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Kōura (freshwater crayfish) are a taonga species for Māori, a keystone species for ecosystem dynamics and an indicator species for ecosystem health. They are also a species that have been difficult to monitor using conventional scientific methods such as baited traps.

Te Arawa iwi have used a traditional trap known as tau kōura for hundreds of years. Tau kōura use whakaweku (bundles of bracken fern) that are lowered into waterways. They create hiding places for kōura. When the whakaweku is lifted, kōura living within the fern bundles are shaken onto a net.

In this activity, students learn about tau kōura history and design, and how to build whakaweku to monitor kōura.

By the end of this activity, students should be able to:

discuss what is meant by the terms taonga, keystone and indicator species when referring to kōura

discuss why the tau kōura design is fit for purpose

build a whakaweku from rarauhe/bracken fern fronds

use whakaweku to monitor kōura in a local waterway.

Download the Word file (see link below).

Nature of technology

Related content

Useful links

Acknowledgements

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Kōura (freshwater crayfish) are a taonga species for Māori, a keystone species for ecosystem dynamics and an indicator species for ecosystem health. They are also a species that have been difficult to monitor using conventional scientific methods such as baited traps.

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Kōura (freshwater crayfish, Paranephrops planifrons, P. zealandicus) are one of Aotearoa's original inhabitants. They have an ancient lineage that diverged from their Australian relatives about 60-109 million years ago. Because their entire life cycle requires freshwater, kōura are evidence that there has been continuous freshwater in Zealandia ever since our part of Gondwana broke up 60-80 million years ago. As far as our evolutionary history goes, kōura are as significant as tuatara, wētā and kiwi!

Kōura are a taonga species for Māori - they were once a staple food and a key trading commodity for iwi living in the Rotorua and Taupō regions. Ecologists regard kōura as an indicator species. Their presence signals a healthy ecosystem, while their absence is likely caused by poor water quality and/or disruptions caused by introduced plants and animals. While ecologists have a good understanding of stream-dwelling kōura, this hasn't always been the case for kōura that live in wetlands (repo) associated with rivers and lakes.

A new use for a traditional practice

Conventional monitoring of roto and repo-dwelling kōura has a few drawbacks. Baited traps tend to catch large aggressive males so this method doesn't accurately monitor smaller kōura or female kōura. Spotlighting, diving and underwater video monitoring also favour large males as they are easier to spot. These methods also require reasonable underwater visibility.

Fortunately, a conversation with kaumātua brought to light an old technique known as tau kōura - a way of collecting kōura that was still being used by two families from Ngāti Pikiao.

Nature of technology

The tau kōura method involves placing bundles of bracken fern on the lake bed, creating a habitat or refuge for kōura. In a modern tau kōura, the fern bundles (called whakaweku in Te Arawa Lakes rohe and koere and tāruke in other rohe) are tied along a line (tāuhu) and placed on the lake bed for about 6 weeks. Alternatively, individual whakaweku can be left in streambeds for 2 weeks. To count the kōura, the whakaweku are lifted onto a kōrapa (net) so they cannot escape. Kōura are shaken from the fern, data about their size, gender and reproductive state are recorded and the kōura are returned to the water.

Tau kōura represents over 500 years of mātauranga and rangahau (research). The technique is an effective yet inexpensive way for scientists, iwi and community groups to monitor kōura. The method has also been used successfully for monitoring freshwater crayfish in other countries! For example, freshwater ecologists in Staffordshire, England, are using whakaweku to collect endangered white-clawed crayfish for relocation to safer waterways. They've been able to safely collect crayfish of a wide size range and balanced sex ratios.

We retain the traditional names and history, and acknowledge the appropriate iwi and people, as we work to manage and sustain the kōura. We now have a scientifically robust method for sampling kōura that is being used in lakes and streams throughout New Zealand.
Dr Ian Kusabs (Te Arawa, Ngāti Tūwharetoa)

The value of kōrero in wetland restoration

For ecologists, iwi and community groups, the resurgence of tau kōura represents the importance of kōrero with kaumātua and whānau about their memories and current interactions with repo and wetland species.

If kōura were once mahinga kai, find out about the populations and/or harvesting practices. If there have been population declines, find out what may have caused the decline so that the causes can be addressed. Note that some whānau may not want to share the exact location of their harvesting areas, but they may be willing to answer questions about kōura populations and changes to habitat or land use.

The next step is to consider the ecology and environmental whakapapa of the repo system. Kōrero about the best areas to restore kōura. Habitat and water quality are key considerations. Preferred habitat includes undercut banks and lots of woody debris, good water quality and low levels of fine sediment. A monitoring and assessment survey will provide information about current conditions and can build a baseline to help monitor changes over time. Kōura are just one of many species that will benefit from repo restoration. Give some thought to how restoration might help native freshwater fish, aquatic insects and freshwater macroinvertebrates.

Nature of science

Activity idea

Useful links

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Kōura (freshwater crayfish, Paranephrops planifrons, P. zealandicus) are one of Aotearoa's original inhabitants. They have an ancient lineage that diverged from their Australian relatives about 60-109 million years ago. Because their entire life cycle requires freshwater, kōura are evidence that there has been continuous freshwater in Zealandia ever since our part of Gondwana broke up 60-80 million years ago.

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Short, useful overview.

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What does science tell us about New Zealand freshwater crayfish?

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From Science Learning Hub

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DOC

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Shell-like skin

Kōura has a hard shell-like skin so it is a crustacean, one of the large group of animals, the arthropods, so-called because their legs and bodies are protected by a jointed hard but flexible body covering.

This covering eventually gets too small for the growing animal. It then splits and is left behind, while the new skin underneath hardens. This is called moulting.

Species

There are two species of kōura found only in New Zealand. In the east and south of the South Island and on Stewart Island they are larger (about 80 mm long) and have very hairy pincers.

But kōura in the North Island and in Marlborough, Nelson and the West Coast of the South Island are slightly smaller (about 70 mm long) and have less hairy pincers.

It lives in fresh water such as streams, lakes and ponds, and even in swamps. Kōura shelter between stones on gravelly bottoms but they can burrow into muddy bottoms, and will burrow well down into swamps that dry out over summer, to wait until the water returns.

Survival

Kōura need oxygen like all living animals and plants which they get from the water through their gills, under the thorax where the legs join the body. Water is sucked in, pumped forwards over the gills and out through the mouth. If the gills get clogged they can back-pump to flush out any debris.

Kōura use their four pairs of walking legs to get around quite quickly - they do not crawl as their common name, 'crawly', suggests. They also have a sort of reverse gear, to shoot back into shelter when alarmed, by flicking their tail forwards violently. Their first pair of legs, their pincers, are used mainly for catching food, for fighting with invaders, or for waving menacingly at intruders. They can give a painful nip, so be careful.

Kōura is a scavenger that feeds on leftovers that float by in the water or settle on the bottom; old leaves, small insects are favourites. It does not go hunting for its food. Once food is caught in the pincers it is torn up, pushed into its mouth to be ground up and separated by a filter system that lets only fine pieces pass through to the small stomach to be digested.

Large trout love koura and so do shags.

Kōura/freshwater crayfish

Reproduction

Female kōura produce eggs between April and December, and most in May and June. She carries the berry-like eggs, between 20 to 200, under the side flaps of her abdomen, when she is said to be 'in berry'. Small kōura hatch about 3 to 4 months later, looking exactly like their parents in miniature. They cling to their mothers with their pincers until they are nearly 4 mm long, around December of their first year. By their fourth year they are 20 mm long and become adults.

Threats

Crayfish populations are decreasing in some areas as they are subject to habitat modification and land intensification.

Predation by introduced species has also played a role as has harvest for human consumption in some places. They are listed as a threatened species and their populations are in gradual decline.

