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lots of fish swiming superimposed on whitebait fritters
(Image composite: Getty/ Finnbar Lee. Design by Archi Banal)

ScienceSeptember 24, 2023

Your whitebait fritter still holds mysteries for scientists

lots of fish swiming superimposed on whitebait fritters
(Image composite: Getty/ Finnbar Lee. Design by Archi Banal)

It’s whitebait season, but there’s a lot more to these unique native fish than what you see on your plate. 

In spring, when the tide is high, a miracle happens. Underneath the water, clinging onto grasses and rushes, small beads burst open, and larvae wiggle out. As the tide drains, they are carried by the current, smaller than a fingernail clipping, out into the wide wide sea. 

This is how the life of īnanga, one of five whitebait species, begins. “They’re amazing fish,” says scientist Finnbar Lee, a researcher at the Cawthron Institute. “I think people would appreciate them more if they knew about their amazing life cycle of going to sea and returning to rivers.” 

a hand with a stribey little brown fish on in
A banded kōkopu: as they’re active at night, they are difficult to photograph, Lee says. (Image: Finnbar Lee)

There are lots of things people know about īnanga and their other relatives in the galaxiid family, a type of freshwater fish found throughout the Southern Hemisphere. We know they’re delicious, for one: during the whitebait season, which is happening right now, the translucent white larvae can be found (for a hefty price tag) sizzled with eggs (also expensive) and seasoned with lemon. They’ve been a source of food for humans for a long time. Māori have caught and eaten these fish for hundreds of years, using flax nets and drying them so they would last. 

After being washed out to sea – a way for the larvae to save energy, since swimming is tiring when you’re tiny – the migratory galaxiids … hang out and eat zooplankton? While it’s clear that they’ve grown a lot by the time they return to freshwater a month or two later, this part of their lifecycle is mysterious. This is partially because tiny almost-clear fish are hard to spot in the vastness of the ocean. “We have no idea what happens at sea,” Lee says. “We presume they’re eating zooplankton and phytoplankton – the sea is a resource-rich environment where there’s lots of food, so that is one reason to have the larvae there.” While migratory galaxiids don’t have natal homing, like salmon, meaning they don’t necessarily return to the rivers they came from, the mysteries about their marine life cycle mean it’s hard to tell where there are separate populations of the fish, and therefore they are harder to manage. 

two hands holding a fish with long strong fins for going up streams
The kōaro, or climbing galaxias, has strong fins for climbing up rocks and waterfalls (image: Finnbar Lee)

While predation is normal, there are also human-created threats to the pattern of life the migratory galaxiids have assumed over thousands of years. The unpredictable effects of climate change are an obvious one, Lee says. Will rising water temperatures, as we’ve seen in marine heatwaves around Aotearoa, make the fish’s metabolism faster, meaning they have to eat more or else return to the rivers skinny? How will sea level rise impact where eggs are laid? Will changing patterns of rainfall alter the kōkopu species, which lay their eggs in gravel and wait for a flood? “If you lay your eggs in the air and the flood doesn’t come, the egg runs out of food and dies,” says Lee, and I imagine thousands of hungry little beads, waiting for water that will never arrive. 

New Zealand whitebait numbers are now in decline and with several species being threatened, calls are increasing to revise and tighten whitebait fishing regulations around the country (Photo: Hagen Hopkins/Getty Images)

Introduced species are a threat, too. Laying eggs in gravel was historically a good strategy since it reduced the risk of predation, but there’s some evidence that rats and mice like to eat the eggs before they get a chance to hatch. Sleek brown introduced trout, joy of fly fishers, munch on the īnanga and kōkopu, too. Habitat damage doesn’t help: while councils are now mandated to make culverts and drains that fish can navigate, fish can accumulate in the ponds beneath pipes, trying in vain to get to the cool alpine headwaters they thrive in. “You see pools of fish, trying to get up, but they can’t,” Lee says. 

Community efforts have made a difference to the whitebait species, as well as the non-migratory galaxiids. “There are lots of people doing restoration at different levels,” Lee says. Riparian planting, which creates dappled shady habitats in the water and reduces the amount of sediment in the water, helps; so does providing hay bales for the fish to lay eggs on where there aren’t enough of the grasses they like. Lee says that improving rules around how much fertiliser and sediment gets into freshwater catchments will make a difference, since cloudy and algae-filled water is not a nice home for fish.

Native galaxiids will soon have a voice in parliament in Lan Pham, a freshwater ecologist with a high list ranking for the Greens, who loves these “critters” so much that she had several attend her wedding (in a tank). 

a man in a green shirt with a tree in the background
Scientist Finnbar Lee says there’s a lot more to learn about galaxiid species (Photo: supplied)

But at the moment, there is science to do too. “Whitebait are a fishery, but there’s a lack of data about the species,” Lee says. “They move between the rivers and the sea, which makes it hard to collect data: we don’t know what the populations are doing.” It seems like one whitebait species, the giant kōkopu, is naturally rare – but is it actually the case that its population has declined? Radically changed ecosystems make it hard to assess how many fish the rivers really can support. As an ecologist, Lee could make a guess, but with so much missing information “it could be orders of magnitude wrong.” Reducing how many juveniles are taken out by whitebaiting could improve the outlook for these species – but given how many other factors play a role, it also could not. 

The tides turning on migratory galaxiids mean that some people object strongly to eating whitebait, because these animals are not just at risk, but also integral participants in a whole ecosystem. Farming the fish is one alternative, with commercial operators entering the market.

