some have climbing tracks for the elvers, allowing them to summit the dam themselves.
However they get upstream, it leaves them unable to get back.
When an eel decides it's time to head to the Pacific, it will rush down-river during a flood, meeting the dam it scaled long ago from the other direction.
New Zealand dams have small, quick moving turbines, which are incompatible with a large, fast-moving fish. They are effectively giant mincers. Eels that end up in dams are often chopped to pieces; videos of decapitated eels show they continue to writhe for hours. Some will survive the turbines, but with critical injuries to their skulls or their internal organs that result in a slower death.
If it isn't a dam, it could be a pumping station. They have become increasingly common in rivers, and are meant to reduce flooding during heavy rain, the time in which a longfin eel is most likely to migrate. Recent evidence shows these pumps are killing eels en masse, in gruesome ways; they effectively turn the eel's organs into liquid.
The grimness of this death is best understood in the way they are counted; a microphone next to the pump picks up the sound of flesh against machinery, each thump marking another painful death.
KEELAN WALKER/SUPPLIED
Eels in Lake Rotoiti. The oldest recorded longfin eel, which was 106 years old, was found in the lake.
AN EXCEPTIONAL CREATURE, AND A CREATURE OF EXCEPTION
When the world's pre-eminent longfin eel expert first came across the creature he would study for half a century, he was killing them.
Like many young New Zealanders, Don Jellyman made pocket money by killing eels and presenting their tails to the local acclimatisation groups.
The arrival of European colonists proved a rapid change in fortune for the longfin eel, which had been seen differently by Māori.
In a land without mammals, giant longfin tuna (the generic name for eels) were a gift, and a vital food source. You could put one in a pond, and it would survive for months; you could smoke them and save them for tough times. In Māori mythology, taniwha sometimes take the form of an eel, lurking in deep, murky pools, a river's kaitiaki; other times they are menacing, enforcing breaches of tapu.
Europeans, on the other hand, disdained eels. By the mid 20th-century, eels were declared vermin, as they were thought to negatively affect trout stock. The acclimatisation societies put bounties on native eels in the South Island, and dams were designed so eels couldn't get through them. It was later discovered that without eels, trout numbers did indeed increase, but they were much smaller in size. It was thus better to have eels and trout co-existing, meaning the whole extermination campaign was counter-productive.
Jellyman grew to appreciate eels, even when society didn't. Half a century later, well into semi-retirement, he still publishes papers on eels, in his role as emeritus scientist at Niwa.
ANDY JACKSON/STUFF
A friendly eel in New Plymouth's Huatoki Plaza.
One thing is clear about longfin eels, Jellyman says: There aren't as many as there used to be.
"In the Waikato, we'd get a continuous band of glass eels going past a fixed point for a couple of days," he says.
"We don't see that now. We still get migrations that last a few hours, but we don't see those huge migrations."
Like others, Jellyman has struggled to quantify just how many eels there are, and whether the species has stabilised after those initial declines. There is still so much to learn. We don't even know where they come from, which Jellyman calls the "holy grail" of eel research.
It has left cause for concern. One worry is climate change, and how that could change conditions in the ocean patch where eels spawn. For all we know, eels may already be struggling to find each other there, and by the time we know if that's the case, it could be too late.
Another particular concern is the efficiency of eel fishing; unlike typical fisheries, eelers catch eels by luring them to a net, which is remarkably efficient.
Jellyman recently went to a river on the West Coast which had never been fished before. In one night, he caught around 70 per cent of the river's eels. It would take at least a decade for the population to recover from the effect of just one night's fishing.
"Those sorts of things make me very cautious," he says.
"With a species like eels, you have to be very conservative in your management. If there is some sort of ecological tipping point, it may suddenly become apparent, and we may think shivers, we should have seen it coming."
The unique life history of the longfin eel makes it particularly difficult to manage. Unlike most commercially caught fish, it only breeds once, at the end of a life that can be many decades long; an eel may breed at 40 years old, or 100 years old, an element of uncertainty that can't be captured in a typical fisheries model.
Despite these issues, the species (alongside its close relative, the shortfin eel) was from the early 2000s added to the Quota Management System (QMS), the main tool used to regulate fishery stocks.