You can help

Kōura/freshwater crayfish

Kōura have a special part to play in our freshwater lakes and streams. They are native animals and recycle some of the leftover materials by their scavenging, therefore helping to clean up our streams and lakes in their own small way.

As they are so slow growing and many do not reach adulthood, there are never too many. It pays to take care of them and put the ones we catch back where we found them.

Fence off your waterways or ponds from stock and plant native vegetation along the edge of waters.

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Kōura has a hard shell-like skin so it is a crustacean, one of the large group of animals, the arthropods, so-called because their legs and bodies are protected by a jointed hard but flexible body covering. This covering eventually gets too small for the growing animal.

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Article - discussion point; should taonga be farmed?

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The world wants our freshwater crayfish. Now there's a practical guide on how you can farm them and get a bite of the juicy price tag.
Words: Anna Tait-Jamieson

Not so long ago, when no-one doubted the drinkability of our rivers and streams, when no-one used words like 'swimmable' to measure water quality, one of the defining pastimes of a New Zealand childhood was searching for freshwater crayfish. Lifting up rocks and prodding the banks of streams to chase kōura (or crawlies) out of their hiding places was endlessly entertaining, and ultimately rewarding if you wanted a feed.

There were lots of kōura back then. They thrived in forest streams, in lakes and farm ponds, even in streams that flowed through city parks.

But not any more. Kōura are in decline. The blame lies squarely with our failure to care for their habitat. No-one knows more about this than John Hollows. He is a scientist and conservationist who has studied the impact of changing land use on our native crayfish. His conclusion?

"Kōura are on a hiding to nothing."

The solution: farm them.

John believes the global demand for freshwater crayfish can support a profitable niche industry and this will save the species. For the past few years, he's been developing a unique way of farming kōura in the forests of Southland and Otago. Everything he knows is in a recently-released, how-to guide that he hopes will encourage more people to do so. Freshwater Crayfish Farming: A Guide to Getting Started draws on his experience as aquaculture manager for the Keewai project. This is a business initiated by forestry company Ernslaw One to gain additional revenue from the hundreds of fire ponds in its forests. Normally, they are only used in the event of a fire.

But now, the ponds are steadily being stocked with kōura (brand named Keewai) for the high-end restaurant market. The business is commercially savvy, using existing infrastructure, but also award-winning. It won the Spirit of New Zealand Award in the Outstanding NZ Food Producer Awards 2017, for its sustainable approach and conservation ideals.

Some 500 ponds are now in varying degrees of readiness. Stocking a pond takes time, which means it will be years before the company can guarantee a steady supply, let alone make a profit. Last year John harvested just 250kg for sale. That's about half the estimated total national production from the country's four active farms. It's well short of the 10-tonne minimum needed to attract an overseas market.

John's booklet, backed by the Sustainable Farming Fund, is the first attempt to collate what is known about crayfish farming in New Zealand. It's aimed at everyone: large landowners, farm foresters, small farmers, and lifestyle block owners who want to stock a stream, irrigation canal or garden pond with a native species in need of protection. He's written it so people can avoid the years of trial and error experienced by the small group of pioneers who set up their own crayfish farms without guidance.

"We're starting an industry with a blank sheet," says John. "There is no blueprint so it's challenging. There's a lot of misinformation out there. This (book) is a document a lay-person can understand. In a couple of years, I'd like to think we can edit it."

The information draws on the methods used by farms in Marlborough, Kaikōura and Alexandra. These are all smaller in scale than Keewai, and semi-intensive in the use of supplementary feed and mechanical aeration of water in ponds and water races. But mostly, the guidelines are shaped by John's own experience, honed from years of research in the laboratory and many hours in a wetsuit observing kōura in their natural habitat.

The Keewai farming system is adapted to New Zealand conditions and is unique in its hands-off approach. Other countries have more intensive systems. In Australia, yabbies and the larger marrons are farmed in dams that are drained once a year. The French écrevisse are harvested from ponds in a similar way. In China and the Southern states of America, crayfish are farmed in rice paddies.
THE BASICS OF FARMING CRAYFISH
The Keewai system relies on modifying existing fire ponds, or digging new ones, to replicate the kōura's environment. Riparian edges are planted with native grasses and watercress, which provide both foliage and insects for the kōura to feed on.

New ponds are filled naturally with spring or rainwater and then left for two years. By the time the kōura are introduced, each pond has developed its own ecosystem, filled with everything crayfish like to eat.

Nothing is introduced. The kōura eat everything from plankton to plants, snails, and water boatmen, but they are not at the top of the food chain.

"Eels, trout, water rats, perch, even hedgehogs. Anything you can think of will have a crack at crayfish," says John. "They're such a lovely thing to eat."

To protect them, large branches of twiggy trees like coprosma are dropped into the middle of each pond. These act as natural refuges to save the kōura from harm, particularly when they moult. As a kōura grows, it sheds its outer skeleton, leaving a softer skeleton underneath that needs time to harden. During this time, they are more vulnerable to attack by predators.

The branches also give them a climbing platform from which they can gorge on the plankton that blooms on the surface water in summer.

3 REASONS IT'S A GREAT IDEA
* this is an easy form of land-based aquaculture, sustainable, and cheap to run, with returns of $100 per kilogram of crayfish.
* there are no feed costs
* labour is minimal for most of the year
5 DISADVANTAGES TO FARMING CRAYFISH
Labour becomes quite intensive during the short harvest season between February and April. At Keewai, forestry workers lend a hand to set baited nets. There's no way to drain the fire ponds so the harvest is completed with hand-held scoop nets.

The catch is sorted and the kōura are either thrown back, transported to new ponds for breeding, or taken to a purging facility before being shipped out live in chilled boxes.

The system is low yield because:
* it takes a great many ponds to grow a sizeable population;
* left to their own resources and with no extra feed, only five percent of eggs make it to their second year;
* in these conditions it takes three years to raise a juvenile South Island kōura to a saleable weight of 70g-100g - the North Island species, which also occurs in the north and west of the South Island, is generally smaller and sold at around 50g;
* more intensive systems raise denser populations with faster growth and better yields, but at a higher cost.
THE KEY INGREDIENT: WATER
Water is the main consideration. Habitats can be created or modified from new or existing ponds, dams, streams or canals but they need to be clear of sediment. The water source - spring, stream or rain - must be clean. Kōura is extremely sensitive to water quality and will only live in pristine conditions.

"Herbicides and pesticides will kill within hours," says John. "Keep spraying well away from the water and riparian areas."

Then there are pests and diseases. New Zealand has a market advantage as it is free from the crayfish plague which has devastated stocks in other countries.

There are one or two other lesser diseases to look out for, chiefly the whitetail fungus. To limit predation by eels and perch, stream-fed ponds should be fenced or fitted with traps. Prospective farmers will also need to source seed stock, dig ponds, set up purging facilities, and maybe hatcheries.

All these activities require consents and permits from government agencies, territorial authorities or other groups. John warns it pays to do the homework before embarking on a commercial venture.
THE FUTURE OF CRAYFISH FARMING
Several parties are already on track. John is working with iwi in Hawke's Bay and Southland, but he also has small landowners in his sights. He says the beauty of kōura farming is that it doesn't affect the water source. It can co-exist with other farming activities, adding an additional income stream for vineyards and lifestyle blocks. Where income is not an incentive, he offers breeding stock for stream restoration projects.

He's also advocating the formation of an industry association to share knowledge and experience, and to promote ongoing research in the following areas:
* selective breeding for faster growth;
* artificial rearing of eggs for higher survival percentage;
* research into the benefits of feeding, eg conversion rates, cost-benefit, and taste profile.

John believes the best way to ensure the survival of a species is to farm it. He says anyone with a garden stream or pond could raise kōura for fun. Children love searching the banks for the nippy little beasts and it's a great way for them to learn about conservation and their natural environment.
GET THE GUIDE
You can read and download Freshwater Crayfish Farming - A Guide to Getting Started here.