Lee, at least, has caught the bug (just like galaxiids, who feed on invertebrates). “On holidays with my family, when we stay at an Airbnb by a stream, I always bring my headtorch and a few nets,” he says. At night, when the fish are active, he goes to look for them, to catch them and have a look. There they are: silvery īnanga bellies, banded kōkopu’s electric stripes, speckled giant kōkopu blending in to the stream bed. Then he lets them go.

“I think they’re fabulous, they’re stunning fish,” Lee says. “Kōaro, the climbing galaxias, can climb up vertical surfaces with their pectoral fins, they go up waterfalls to get to mountain streams, they’re amazing.” With so many threats, and not enough data, protecting the species is vital. “It would be a disaster, an absolute disaster, if we lost them.”

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a shiny river with a "policy n 2 minutes sticker on the image a braided south island kinda wide blue river
(Image: Southern Lightscapes Australia via Getty, with additional treatment by Shanti Mathias)

PoliticsSeptember 21, 2023

Election 2023: The climate change and environment policies in two minutes

a shiny river with a "policy n 2 minutes sticker on the image a braided south island kinda wide blue river
(Image: Southern Lightscapes Australia via Getty, with additional treatment by Shanti Mathias)

What does each party say they’ll do for the environment? Policy.nz has the thorough version and we have the two-minute version. 

This is the first in our 2023 series of policy in two minutes explainers.

The last term of government has seen some severe natural disasters, including Cyclone Gabrielle, the Ashburton floods and the Lake Ohau fire. At the same time there has been awareness of biodiversity loss in the Hauraki Gulf, marine heatwaves, freshwater contamination, high net emissions and a range of other threats to the natural world and the people who live in it – that is, all of us. With the climate crisis continuing to exacerbate these disasters, what are different political parties saying they will do to respond to it if they’re in government? 

Emissions reduction and climate adaptation

Not every party is on the same page about how to reduce emissions. Act suggests that having parliament sit less would reduce emissions from flights; they want to end subsidies, repeal the Zero Carbon Act and abolish the Climate Change Commission. Act and National would both use the Emissions Trading Scheme (ETS) revenue to create tax incentives for farmers, recognising more of the carbon sequestration that happens on farms and ending discounts for low-emissions cars

National would create new policy statements on renewable electricity and hydrogen to coordinate work on these energy sources through the country. They would work with businesses to reduce agricultural emissions and delay implementing agricultural emission pricing into the Emissions Trading Scheme until 2030

Labour also wants to fund climate-friendly businesses through its partnership with investment firm BlackRock, aim for 100% renewable energy and establish new research centres to study technology, climate change and pandemics. 

The Green Party wants to strengthen the ETS and Zero Carbon Act, create a Ministry of Green Works to stimulate the economy without an environmental burden and create legislation for the right to a healthy environment. They want to prioritise nature-based, rather than technology-based solutions to climate impacts and ensure climate resilience planning affirms tino rangatiratanga and supports Pacific countries

Te Pāti Māori wants to reduce emissions by banning synthetic fertilisers, seabed mining, oil and gas exploration and introducing further restrictions on mining on conservation land. They would include agricultural emissions in the ETS and create climate change resilience plans with whānau, hapū and iwi. 

The New Conservatives want to eliminate all climate-related taxes and support from the government. 

blue blobs and smoke stacks and dollar bills
Different parties have different ideas about how the Emissions Trading Scheme should work (Image: Tina Tiller)

Conservation and biodiversity

New Zealand First wants to change who is responsible for biodiversity by having local councils manage biodiversity priorities and rescinding the National Policy Statement on Indigenous Biodiversity. National’s policies for biodiversity are mostly centred on which activities can happen on conservation land, with the party focused on hunting rules, proposing a minister for hunting. They would limit the scope of “Significant Natural Areas”, a designation in resource consenting which affects how you can develop areas that have important natural biodiversity. Act would completely abolish these Significant Natural Areas and focus on conservation activities on private land, which the Labour Party would also like to encourage. Labour would continue funding for Jobs for Nature, a programme that has so far provided more than $1bn to support environmental work. 

Te Pāti Māori has said it will return conservation land to local iwi and hapū. The Green Party wants to increase pest and weed eradication and align work in New Zealand with global biodiversity practices. They’re also keen to support nature restoration in urban areas through working with councils too.

To look after biodiversity in Aotearoa’s huge expanse of ocean, the Green Party would create an oceans ministerial portfolio and an oceans commission to expand ocean protection while strengthening limits on fishing including bycatch, set nets and cameras on fishing vessels. All other parties have far fewer oceans and fishing policies, although Labour would increase protection for the Hauraki Gulf, and National’s policy to remove restrictions on recreational hunting extends to fishing too, as the party says everyone should be allowed to gather food for their families.  

Pollution and water

Freshwater pollution in New Zealand is a concern shared by most parties, while few have policies for other kinds of pollution. The Act Party wants to manage pollution with a market-based solution where landowners can trade nutrient discharges and water pollution within limits set by regional councils. The National Party would remove the reforms formerly known as Three Waters, relax drinking water rules and create a water infrastructure regulator

Te Pāti Māori would manage water pollution by recognising Māori rights to fresh water. The Green Party would set limits to nitrogen in waterways, a product of the dairy industry, and slowly reduce the use of synthetic fertilisers, while rehabilitating and protecting wetlands. Neither Labour nor New Zealand First has any publicised policy for freshwater.

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Madeleine Chapman
— Editor
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