The dams, the science, and the tiny eel industry clinging to life

Friday, 5 July 2019

Longfin eels are only found in New Zealand, and some experts say we're not doing enough to protect them (video first published July 2019).

The commercial longfin eel industry is the smallest it has ever been. And yet, there is still a dispute about the science underpinning the fishery. Charlie Mitchell reports in part two of a series.

For a long time, if you wanted to find giant longfin eels, a good place to look was Lake Otamangakau, near the Tongariro National Park.

The eels were huge because they could never leave. They would grow and grow and grow, and then they would die in the lake, because a dam blocked the only way out.

As they have elsewhere in New Zealand, the dam transformed the ecology of the surrounding rivers and streams, but it took some time for that to become clear. The unusual life history of longfin eels creates a delayed response – the old eels stick around, even if new eels do not arrive. Then, when the old eels die, or leave to spawn, nothing replaces them. They just vanish.

The Tongariro power scheme is within the rohe of Ngāti Hikairo ki Tongariro, a hapū of Ngāti Tūwharetoa. Nationally, it's an important area for longfin eels; it is between the national park and the Whanganui River, both of which have little to no commercial eeling.

Longfin eels in Horokiwi Stream, Pauatahanui.

* Eel could be back in the menu as 'clean' meat

* Shock after discovery that dead eels found in stream were rare and a declining species

Dams such as Karapiro have caused immense damage to longfin eel habitats.

* Revised quotas for eel catches in South Canterbury may put exporters out of business

* Pressure to ban fishing of longfin eels rises, as industry faces upheaval**

The hapū was well aware the eels were disappearing. Lena and John Morgan, of Ngāti Hikairo ki Tongariro, decided to do something about it – they approached the power company, Genesis Energy, on behalf of the hapū and they now work together to transport eels past the dam so they can spawn.

In the six years since the programme started, they've moved around 30 migrating females a year - an indication of how much the population has fallen.

'My husband remembers as a child gathering eels down there and getting 30 in a night, not 30 over an entire season,' Lena Morgan says.

'There's been no recruitment. Before this programme, there was no recruitment going in, and nothing coming out. For 50-odd years, nothing was done, so of course the population dropped.'

The long-term decline of the giant longfin tuna (the generic name for eels) has been a particular affront to Māori, especially those who practice mahinga kai.

While a steady stream of reports commissioned by government agencies has failed to adequately answer, once and for all, whether the species is still declining, reports from hapū such as Ngāti Hikairo ki Tongariro paint a much clearer picture.

Longfin eels can grow more than 2m long and weigh up to 25kg.

The Morgans say it started with the extermination campaigns many decades ago. Then it was the dams, and the commercial fishers, all of which have combined to create impossible odds for a precious taonga.

'They [tuna] have just had no chance right from the beginning,' Lena Morgan says.

Earlier this year, a hapū-led group in Northland surveyed eel numbers in local waterways and found longfins were almost entirely absent from rivers known to be commercially fished.

The Te Wai Māori Trust, which represents Māori interests in fisheries, has long lobbied for protection of tuna. As with most fisheries brought into the Quota Management System (QMS) since the mid 1990s, iwi were granted 20 per cent of the longfin eel quota.

Several iwi have refused to use their quota, however, due to concerns about the sustainability of the species.

'We cannot continue on as we are, we need immediate action to halt the degradation of tuna habitat,' Te Wai Māori Trust chairman Ken Mair said earlier this year.

'It is imperative that we act now to preserve this taonga species for generations to come.'

The focus on commercial eeling has long been seen as unfair by eelers themselves.

The species face many threats, and chief among them is habitat loss. Dams have blocked off around one third of the species' usual habitat, and the likes of pumps, weirs, and culverts have made life much more difficult for all native fish.

While our rivers have been transformed, the eel industry has changed, too.

Commercial eeling has been undertaken for more than half a century, and at one point was one of the country's most lucrative fisheries.

At its peak, in the early 1970s, more than 2000 tonnes of eel were exported each year, largely to the United Kingdom so it could be canned as jellied eels, a once-popular treat. At the time, there were at least two dozen eel processing facilities around New Zealand, and the fishery was essentially unregulated.

The industry's transformation since then has been significant.

In recent years, total eel exports have fallen to around 500t. There are now a handful of eel processors, all of which are small.

While the decline has been gradual, it kicked into higher gear a few years ago.

Less than a decade ago, the annual export value of eels reached a recent high point of $7m. Since then, it has more than halved – for three years in a row, it has fallen below $3m.

The export data combines longfin and shortfin eels, but it's easy enough to estimate the export value of just longfins.

Nearly all eels caught in New Zealand - around 98 per cent - are exported. Historically, around 25 per cent of eels caught are longfins. This would indicate the export value of longfin eels is around $700,000 a year, or 0.000009 per cent of national exports.

This means it's a small industry, even among fisheries. The longfin fishery is ranked 42nd in economic value - a metric which considers export receipts and the value of quotas - which makes it 200 times less valuable than the most important fishery, rock lobster.