5 things you might not know about kōura

* Kōura are a traditional food for Maori, who have several ways of catching them in the wild. One method is to tie up a large bundle of bracken and leave it on a pond bed attached to a rope. The crayfish climb between the branches and use it as a refuge, effectively trapping themselves. This method of harvesting is still used in the Rotorua Lakes area.
* Both North and South Island kōura are in decline, with the South Island species formally listed as threatened. Despite this, neither species is protected and people can take up to 50 per person per day. However, there are areas where iwi control fishing so it pays to ask. Crayfish from Taupo and the Rotorua Lakes can only be taken by Maori.
* Kōura are night feeders. Try catching them by baiting a stocking with a piece of meat. Lower it into the water and wait. Their claws get caught in the stocking which makes them easy to haul out.
* After years of working with kōura, John likes them too much to eat them himself. But if you do, he says purge them for a couple of days in several changes of fresh water (not tap water) before cooking. Chill them in the freezer for an hour or two until they stop moving, then drop them into boiling water and cook for about 1 minute until they turn red. Alternatively, chill, then spike them in the head and halve them lengthwise. Barbecue while basting with oil or melted butter. Finish with a little salt and a squeeze of lemon or drops of balsamic vinegar.
* The tail has the most meat, followed by the claws. The rest can be used to make a flavoursome stock or bisque.
THE KōURA FARMS OF NZ
www.sweetkoura.co.nz - Alexandra
www.clearwatercrayfish.co.nz - Wairau Valley, Marlborough
www.waikourasprings.info - Kaikōura
www.keewai.co.nz - Otago and Southland
READ MORE:
Sustainable crayfish venture wins accolades

Recipe: Koura in a spicy coconut sauce

This article first appeared in NZ Lifestyle Block Magazine.

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How to farm New Zealand freshwater crayfish Koura - thisNZlife

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The world wants our freshwater crayfish. Now there's a practical guide on how you can farm them and get a bite of the juicy price tag. Words: Anna Tait-Jamieson Not so long ago, when no-one doubted the drinkability of our rivers and streams, when no-one used words like 'swimmable' to measure water quality, one of ...

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Excellent overview

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Importance, tau, restoration

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Tau kōura sample collection and processing protocol

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Tau kōura sample collection and processing protocol

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It is commonly used to harvest kōura or freshwater crayfish ( Paranephrops planifrons) in the Te Arawa and Taupō lakes, where kōura are abundant.

A variation of tau kōura which makes use of individual fern bundles is also used to harvest kōura and small fish (e.g. elvers and whitebait) in streams, rivers and the shallow shoreline areas of lakes, ponds and wetlands. These fern bundles bundles are known as whakaweku in the Te Arawa and Taupō districts, and as koere and taruke in other areas.

Individual whakaweku can be used as a kōura monitoring tool and, like the tau kōura method, have significant advantages over other monitoring tools in many situations.

They are particularly suitable for use in non-wadeable streams and rivers, and by iwi and community groups who do not have access to specialised electric fishing equipment. Whakaweku catch good numbers of kōura, without the sex and size biases of other sampling methods such as baited traps and nets. Sampling kōura using whakaweku is also inexpensive. (See related publication on tau kōura as a sampling method).

Whakaweku construction

1. Collect bracken fern (Pteridium esculentum) fronds by cutting them off near ground level. This leaves the rhizome intact so that the fern regrows quickly.

2. Construct bundles of about 10-12 fronds by binding their stems together. Using strong plastic cable ties, adjust the fronds so that they form an open bunch, and cut the ends off the fern bundles to make a "handle" (Fig. 1)

Tau kōura sampling equipment (no boat):

A kōrapa (a portable kōura landing net)

Waders

An ice cream container or two for sorting and holding kōura

Calipers for measuring kōura size i.e., orbit carapace length (OCL).

Clipboards, pencils and water-proof paper for data recording

A bucket for holding sampling equipment and/or kōura.

If you are sampling koura in a lake or large river using a boat, include the following:

You will need a kōrapa to collect the koura, to avoid kōura escaping in response to air exposure. To make a kōrapa (1.2m wide x 2m high) you will need the following materials:

aluminium frame (a local sheet metal engineering shop should be able to construct this)

shade cloth (70%)

cable ties to attach shade cloth to frame.

Video 1 - retrieving the whakaweku in Te Wairoa Stream [Video credit: M. Katipa]

See publication detailing the use of the tau koura in Lake Rotoiti. [PDF 200KB]

Kōrapa

Where to put your whakaweku

You can set whakaweku anywhere in a stream where the water depth is greater than about 50 cm, including in deep pools, beneath undercut banks or mid-stream. The whakaweku work even if they are not fully submerged in water.

Retrieving your whakaweku sample

Leave the whakaweku to be colonised by kōura for about two weeks before sampling. Then:

retrieve it by positioning your kōrapa immediately downstream of the whakaweku

drag the whakaweku into it (Fig. 4)

lift the kōrapa out of the water and place it on the bank before shaking the kōura out of the whakaweku and into the kōrapa (video 2)

place the catch from the whakaweku into an ice cream container and process

note the presence of bycatch such as fish and other macroinvertebrates.

Acknowledgements

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Tau kōura sample collection and processing protocol

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It is commonly used to harvest kōura or freshwater crayfish ( Paranephrops planifrons) in the Te Arawa and Taupō lakes, where kōura are abundant. A variation of tau kōura which makes use of individual fern bundles is also used to harvest kōura and small fish (e.g.

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(noun) North Island freshwater crayfish, Paranephrops planifrons, South Island freshwater crayfish, Paranephrops zealandicus - found in native forest, exotic forest, and pastoral waterways, but very rarely in urban streams because of chemical pollution, increased flood flows from stormwater inputs, and degradation of habitat.

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(noun) string (of a garment, etc.), loop or thong (of a patu).

(noun) tie, fastening, string, cord (of a bag, etc.).

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Bundle of bracken fronds.

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(noun) post, pole, stake.

(noun) stake for marking boundaries of fishing grounds.

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(verb) (-tia) to anchor, fix with an anchor.
(noun) anchor, lump, swelling.

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(noun) ridge pole (of a house), ridge-beam (of a house), main theme, subject of a sentence.

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New Zealand Native Fish on Facebook Watch

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A traditional Maori method of catching koura (freshwater crayfish) using a 'tau koura', or fern bundle, has worked well in koura abundance monitoring trials.

The tau koura is a traditional method used by Te Arawa and Ngati Tuwharetoa to catch koura in Central North Island lakes. The technique involves placing bundles of bracken fern ( Pteridium esculentum) on the lakebed that koura then colonise.

New research carried out by independent consultants and NIWA at Lake Rotoiti shows that tau koura had significant advantages over conventional monitoring methods such as baited traps and dive surveys.

Problems with conventional koura sampling and monitoring methods

Conventional sampling methods - baited traps, scuba diving, and underwater video camera -were all found to have a number of disadvantages in a preliminary study of koura sampling methods in the Rotorua lakes.

Trapping

mainly attracted large koura

koura attracted to the traps only if natural food supplies limited.

Diving and underwater video cameras

also biased towards large koura

heavily dependent on water visibility.

Advantages of tau koura

Tau koura:

captured a large number of koura of a wide range of sizes, in both shallow and deep waters

male and female crayfish of all sizes colonised the fern bundles

can be used in murky waters and at any depth

does not require specialised knowledge or expensive equipment.

So tau koura appears to provide more representative data on population structures than alternatives. Tau koura could be especially useful for monitoring by iwi and community groups, and in difficult conditions.

Environments where any koura monitoring is difficult

The tau koura method cannot be effectively used in high-growing aquatic plant beds, or areas of large boulders or wood. The fern bundles become entangled and difficult to retrieve.