Under the QMS, each fishery has a total allowable catch (TAC) set every year. It is based on a stock assessment, which usually sets the bottom line at the maximum sustainable yield –effectively the quantity of fish that can be caught without depleting the population.
It's not possible to calculate the maximum sustainable yield for longfin eels. For that reason, they are included on a separate schedule within the Fisheries Act with a dozen other species, which means a stock assessment does not need to be undertaken.
Information about the sustainability of the longfin fishery thus needs to be pieced together from different sources; Those sources have been a matter of long-running dispute.
These matters aside, the commercial fishing of a native species has never sat well with some people.
Longfins are not just native, but endemic, found nowhere else in the world. If New Zealand can't protect them, they will be erased from existence.
They are also in decline, at least officially. Under the Threat Classification System, they're labelled 'at risk-declining', a status they share with the North Island brown kiwi and the blue penguin. It's a couple of steps lower on the conservation rung than the likes of kererū.
Killing a kererū is punishable with a $100,000 fine, or up to a year in prison. Killing a longfin eel – which has a poorer conservation outlook – is rewarded with somewhere between $10 and $20 per eel on the export market.
STEUART LAING/SUPPLIED
An eel migrating to sea on the Banks Peninsula.
For the scientists who study native freshwater fish, the way we treat longfin eels has long defied belief.
"They're like all of our native fish, they're declining and we don't know how much they're declining," says Dr Mike Joy, a freshwater ecologist and environmental researcher at Victoria University of Wellington.
"We, as in freshwater ecologists, know that elver recruitment is way down, and we're seeing them in fewer places.
"I think they're in the s..., and we could do something about it by not commercially harvesting them."
Stella McQueen, an independent freshwater ecologist, has similar concerns. She says by continuing to fish them, and restrict their habitat by developing rivers, we risk repeating the mistakes of the countries we're sending our eels to for consumption.
"I think the commercial harvest of eels is absolutely bizarre," she says.
"There's demand for them because they've [importers] already destroyed their own, and we're simply not learning that if we keep doing these things, you will lose your eel populations."
They are not alone in holding a pessimistic view of the species' long term prospects. Several other freshwater ecologists have questioned the sustainability of the fishery, and over the years, their concerns have fallen on deaf ears.
A pivotal moment for those who want greater protection for eels was the release of a 2013 report by then Parliamentary Commissioner for the Environment (PCE) Dr Jan Wright. She found there was considerable evidence that the species was in trouble, and recommended a moratorium on commercially fishing longfin eels until the sustainability of the fishery could be proven.
The findings were welcomed by freshwater experts, who had raised similar concerns. Among them were Dr Roger Young, who said the report provided "strong evidence that the population is in serious trouble"; Dr Russell Death, who said a moratorium was an "obvious first step," but more drastic measures were needed to save the species; and Dr Gerry Closs, who said the longfin eel was "being managed into extinction by the government agencies responsible for their protection" and not acting on the recommendations would be "willful negligence".
The moratorium, however, did not happen.
One of the PCE's recommendations was to establish an expert panel to assess the quality of the science underpinning the fishery. This was done, but the resulting report didn't clarify matters much.
"We agree that there is a high probability that the longfin eel population has been substantially reduced relative to pristine biomass," the panel concluded.
"However we consider there to be a high level of uncertainty regarding the current stock status."
Critics say it's no surprise the report didn't find much. Its terms of reference precluded it from looking at the Ministry for Primary Industries' past decisions about fisheries management, the QMS itself, local eel management decisions, or the threat classification system.
In any case, it was not the tiebreaker each side of the debate had hoped for. In an update to the PCE's report, following the release of the expert panel's findings, she again urged a moratorium, and again, it did not happen.
Since then, only one significant step has been made. The South Island fishery had long combined shortfin and longfin eels together, meaning eelers could catch one or the other, as long as they stayed within their overall quota.
They are now split, meaning there is a limit on the longfin eel catch.
It was a blow to the commercial eelers, but once again, they managed to stay in business.
Why has this situation persisted, despite the long-held concerns of experts and mana whenua who believe we may be shepherding a native species towards extinction? In part two, published on Monday, July 8, the scientific debate, and the tiny industry that has survived repeated attempts to shut it down.
Sunday Star Times