One problem is that shutting down the longfin fishery would likely close the more valuable shortfin fishery, too - the ability to take either species is part of what makes eeling economically viable.

It is why eelers have strongly resisted attempts to shut down the longfin fishery. Some in the industry believe they've been made a scapegoat for wider issues.

'There's quite an in-depth management regime behind the eel fishery, and there always has been, but people just haven't bothered to recognise it,' says Vic Thompson, who has a stake in several eel processors, including Mossburn Enterprises, the largest in the South Island.

The eel fishery is not unregulated – far from it.

There are minimum and maximum size limits, and strict reporting requirements. Eelers are not allowed to fish in national parks, and some areas have been set aside as customary fisheries for Māori.

Thompson, as well as the Ministry for Primary Industries (MPI), points to data which shows around 70 per cent of longfin eel habitat is not fished. Thompson says many in the industry voluntarily opt not to catch migrating eels above 2kg, so they can escape to sea.

Since the longfin eel was included in the Quota Management System, the total allowable catch for the species has rarely, if ever, been met. In the last couple of years, the reported longfin catch has been around half of what eelers were allowed to take.

Despite these facts, calls to protect the species have focussed on the declining industry, in part because it's an easy target.

'When you start looking at the nuts and bolts of it all, everyone in New Zealand is contributing to the loss of habitat for eels,' Thompson says.

'We all need the hydro-electricity to make the country go, but it's not clean and green, because it's killing eels.

'If we [eelers] are not there, it's still going to carry on.'

Eel processor Vic Thompson, pictured in 2012.

UNSETTLED SCIENCE

It points to what is likely the most difficult aspect of the debate: There are various threats to the species, all of which are managed by separate agencies, which each have some responsibility for their protection.

The commercial fishery has received attention because it is - in theory - the easiest problem to solve.

If fishing is deemed to be contributing to a decline in the population, the Minister of Fisheries has the power to shut it down unilaterally by setting a catch limit of zero.

It is much harder to rip hydro dams out of rivers, particularly given they provide the vast majority of the country's electricity.

This was the reasoning behind the Parliamentary Commissioner for the Environment's (PCE) 2013 call for a moratorium on commercial fishing of longfins: It was 'the only way to make a difference reasonably quickly', she wrote.

This never happened, and the reasons why have been - and remain - contentious.

At its core is the information used by Fisheries NZ (part of MPI) to make judgments about the sustainability of the longfin population.

Fisheries NZ says it is confident in the data it uses, and says it follows international best practice. The PCE, however, has called it 'inadequate', a view shared by some freshwater ecologists.

Understanding why this data is contested requires knowing where it comes from.

There are two primary sources: Catch per Unit of Effort (CPUE) data, which comes from reports by commercial fishermen, and elver population data, which come from seven dam sites across the country.

The CPUE measures how many eels (in kilograms) a fisher can catch in a net in a given night. The logic is that if this number is steady or increasing, fishers are not struggling to find eels to catch, suggesting a stable population.

The use of this data has been controversial, not just for longfins, but for other fish species, too. That's because it is possible to maintain a stable CPUE while fish numbers continue to fall.

Critics say the efficiency of eeling throws a spanner in the works. If an eeler clears a river of longfins, they can simply move onto the next one, risking a phenomenon called 'serial depletion'. In this scenario, the CPUE would remain steady until it suddenly crashed when all the available sites had been fished, at which point it would be too late.

Eel industry figures have disputed whether this practice is commonplace.

'There are too many big eels in new areas that would need to be graded out,' Vic Thompson says.

Freshwater ecologist Dr Mike Joy has long held concerns about longfin eels.

'The areas being fished have probably been fished for the last 20 or 30 years.'

The long lives of longfins, however, make this a particular risk. Even if an eeler rotates around sites in 10 year intervals, eels would have to dodge their nets many times throughout their lives, a nearly impossible feat given the efficiency of eeling.

The second dataset, elver numbers at dams, has come under similar criticism. The data comes from seven dams, spread across the country, in which elvers amass at the bottom, unable to move upriver.

This data record is not long. The first dam to count elvers was Karapiro, in 1996. Most of the others have data for not much longer than a decade, which is not long enough to establish long term trends, particularly for a species that lives for generations.

But the critical problem with this measure, freshwater ecologists have said, is that it doesn't account for what happens to the elvers once they're released.

Freshwater ecologist Dr Mike Joy is particularly scathing on this matter; he says he's seen what happens when elvers are moved at Patea dam in Taranaki, one of the seven sites where the data come from.

'They trap them at the bottom - and I've been there and watched this - they take tens of thousands of them, weigh them, put them in a ute and drive them to the top of the dam and tip them out.

'Then, the water just erupts with perch - they wait there at the same time every year to be fed. Every one of those elvers gets added to the list of elvers transferred over dams and most of them get eaten straight away.'

It also doesn't account for how the eels get back. In most cases, they can't. They need to be caught before they reach the dam and become mincemeat.

'Getting the little ones upstream is easy,' says Dr Don Jellyman, Niwa's eel expert.

'Getting the adults downstream … there's no silver bullet. It's a universal problem.'