But using baited traps, diving, and underwater video camera surveys are all difficult in these types of environments.

Retrieving used tau koura (Chris Hickey)

Monitoring by local iwi and community groups

Te Arawa Lakes Trust consultant Ian Kusabs, who has worked with NIWA on this project, says there are large numbers of koura living in North Island lakes.

"Koura are an important traditional food source for Maori. Maori are reasserting their kaitiakitanga (sustainable protection of resources), and it is important that iwi can monitor the wellbeing of species such as koura.

"There is a lack of quantitative information on koura, which makes it hard for iwi and government agencies to manage the koura populations in the lakes. The main reason for this lack of information is the lack of suitable methods to sample populations. That is why we need a more appropriate method.

"The tau koura method is particularly suited for use by iwi, who have exclusive rights to harvest koura in the Rotorua and Taupo lakes, and community groups. It is inexpensive, does not require specialist expertise, and avoids safety issues associated with diving."

Further work is planned to investigate how quickly koura colonise the fern bundles and the effects of lake water quality and different sorts of lakebeds and plants on koura populations.

Contact: Ian Kusabs ( ian@kusabs.co.nz)
Full paper - New Zealand Journal of Freshwater and Marine Research 43 (3)

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Traditional Māori fern bundles a better way to catch koura

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A traditional Maori method of catching koura (freshwater crayfish) using a 'tau koura', or fern bundle, has worked well in koura abundance monitoring trials. The tau koura is a traditional method used by Te Arawa and Ngati Tuwharetoa to catch koura in Central North Island lakes.

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Some good info on biology, diet etc.

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One of New Zealand's largest forestry companies has lifted the concept of sustainable harvests and diversification to new levels by stocking its fire-fighting ponds with freshwater crayfish, a species on the Department of Conservation's threatened species list.

Ernslaw One is the fourth-largest forest owner in New Zealand, a Malaysian and Chinese-owned specialist softwood producer with extensive forests in the Coromandel, Gisborne, Ruapehu, Manawatu-Rangitikei regions and 10 forests in Otago and Southland.

After a slump in world log prices several years ago, the company investigated alternative revenue streams, including farming freshwater crayfish.

Aquaculture manager John Hollows says a lot of people probably don't even know the crayfish - or koura - exist. Their distribution is shrinking through loss of habitat and they are listed by the Department of Conservation as a threatened species.

"It's a really unique opportunity to farm a native species and sell them," he says. "I can't think of any other species worldwide in that same position."

Ernslaw's stocks of crayfish could help in habitat restoration work in future or in conservation of wild stocks if the species was ever threatened with extinction.

The commercial market for freshwater crayfish is still in its infancy in New Zealand with only 300kg of fish sold annually.

Seventeen permits to farm them commercially have been allowed and most operators are still in the early stages of development. Only four farmers have stock for sale, all in the South Island.

Most operators have adopted the Australian model where crayfish are intensively managed and fed to grow fish to a saleable size in one year, a system that carries associated costs.

"Our product has a really good story behind it," Hollows says.

Ernslaw One was initially granted permits by the Ministry for Primary Industries to collect wild stocks from local rivers and streams but actually sourced most of its stock from its own forests.

The company has stocked 400 ponds spread through 11 of its forests in the Otago and Southland region. Ponds are dug and left for a few years to stabilise before seed stock of the local species is introduced.

"At the moment our focus is on building ponds and stocking them. One of the things we identified early on was not to put all our eggs in one basket. They are spread far and wide at the moment and we haven't had any problems."

"We'll probably stock well over 100 new ponds this summer but it will probably be two or three years before we see a return for that."

Ernslaw One uses natural materials from the forest like broom and bracken to create habitat for crayfish to settle in and has established native aquatic plants like watercress for cover and as a food source as the population increases.

Otherwise, the fish are left to fend for themselves with no artificial feed supplements provided.

Crayfish are an aggressive predator. "There is nothing they won't eat," he says. "I've seen a trout swim past with a crayfish latched on to its fin."

While they are a tough, long-lived species they are sensitive to pollutants, herbicides and insecticides. Ernslaw's ponds are spring or rain-fed ponds so are not affected by any pollutants carried in waterways and therefore act as a barometer of environmental health of the company's forest.

Last year it harvested its first crayfish at three to four years of age, a saleable weight of 50 grams and received great feedback from restaurant chefs and food critics.

Hollows says in Australia "yabbies" are harvested annually and "with apologies to our Aussie cousins, taste like mud. Our's have a sweet flavour and I think that reflects the environment they grow in."

Ernslaw One's project has had a positive response from many organisations, including Ngai Tahu, Fish and Game and the Ministry for Primary Industries. The latter has contributed funding through the Sustainable Farming Fund for more research into replicating natural habitat.

One of the outcomes of that research will be an updated guide on how to farm freshwater crayfish in New Zealand so interested parties can make informed choices without having to reinvent the wheel.

"People have been really helpful," Hollows says. "They really like the idea and want to see us succeed so they help us get permits and get paperwork through."

Selling the Kiwi-grown delicacy, which fetches prices of $80-$90 a kilogram in New Zealand, was a marketer's dream, he said.

"We're fielding inquiries every week and it's just a shame we can't fill these orders. There would be no problem filling demand for 10 tonnes of crayfish if we had it."

"We're still building up biomass so we can supply markets consistently. That has been the thing that has probably held the industry back a bit. No-one has been able to supply markets consistently and restaurants need a stable supply."

He believes producers need to focus on supplying New Zealand markets first before even thinking about exporting.

With only 19ha of farmed freshwater crayfish in permitted ponds in New Zealand at present, the potential for development is huge, particularly with the expansion plans of irrigation schemes, storage ponds and canals in the South Island.

"We realised we're never going to saturate the market so there may be some benefits in more large-scale farmers in the industry looking at a collective to supply export markets."

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One of New Zealand's largest forestry companies has lifted the concept of sustainable harvests and diversification to new levels by stocking its fire-fighting ponds with freshwater crayfish, a species on the Department of Conservation's threatened species list.

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Species colouring sheets!

There are simple and slightly more complex versions of each species - each has an image to colour and some fun facts. We've called them 'junior' and 'senior', but whatever works for you! Pictures shown are for the senior versions.

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Freshwater Colouring-in | Classroom Resources | Taupo for Tomorrow

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Species colouring sheets! There are simple and slightly more complex versions of each species - each has an image to colour and some fun facts. We've called them 'junior' and 'senior', but whatever works for you! Pictures shown are for the senior versions.

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A constant flow of dying crayfish seen floating down a freshwater spring stream has caused alarm and seen officials rushing to find the cause.

Keen trout fisherman Erin Hampson-Tindale was shocked to discover what he described as "thousands" of the freshwater crayfish (koura) of all sizes and ages floating past him during a visit to Oraka Stream in Putaruru, South Waikato, on Tuesday.

During the hour he spent there he saw a constant flow.

"It's shocking, there are literally thousands and thousands stumbling past," he said.

READ MORE: Droves of dying koura float down stream

Hampson-Tindale said it looked like a whole colony had been wiped out by something because there are even really tiny ones.

But just what the cause was remains a mystery.

Waikato Regional Council senior communications advisor Stephen Ward said council staff were immediately sent to the stream on hearing the news.

"By the time council staff arrived on the scene they could see a smaller number of koura in the water than originally reported," he said.

"They took water samples, with results expected within the next week.

"They also searched the immediate area to see if they could find any obvious sign of what might be affecting the koura but found nothing."

Ward said the staff would be conducting a wider inspection of the area for potential sources of contamination.

The council's incident response team leader Derek Hartley said the council was determined to find the source of the issue.

"We're really keen to understand what's caused this problem for the koura," he said.

"We haven't seen any other signs of aquatic life being affected at this stage."

Hartley said anyone who sees more dead koura or other aquatic life in the area should contact the incident response team on 0800 800 401.

"Also, we're keen to hear from anyone who has any information about what might have caused the problems with the koura," he said.

Hampson-Tindale said he also saw a few dead trout but there were no obvious signs of contamination in the river that he could see that might have caused the deaths.

"The water is not as clear as it can be but it could just be from the rain we had [on Monday], other than that it really looks fine," he said.

"It's hard to say what has caused this but I know koura are sensitive when it comes to contamination."

Hampson-Tindale said it was a depressing situation to come across.

"Not many streams would have this amount of koura. They are also the main food sources for trout and they are going to gorge on them," he said.

"This is not something we can wake up tomorrow and forget about, it needs to be monitored."

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A constant flow of dying crayfish seen floating down a freshwater spring stream has caused alarm and seen officials rushing to find the cause. Keen trout fisherman Erin Hampson-Tindale was shocked to discover what he described as "thousands" of the freshwater crayfish (koura) of all sizes and ages floating past him during a visit to Oraka Stream in Putaruru, South Waikato, on Tuesday.

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Waikato Regional Council staff are confident the stream in Putaruru where dead koura were found late last year is now supporting a healthy ecosystem.

However, they are yet to determine the cause of death for the freshwater crayfish.

On Friday, council staff were on site at the Oraka stream. They reported spotting healthy koura and other aquatic life, including eel and trout.

Investigation and incident response manager Patrick Lynch said it is fantastic to see the stream that appears to have completely recovered from whatever occurred in December.

READ MORE:
* Droves of dying koura float down stream
* Freshwater stream's dying crayfish

But he said staff were determined to find out exactly what happened and ensure it does not happen again.

"We'll now be conducting tests on the bodies of koura collected from the stream to try to establish whether their death is linked to water quality, or some other cause."

On December 20, 2016, "thousands" of dead koura were seen floating downstream in what appears to have been an isolated, short-term event.

Council said they carried out extensive searches and took a large volume of water samples on the day and the following days. The final analysis of the water samples was completed this week.

But Lynch said the final results of those tests won't be through for some weeks.

"The council has taken this incident very seriously with staff on site over five consecutive days late last year, and a science and incident response team there today.

"We'd welcome any more information from the public over this incident."

The council's investigations team is available on 0800 800 401.

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Waikato stream 'healthy', but investigation continues into koura deaths

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Waikato Regional Council staff are confident the stream in Putaruru where dead koura were found late last year is now supporting a healthy ecosystem. However, they are yet to determine the cause of death for the freshwater crayfish. On Friday, council staff were on site at the Oraka stream.

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An aerial insecticide spray operation is thought to be the cause of large numbers of freshwater crayfish (koura) dying in the Oraka Stream near Putaruru in December 2017.

However after a year-long investigation, the Waikato Regional Council will not be prosecuting or sanctioning the companies involved due to a lack of evidence.

"Though not to an evidential standard we believe that we identified the cause of the crayfish deaths, being the aerial spray operation and that, in all probability, cypermethrin is the primary killer of these creatures," the council's investigations and incident response manager Patrick Lynch said in his report.

Cypermethrin is the main ingredient in Alpha Scud, an insecticide used during the spraying.

READ MORE:
* Residents reassured after popular South Waikato stream poisoned twice in one year
* Freshwater stream's dying crayfish
* Waikato stream 'healthy', but investigation continues into koura deaths
* Risk of crayfish plague stifles search for water contaminants

Lynch said they had not been able to conclusively establish the spray was the cause of death despite cypermethrin being "an ideal killer" of freshwater crayfish.

"Therefore it only remains a possibility, albeit probable, that the aerial spray was responsible."

Lynch's report was presented to the council's Environmental and Services Performance Committee at its February meeting.

The spraying had taken place at Pinedale Forest on December 16, the same day that the council were alerted by a member of the public about the crayfish deaths.

It was being carried out by a helicopter company for a forestry company, which owned and managed the trees on a pine forestry block. The land where the trees were growing was owned by another entity.

The spraying was to prevent the spread of the paropsis beetle, which affects the gum trees surrounding the forest.

Enquiries made by council staff showed they could not establish any wrongdoing by the helicopter company. Water samples were also collected from the Oraka Stream failed to show anything of concern.

Waikato University's School of Science tested flesh samples of the dead crayfish for cypermethrin.

The associate professor responsible for the testing informed council staff that while the results showed cypermethrin was below trace levels. "He said that is not to say cypermethrin is not present in samples. It just could not be detected," Lynch wrote.

"It is his opinion that it is almost the ideal chemical weapon to use against the likes of freshwater crayfish."

The insecticide, combined with the chemical makeup of the stream could also form another compound that was potentially more deadly than the Cypermethrin, the associate professor said.

He went on to say that the Oraka Stream's flow and water volume meant it was highly unlikely a meaningful testing sample could be taken.

The council met with the forestry company and the landowner in December where it was decided no more spraying would be carried out until other beetle control options were looked at.

"On a positive note, there has not been a reported further incident. This may well be as a result of staff engaging with the forestry company and landowner," Lynch said.

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Aerial insecticide spraying the most likely cause of freshwater crayfish deaths

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An aerial insecticide spray operation is thought to be the cause of large numbers of freshwater crayfish (koura) dying in the Oraka Stream near Putaruru in December 2017. However after a year-long investigation, the Waikato Regional Council will not be prosecuting or sanctioning the companies involved due to a lack of evidence.

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Taonga & mahinga kai species in Te Arawa lakes - kōura

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Taonga & mahinga kai species in Te Arawa lakes - kōura

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Studies of native and introduced freshwater fish have shown that fish are highly resistant to 1080, even when exposed in field trials to very high concentrations of 1080 in water and food. Read the facts here.

Do 1080 baits in water harm fish?

No. Studies on multiple fish and aquatic species show that fish in water where 1080 is present are not affected.

NIWA monitored 16 sites across 4 streams before and after 1080 baits were added to the water at 10x the possible quantity that might fall into a stream during a 1080 drop. Three species of native fish, longfin eels, koaro, and upland bullies were monitored following the addition of 1080 to the water. The evidence: No fish died or suffered adverse effects. [1]

In a Landcare study, no 1080 residue was detected in the flesh of longfin eels exposed to 1080 cereal baits, and 1080 dissolved in water.[2]

A NIWA study of the effects of exposing koura (native crayfish) to 1080 baits showed that koura did not absorb 1080 from the water.[3]

In another study fingerling trout subjected to water with 1080 concentrations of 500 and 1000mg per litre showed no visible effect.[4]

In a US study fingerling bream and bass survived indefinitely in water containing 370mg of 1080 per litre, with no sign of any toxicity.[5]

What happens when fish eat 1080 bait?

Some fish do not eat 1080 baits whereas others do. In several studies fish have been force-fed 1080 to study its effects. In those studies no fish died or showed visible adverse effects, although some temporarily absorbed 1080 in very low concentrations.

In the Landcare study, The evidence: no 1080 bait was eaten by any of the longfin eels exposed to 1080 baits in water.[6]

In the NIWA study on koura, it showed that they did eat some 1080 bait. If they ate bait soon after it was dropped into the water, there would be traces of 1080 in their gut and tail muscles, though this had no visible adverse effects on them.[7]

Fingerling and adult trout force-fed with cereal pellets containing 4 to 8mg of 1080 also showed no visible effect.[8]

In a study for DOC, which analysed the uptake and elimination of 1080 in trout that were force-fed high doses of 1080 gel, no trout died or showed ill effects, although trout flesh had taken up low levels of 1080 . DOC referred the results to the Ministry for Primary Industries (MPI) to assess food safety.[9]

What happens if fish eat an animal that has eaten 1080 bait?