Some of the hydro companies employ fishermen to catch eels before they hit the dam, so they can be moved manually downstream. This has several problems. Firstly, there's no precise way to tell when an eel will migrate, other than it usually happens at night during heavy rain.

Any eel that misses the net will die a painful death - the only way past a dam is through the turbine.

Eel expert and NIWA Emeritus scientist Dr Don Jellyman.

The power companies can open the dam's spillway, which would allow the eels to pass through it like a waterslide, but they've been reluctant to do so with any regularity, Jellyman says.

'Hydro companies don't want to hear that, really. It's all lost generation as far as they're concerned.'

In a best case scenario, there would be data around how many eels actually live in rivers, along with their size distribution. This would show whether there were enough young eels to sustain a healthy population.

This data is hard to come by, but it does exist. Such surveys were done by regional councils in Waikato and Otago, each of which surveyed more than 1000 longfin eels.

Both regions showed the number of elvers and the number of mature females were lower than they should be. In the Waikato, half of sites had no longfin elvers at all, and in Otago, no females larger than 4kg were found at all.

The PCE cited this data as a reason to be seriously concerned, and questioned why data like it wasn't being used by MPI. Niwa had a similar data set showing the size distribution of eels in rivers.

Another potential data source is the Freshwater Fish Database, which records observations of fish in rivers over time.

A study authored by Joy, released last year, used this data to map the declines of native fish, and found among the species with the steepest declines were longfin eels.

Fisheries NZ, however, still uses CPUE and elver counts as its primary data sources.

Whether this data is good enough to justify the continued fishing of an at-risk species is contentious, particularly when other data sources appear to show something else.

'They looking at just what's being taken in,' says Stella McQueen, an independent freshwater ecologist.

'They don't look at what's being released, or the full size distributions of what's there. The number of juvenile eels is getting smaller and smaller each time.'

When asked about the data it uses to assess the health of the longfin fishery, Fisheries NZ says it maintains confidence in its decisions.

'Fisheries NZ uses the best available scientific information,' a spokesperson says.

'It is considered international best practice and is independently peer-reviewed by a multi-stakeholder science working group.'

Any data used in the assessments needs to be approved by the Eel Working Group, which, as of 2018, has 21 members, comprising MPI staff, outside scientists, and other stakeholders.

The working group has previously rejected data offered to it, on the grounds it wasn't reliable enough. It included the age structure survey data collected by Niwa, and a population model that would estimate the pre-exploitation biomass of longfin eels.

Fisheries NZ says alongside the CPUE and elver data, it takes into account other research it commissioned (including the data around the amount of habitat fished), and consults with tangata whenua and other stakeholders.

The agency is confident longfin numbers are stable or increasing, and continually reviews and updates its science 'to ensure it is fit for purpose'.

'The available information indicates that the abundance of longfin eel stocks are stable and in many cases, increasing throughout New Zealand,' the spokesperson says.

'While [the agency] is committed to managing the impacts of fishing on eels this should not be looked at in isolation and we consider action needs to be taken to manage all factors impacting eel abundance to ensure their sustainability.'

A NEW GENERATION

The endless stream of reports, a 21-person strong working group, the massive stakes that come with ensuring the survival of a species found nowhere else in the world, all for a small industry with annual exports of $700,000. How has it managed to survive?

Mike Joy says the commercial plunder of an endemic species has been enabled by authorities too afraid to shut it down.

'It's a taonga, a valuable cultural thing to so many people, and this tiny proportion of people gets to destroy it,' he says.

'If it's you or me that gets made redundant, then it's tough s…, but if you threaten the job of a fisherman or a farmer than there's hell to pay.'

Amid the uncertainty about the fate of our eels, there is one promising sign.

In his semi-retirement, Don Jellyman is occasionally asked to talk about eels to schoolchildren. He recently spoke to students at a school in Christchurch, and helped them install a 'tuna townhouse' - a dark hiding place for eels - in a nearby stream.

When he was a kid, he killed eels for money; but it couldn't be any more different now.

'I say to them, these are like kiwi, they're a part of our culture. They get blown away with the life-story - these glass eels have already swum for thousands of kilometres, and now they're going to be in our rivers for 40, 50 or more years, and eventually they'll migrate all the way back,' Jellyman says.

'You ask if they've been to see the longfins at Willowbank [a Christchurch wildlife reserve] and they all put up their hands and go: 'Me! Me!'

'I think that's neat. Kids are starting to grow up with an appreciation for eels.'

For the young people of Ngāti Hikairo ki Tongariro, eels have not been a common part of their upbringing, like they were for previous generations of hapū.

That's starting to change. As part of their work, Lena and John Morgan educate the next generation about tuna, about why they must be valued and protected.

It's a lesson they wish everyone else would learn, too.

'You're not allowed to gather a kererū, or a kiwi, but a longfin eel that's indigenous to New Zealand, we're still allowed to commercially fish it? It's beyond us,' Lena Morgan says.

'For us, it's about restocking our rivers so we can eat from them again, and take our kids to those ancestral fishing grounds, teaching them sustainable fishing methods - that's what our hapū want to see.'