In the Landcare study, longfin eels were also fed possum meat that contained 1080 residue. None died or suffered adverse effects, although low concentrations of 1080 were found in the flesh of some eels shortly after they had eaten the poisoned possum gut meat.[10]

Is there a risk to humans from eating fish with 1080 residues?

If you catch and eat fish from areas where there has been a 1080 operation, the risk of 1080 poisoning is extremely low.

The evidence: MPI found that the peak 1080 levels temporarily reached within the force-fed trout, fall well short of breaching internationally accepted standards for human health.[11]

The concentrations of 1080 found in eels are so low that to risk death a 60kg person would need to catch and eat 5.5 tonnes of eel that had eaten 1080 contaminated possum.[12]

The concentrations found in koura would require an 85kg adult to eat 2,840 small or 720 large koura tails to risk death.[13] Given that koura are nocturnal, and noting that 1080 leaches rapidly from baits in water, the baits would need to be dropped very close to koura shortly before nightfall . This is highly unlikely in a 1080 operation, further reducing any potential risk.[14]

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Studies of native and introduced freshwater fish have shown that fish are highly resistant to 1080, even when exposed in field trials to very high concentrations of 1080 in water and food. Read the facts here. Do 1080 baits in water harm fish? No.

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Interesting look at calcium retention for the moult.

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A couple of keen outdoors men, Ray Webb and Terry Arthur, touch base with the Natural Science team semi-regularly; we enjoy hearing about their adventures in wild places around Otago.

Image: Loganburn Reservoir | Astrid Erasmuson

Last year they had a successful day brown trout fishing at Loganburn Reservoir, part of the upper tributary of the Taieri River, high in the Lammermoor Range. Terry bagged a five pound (2.2 kg) brown trout, and as they gutted and prepared the fish they found some interesting stomach contents.

Stomach contents of a large trout, caught by Terry Arthur | Image: Ray Webb

The trout had recently made a meal of at least two large freshwater crayfish - southern kōura ( Paranephrops zealandicus). But it wasn't the presence of the kōura that surprised Ray and Terry; they had seen crayfish inside trout bellies before. Trout are a major predator of freshwater kōura.

What had hooked Terry and Ray's curiosity was the two little "poached quail egg-looking things" and they wrote to ask what these were, suspecting they had something to do with the crayfish rather than the trout.

Their suspicions were correct. These white dome button-shaped objects are a type of gastrolith found inside freshwater crayfish.

Kōura exoskeletons are made primarily of chitin and calcium carbonate, and the latter gives the shells their toughness. For kōura to grow larger, they must moult their tight older shells. A new soft exoskeleton one-size larger grows underneath and requires calcium carbonate to harden once the old one has been lost. Freshwater environments have low levels of dissolved calcium in the water, and kōura form gastroliths in their heads to store reserves of calcium carbonate in the lead-up to a moult.

Video: Ottdurr | YouTube | 4 November 2014. A white gastrolith can be seen through the translucent shell behind the eye.

There have been previous reports of freshwater kōura gastroliths showing up in the stomach contents of trout and shags. Vulnerable during their moult event, 'soft shell' kōura would make easy pickings.

Animal Attic displays southern kōura (centre) and gastroliths (right) | Image: Otago Museum

Kōura are endemic to New Zealand, and shortfin and longfin eels are their natural predators. The eel's skin mucus has a chemical cue that kōura can detect then avoid the eel by hiding. They are not able to detect trout in the same way, which makes them an easy target for these introduced predators.

In New Zealand's freshwater ecosystems, trout are tenacious and opportunistic predators. They feed on native fish - young eels, galaxiid (whitebait) species and bullies, as well as invertebrates like water snails and insects. There are even reports of mice being found in trout's bellies!

Fancy flies! | Otago Museum

Happy trout fishing when the season kicks off this week!

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A couple of keen outdoors men, Ray Webb and Terry Arthur, touch base with the Natural Science team semi-regularly; we enjoy hearing about their adventures in wild places around Otago. Image: Loganburn Reservoir | Astrid Erasmuson Last year they had a successful day brown trout fishing at Loganburn Reservoir, part of the upper tributary of the Taieri River, high in the Lammermoor Range.

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2019 was another busy and rewarding year for Te Wai Māori Trust. As we head into 2020, we thought we'd share our highlights from this year: Developing our policy responses with Iwi and hapū input [...]

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Welcome to Te Wai Māori the Māori Freshwater Fisheries Trust Te Wai Māori was established under the Maori Fisheries Act 2004 to advance Māori interests in freshwater fisheries. We are a part of the Māori Fisheries Settlement and it's our role to advance Māori interests in freshwater fisheries.

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Farming freshwater crayfish with forestry.

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Explore tikanga related to mahinga kai.

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The Waikato-Tainui relationship with the river is closely bound with the Kīngitanga and the Pai Mārire faith that King Tāwhiao brought back from Taranaki. Tikanga is a series of rules that are passed down from tūpuna (ancestors) and give Waikato-Tainui (and others) a basis for respecting the river, its resources and the environment. The purpose of tikanga is to find balance with and to protect the natural world of which we are all part.

The Kīngitanga is significant to Waikato-Tainui practices regarding the river. For Waikato-Tainui, the marae on the river are the centres of Waikato-Tainui communities that support the Kīngitanga and its values. Their histories continue to link them to the river and the Kīngitanga. Many Waikato-Tainui marae carry the names of the Kīngitanga and continue to celebrate poukai - gatherings that Tāwhiao began in 1884 to symbolise the importance of the relationship between the Kīngitanga and the marae.

Waikato-Tainui children have been raised to respect the river as a tupuna. Children were taught not to play in the river where taniwha (guardians) were known to appear. If they saw a taniwha making its way upstream, children were told to get out and sit on the bank to pay it respect.

In a similar way, tikanga taught people that the river was not to be polluted.

"We were taught not to mistreat the River by putting rubbish in it. My grandmother used to liken putting rubbish in the River to having rubbish being put in your own mouth."
(Statement of Evidence of Iti Rawiri, prepared for Anchor Hearing in the Environment Court, Appeal RMA 662/97, April 1998)

Tikanga also determines how fishing was to be conducted. For example, the first catch of every season is returned to the river, even if the net is full.

"That's for them, the tūpuna: that's your koha (thanksgiving) to them."
(Iti Rawiri, Oral History, 8 December 1998 cited in Parsonson, 1998)

Fish were allowed to die with dignity, and so they are not cooked straight from the river. Eels are also given respect in that they are not speared or disturbed while they are feeding.

When fishing, the tikanga is to only take what was needed. Often kaumātua will still caution fishers to only take what is needed and to not be greedy with food.

For marae, their mana is closely linked to kai. Marae have their own speciality foods. For example, for Tūrangawaewae, it was tuna (eel), for Horahora, it was kaeo (freshwater pipi), and for Tauranganui, it was matamata (whitebait).

Other resources are also important. Meat from freshwater kōura (crayfish) was sometimes used to rub on the gums of babies to help with teething. When it was used for this purpose, it was not used for eating. Watercress is used for food, raupō (reeds) were used for building houses and kiekie and harakeke (flax) are used for weaving clothing and whāriki (mats). These could be gathered from along the banks of the rivers and streams or from islands in the river.

Over time, constant human contact and a disrespect of the river has led to the decline of the health and wellbeing of the river. This has had an effect on the ability of marae to provide for their manuwhiri, and in turn, it affects their mana.

Some hapū and whānau put rāhui (restrictions on use) over certain times of the year to help fish stocks to replenish. Other practices include whānau letting others know when they are fishing so that a particular area of the river is not overfished. In some areas, such as Waahi Stream, different whānau had their own places where they would set their hīnaki (traps) for tuna, and in the lower parts of the river, different whānau had their own bench to set their net for whitebait. Tikanga would set the expectation that whānau rights would not be interfered with.

Rāhui can also be used to respect a death that has happened in the river.

Tikanga relating to childbirth involved newborn babies being taken to the river and being washed. This created a link between the life force of the river and the child so that they were one.

The river is also acknowledged as having healing qualities.

"[H]e waiora, he wai manaaki i te tangata, he wai whakaora i te tangata.
(The River is life-giving, the River nurtures the people, the River heals those who are sick.)"
(John Haunui, Oral History, 7 December 1998 cited in Parsonson, 1998)

Many people today still speak of the healing properties of the river. Many people from along the river have their own stories and experiences about the healing qualities of the river.

Acknowledgement

Copyright: Waikato-Tainui Endowed Colleges Trust.

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The Waikato-Tainui relationship with the river is closely bound with the Kīngitanga and the Pai Mārire faith that King Tāwhiao brought back from Taranaki. Tikanga is a series of rules that are passed down from tūpuna (ancestors) and give Waikato-Tainui (and others) a basis for respecting the river, its resources and the environment.

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This article provides an opportunity for students to differentiate between observation and inference. It draws on both traditional Māori knowledge and modern technologies to find out more about kōura.
Adapting the resource

Show the students the picture of the kōura on pages 18 & 19 but hide the text. (You might like to enlarge the photo or print copies so students can look closely at the photo). Ask the students to look closely at the kōura and describe what they can see. You may need to prompt them. For example:

How many legs can you see? What do they look like?

Look very carefully at the big front legs. Do they look smooth or rough? Are they straight or bendy?

What colour is the kōura?

Look at the tail. How many bits (segments) can you see?

What do its eyes look like? What do the long feelers look like?

Look carefully at the face and head. What do you see?

What is the body covered with?

In this initial activity discourage students from making inferences - just get them to describe what they can see.

Now ask the students the question in the first paragraph of the article, "How do you think a kōura might move around?

If the students say "the kōura walks" ask...

If the students say "the kōura swims" ask...

What makes you think so?

What makes you think so?

In answering these questions, students are making meaning based on their observations, i.e., they are thinking about what they see (interpreting data).

1. Now ask students to look carefully at the pincers and ask:
What do you think these are for? Prompt the students to elaborate on their answers, backing up their ideas with evidence (this could be what they can see in the photo or prior knowledge).

2. On page 21 there is a photo of a kōura being measured. Get the students to look closely at the photo and ask:

What can you see?

Why might it be important to measure the kōura?

3. Page 22 describes a variety of ways scientists tried to count kōura. Ask:
Why do you think the scientists wanted to know how many kōura there were?

This article contains the answers to these questions but focus on how the students justify their ideas, rather than on what the text says.

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Counting Kōura / Gather & interpret data / Introducing five science capabilities / Science capabilities for citizenship / Home - Science Online

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This article provides an opportunity for students to differentiate between observation and inference. It draws on both traditional Māori knowledge and modern technologies to find out more about kōura. Adapting the resource Show the students the picture of the kōura on pages 18 & 19 but hide the text.

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Possible achievement objectives

New Zealand Curriculum: Draft for Consultation, 2006
Nature of Technology

Characteristics of technology (Levels 1-2)

Characteristics of technological outcomes (Levels 1-2)

Technological Knowledge

Technological products (Levels 1-2)

Possible Technological Areas (TechiNZC)
Materials Technology Structures and Mechanisms
The speciﬁc learning intentions

Students will be able to:

identify and describe the attributes that animal traps need in order to be successful (Nature of Technology - Characteristics of technological outcomes, levels 1-2)

identify the materials used in traps and understand the performance properties of these materials (Technological Knowledge - Technological products, levels 1-2)

understand that people develop traps for speciﬁc purposes and that traps enhance people's ability to control living things (Nature of Technology - Characteristics of technology, levels 1-2)

describe and understand the relationship between the physical and functional attributes of traps (Nature of Technology - Characteristics of technological outcomes, levels 1-2)

The key ideas

Nature of Technology

The scientists tried many ways to count the kōura before ﬁnding a solution that worked.

As the scientists developed their solution, key attributes became important. For example, the method had to be economical and usable in rough and muddy water. It was also important that the traps did not get tangled with weeds and that the traps caught kōura of all sizes.

The tau kōura was developed by Māori as a way to collect and store kōura alive - by enticement rather than physical capture. In this way, they could control the kōura and harvest them when needed.

The tau kōura had crucial physical attributes. They looked like twisted roots and were made of ferns tied into bundles. The tau kōura were similar to the places where kōura hide in their natural environment. The matted fern also trapped food for the kōura to eat.

Technological Knowledge

The purpose of the tau kōura was to collect and store kōura. The properties of the natural materials used to construct the traps improved the performance of the trap.

Developing the ideas

The following NIWA Science web pages provide further information about the way in which existing technology was trialled and new outcomes were developed during the kōura study:

The New Zealand Clearwater Crayfish website provides information about the technology and animal husbandry techniques used for farming kōura.

Further activities

The activities below are designed to help students to discuss and practically investigate key ideas about the technology of traps:

Activity: All sorts of traps
What you need
Examples of or print/Internet photographs/illustrations of various traps, for example, a crayfish pot, possum cage, mousetrap, Venus ﬂytrap, pitcher plant, snail trap, ﬂy paper, whitebait net, minnow trap, butterﬂy net, roach hotel
What you do

Show the collection of photographs or devices to the students.

Ask them to tell you which of the traps are not an example of technology. (The Venus ﬂytrap and pitcher plant are both traps but are not technology because they haven't been designed by people. Their characteristics are, however, similar to those of traps made by people.)

Ask them to help you describe the physical attributes of the traps.

Record their observations on the board under the following headings: materials, size, and shape.

Discuss the possible purpose of each trap.

For each example, ask the students to make a reasoned prediction about the sort(s) of animal it might be designed for.

Conﬁrm or correct the students' predictions about the target animals and lead a discussion about how each trap might work.

In particular, ask the students to comment on links between the physical attributes of each trap and the way it functions. For example, the pitcher plant's tube is lined with downwardly angled hairs and some eel traps have barbs angled inwards along their entry tube. Both features allow the target animal to enter but prevent it from leaving. (These features will probably not be visible in illustrations, so you could mention them at the beginning as an example.)

Classify the traps in terms of how they operate to either trap and kill or trap and store the target animal.

This could lead into a discussion about how each trap fulﬁls a human or social need, for example, to provide food (in the case of the whitebait trap), to protect the environment (in the case of the possum trap), or to learn about nature (in the case of the tau kōura used in the article).

What you look for

Do the students realise that a trap is a technological outcome because it is developed and made by people?

Can the students describe the physical attributes of the traps?

Can they relate those physical attributes to the way in which each trap functions?

Activity: Making a trap to count slaters

This activity could be integrated with a simple science unit. However, the learning experiences below emphasise the characteristics of technology and of technological outcomes. The key attributes of slaters and their preferred environments need to be established before beginning the activity. For ideas that establish a scientiﬁc context, see Soil Animals, Book 6 in the Ministry of Education's Building Science Concepts series.
What you need

Potatoes

Rubber bands

Tools for hollowing out potatoes

What you do

Establish the need. For example, "As part of our study on mini-beasts, we need to work out where slaters like to live. We'll need some technology to help with our science study, so we're going to make some traps to capture slaters in various places. This will give us an idea of where they like to live."

Spend a little time discussing the purpose of the traps they're about to make.

The purpose is to capture and hold the slaters alive. This will allow the students to count the slaters (in order to answer the scientiﬁc question) and then release the animals.

You could reiterate some of the alternative purposes for traps.

The students should then make their potato traps by following these steps:

Cut the potato in half.

Hollow it out and make a hole in one end through which slaters can enter.

Put the halves back together and fasten them with rubber bands.

Locate the traps in different positions around the school grounds.

Return to the traps after a day or two, count the number of slaters inside, and release them in a dark, damp place.

Lead a discussion in which the students comment on the way in which the slater traps were designed to catch particular animals and hold them without harming them.

What you look for

Can the students accurately describe the physical attributes of the potato trap?

Can they relate those physical attributes to the trap's function?

Do they describe how the potato trap works in terms of the relationship between a slater's habitat and the physical attributes of the potato trap?

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Nature of Technology Characteristics of technology (Levels 1-2) Characteristics of technological outcomes (Levels 1-2) Technological Knowledge Technological products (Levels 1-2) Materials Technology Structures and Mechanisms Students will be able to: identify and describe the attributes that animal traps need in order to be successful (Nature of Technology - Characteristics of

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This article will raise questions over value - at what point does Western Science value indigenous knowledge?

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When it supports their claims, Western scientists value what Traditional Knowledge has to offer. If not, they dismiss it

smithsonianmag.com

Our knowledge of what animals do when humans aren't around has steadily increased over the last 50 years. For example, we know now that animals use tools in their daily lives. Chimps use twigs to fish for termites; sea otters break open shellfish on rocks they selected; octopi carry coconut shell halves to later use as shelters. But the latest discovery has taken this assessment to new heights-literally.

A team of researchers led by Mark Bonta and Robert Gosford in northern Australia has documented kites and falcons, colloquially termed "firehawks," intentionally carrying burning sticks to spread fire. While it has long been known that birds will take advantage of natural fires that cause insects, rodents and reptiles to flee and thus increase feeding opportunities, that they would intercede to spread fire to unburned locales is astounding.

It's thus no surprise that this study has attracted great attention as it adds intentionality and planning to the repertoire of non-human use of tools. Previous accounts of avian use of fire have been dismissed or at least viewed with some skepticism.

But while new to Western science, the behaviors of the nighthawks have long been known to the Alawa, MalakMalak, Jawoyn and other Indigenous peoples of northern Australia whose ancestors occupied their lands for tens of thousands of years. Unlike most scientific studies, Bonta and Gosford's team foregrounded their research in traditional Indigenous ecological knowledge. They also note that local awareness of the behavior of the firehawks is ingrained within some of their ceremonial practices, beliefs and creation accounts.

The worldwide attention given to the firehawks article provides an opportunity to explore the double standard that exists concerning the acceptance of Traditional Knowledge by practitioners of Western science.

Traditional Knowledge ranges from medicinal properties of plants and insights into the value of biological diversity to caribou migration patterns and the effects of intentional burning of the landscape to manage particular resources. Today, it's become a highly valued source of information for archaeologists, ecologists, biologists, ethnobotanists, climatologists and others. For example, some climatology studies have incorporated Qaujimajatuqangit (Inuit traditional knowledge) to explain changes in sea ice conditions observed over many generations.

Yet despite the wide acknowledgement of their demonstrated value, many scientists continue to have had an uneasy alliance with Traditional Knowledge and Indigenous oral histories.

On the one hand, these types of knowledge are valued when they support or supplements archaeological, or other scientific evidence. But when the situation is reversed-when Traditional Knowledge is seen to challenge scientific "truths -then its utility is questioned or dismissed as myth. Science is promoted as objective, quantifiable, and the foundation for "real" knowledge creation or evaluation while Traditional Knowledge may be seen as anecdotal, imprecise and unfamiliar in form.
Ways of Knowing
Are Indigenous and Western systems of knowledge categorically antithetical? Or do they offer multiple points of entry into knowledge of the world, past and present?

There are many cases where science and history are catching up with what Indigenous peoples have long known.

For instance, in the past two decades, archaeologists and environmental scientists working in coastal British Columbia have come to recognize evidence of mariculture-the intentional management of marine resources-that pre-dates European settlement. Over the course of thousands of years, the ancestors of the Kwakwaka'wakw and other Indigenous groups there created and maintained what have become known as "clam gardens"-rock-walled, terrace-like constructions that provide ideal habit for butter clams and other edible shellfish.

To the Kwakwaka'wakw, these were known as loxiwey, according to Clan Chief Adam Dick (Kwaxsistalla) who has shared this term and his knowledge of the practice with researchers. As marine ecologist Amy Groesbeck and colleagues have demonstrated, these structures increase shellfish productivity and resource security significantly. This resource management strategy reflects a sophisticated body of ecological understanding and practice that predates modern management systems by millennia.

These published research studies now prove that Indigenous communities knew about mariculture for generations-but Western scientists never asked them about it before. Once tangible remains were detected, it was clear mariculture management was in use for thousands of years. There is a move underway by various Indigenous communities in the region to restore and recreate clam gardens and put them back into use.

A second example demonstrates how Indigenous oral histories correct inaccurate or incomplete historical accounts. There are significant differences between Lakota and Cheyenne accounts of what transpired at the Battle of Greasy Grass (Little Big Horn) in 1876, and the historical accounts that appeared soon after the battle by white commentators.

The Lakota and Cheyenne can be considered more objective than white accounts of the battle that are tainted by Eurocentric bias. The ledger drawings of Red Horse, a Minneconjou Sioux participant in the battle, record precise details such as trooper's uniforms, the location of wounds on horses, and the distribution of Indian and white casualties.

In 1984, a fire at the battleground revealed military artifacts and human remains that prompted archaeological excavations. What this work revealed was a new, more accurate history of the battle that validated many elements of the Native American oral histories and accompanying pictographs and drawings of the events. However, without the archaeological evidence, many historians gave limited credence to the accounts obtained from the participating Native American warriors.
Opportunities at the Intersection
Hypotheses incorporating traditional knowledge-based information can lead the way toward unanticipated insights. The travels of Glooscap, a major figure in Abenaki oral history and worldview, are found throughout the Mi'kmaw homeland of the Maritime provinces of eastern Canada. As a Transformer, Glooscap created many landscape features. Anthropologist Trudy Sable (Saint Mary's University) has noted a significant degree of correlation between places named in Mi'kmaw legends and oral histories and recorded archaeological sites.

As ways of knowing, Western and Indigenous Knowledge share several important and fundamental attributes. Both are constantly verified through repetition and verification, inference and prediction, empirical observations and recognition of pattern events.

While some actions leave no physical evidence (e.g. clam cultivation), and some experiments can't be replicated (e.g. cold fusion), in the case of Indigenous knowledge, the absence of "empirical evidence" can be damning in terms of wider acceptance.

Some types of Indigenous knowledge, however, simply fall outside the realm of prior Western understanding. In contrast to Western knowledge, which tends to be text-based, reductionist, hierarchical and dependent on categorization (putting things into categories), Indigenous science does not strive for a universal set of explanations but is particularistic in orientation and often contextual. This can be a boon to Western science: hypotheses incorporating traditional knowledge-based information can lead the way toward unanticipated insights.

There are partnerships developing worldwide with Indigenous knowledge holders and Western scientists working together. This includes Traditional Ecological Knowledge informing government policies on resource management in some instances. But it is nonetheless problematic when their knowledge, which has been dismissed for so long by so many, becomes a valuable data set or used selectively by academics and others.

To return to the firehawks example, one way to look at this is that the scientists confirmed what the Indigenous peoples have long known about the birds' use of fire. Or we can say that the Western scientists finally caught up with Traditional Knowledge after several thousand years.
George Nicholas, Professor of Archaeology, Simon Fraser University

This article was originally published on The Conversation.

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When Scientists "Discover" What Indigenous People Have Known For Centuries

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smithsonianmag.com Our knowledge of what animals do when humans aren't around has steadily increased over the last 50 years. For example, we know now that animals use tools in their daily lives. Chimps use twigs to fish for termites; sea otters break open shellfish on rocks they selected; octopi carry coconut shell halves to later use as shelters.

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Freshwater Fish: Koura (Freshwater Crayfish)

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Stella McQueen joins us once again. Tonight, everything you ever wanted to know about Koura (Freshwater Crayfish).