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Longfin Eel (Tuna) at Te Waihora Lake Ellesmere
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TitleLongfin Eel (Tuna) at Te Waihora Lake Ellesmere
DescriptionTe Waihora has almost 50 fish species recorded in the lake. Along with pātiki (flounder), īnanga (whitebait), and aua (yellow-eyed mullet) tuna (longfin eels) are significant mahinga kai species for Ngāi Tahu.
The longfin eel (tuna) or Anguilla dieffenbachii, is a remarkable fish, one of three species of Anguilla found throughout the lakes and waterways of Aotearoa New Zealand.
Across the district, tuna live in Te Waihora Lake Ellesmere as well as its rivers and streams. The longfin eel is an iconic species and is highly valued for recreational and cultural purposes.
The longfin eel is named because its top (dorsal) fin is longer than its bottom fin. Dark brown to grey-black in colour, they are one of largest eels in the world, growing up to one metre long and weighing up to 10kg.
Eels eat live food, starting with insect larvae, worms and water snails. As they mature, they feed on fish, along with fresh-water crayfish and even small birds such as ducklings. They hunt nocturnally, using their strong sense of smell, with nostrils that protrude from the front of their head, above their upper lip.
During the day, tuna are secretive, preferring to live in covered habitats. They can live for up to 106 years and reach maturity around the age of 33. They breed only once before they die, in a unique lifecycle.
After 25-80 years, living in rivers, lakes and wetlands, they travel 5000km to the South Pacific near Tonga to breed. After laying their eggs, they die. The tiny fertilised eggs float on ocean currents for about 15 months until they reach New Zealand. As the eggs transform into glass eels and then elvers to adult eels, they journey inland, swimming up rivers, over waterfalls, and even crawling over dams, as they can travel overland for up to two days by breathing through their skin.
The ancestors of modern New Zealand eels, like tuna, had been swimming up and down New Zealand waterways since at least the early Miocene period (23 million years ago). According to the Department of Conservation, although relatively common, longfin eels are now considered to be 'at risk, declining'.
Tuna have been commercially fished in Te Waihora since the mid 1900s. An export deal struck in the 1970s meant that large quantities of tuna from Te Waihora – up to 800 tonnes in a year – was exported to London, to make the historic East End delicacy of jellied eels.
During the 1970s and early 1980s, such large quantities of tuna were caught, that they progressively reduced the average size of eels in the lake. This had a profound impact on the customary fishing practices of Māori, which are based on allowing the animals to reach a larger size before harvesting. In 1978 Te Waihora was declared a controlled fishery for tuna, with catches limited, and a quota management system was introduced in 2000 for tuna and flounder in the lake.
The Te Waihora tuna fishery is restricted to shortfin eels, with longfin eels released. The quota area covers the catchments north of the Rakaia River to Te Waihora, although almost all the catch is from Te Waihora. The current allowable commercial catch for tuna is 122 tonnes each year, mainly caught between October and March.
In addition to over-fishing, the other contributing factor to the well-being of mahika kai species at Te Waihora were the changes brought about by European farming practices from the 1850s, following the contested sale of Ngāi Tahu land across Canterbury through the Kemp Deed in 1848. The drainage of wetlands and the introduction of livestock and fertilisers played a key role in decreasing the health of Te Waihora as a habitat. A quote on the Te Waihora co-governance website contrasts the former health and clarity of the lake with that after land reclamation and agricultural intervention by settlers:
'There was a time when pātiki/flounder could be seen swimming above the shingle lake bottom – a time when tuna/eels were so plentiful the creeks stirred, slippery and black; and plant life grew abundant and rich. It was a time of balance and health. Decades of settlement and farming though, have taken their toll and the lake has been significantly polluted.'
Awareness of this has generated a significant increase in the number of organisations and community groups actively invested in improving the environmental health of Te Waihora and its tributaries. Alongside Environment Canterbury, Manaaki Whenua Landcare Research, Lincoln University and the Department of Conservation Te Papa Atawhai, a network of local groups actively cares for the environment, including Te Taumutu Rūnanga, Te Ara Kākāriki, and Ellesmere Sustainable Agriculture.
DescriptionTe Waihora has almost 50 fish species recorded in the lake. Along with pātiki (flounder), īnanga (whitebait), and aua (yellow-eyed mullet) tuna (longfin eels) are significant mahinga kai species for Ngāi Tahu.The longfin eel (tuna) or Anguilla dieffenbachii, is a remarkable fish, one of three species of Anguilla found throughout the lakes and waterways of Aotearoa New Zealand.
Across the district, tuna live in Te Waihora Lake Ellesmere as well as its rivers and streams. The longfin eel is an iconic species and is highly valued for recreational and cultural purposes.
The longfin eel is named because its top (dorsal) fin is longer than its bottom fin. Dark brown to grey-black in colour, they are one of largest eels in the world, growing up to one metre long and weighing up to 10kg.
Eels eat live food, starting with insect larvae, worms and water snails. As they mature, they feed on fish, along with fresh-water crayfish and even small birds such as ducklings. They hunt nocturnally, using their strong sense of smell, with nostrils that protrude from the front of their head, above their upper lip.
During the day, tuna are secretive, preferring to live in covered habitats. They can live for up to 106 years and reach maturity around the age of 33. They breed only once before they die, in a unique lifecycle.
After 25-80 years, living in rivers, lakes and wetlands, they travel 5000km to the South Pacific near Tonga to breed. After laying their eggs, they die. The tiny fertilised eggs float on ocean currents for about 15 months until they reach New Zealand. As the eggs transform into glass eels and then elvers to adult eels, they journey inland, swimming up rivers, over waterfalls, and even crawling over dams, as they can travel overland for up to two days by breathing through their skin.
The ancestors of modern New Zealand eels, like tuna, had been swimming up and down New Zealand waterways since at least the early Miocene period (23 million years ago). According to the Department of Conservation, although relatively common, longfin eels are now considered to be 'at risk, declining'.
Tuna have been commercially fished in Te Waihora since the mid 1900s. An export deal struck in the 1970s meant that large quantities of tuna from Te Waihora – up to 800 tonnes in a year – was exported to London, to make the historic East End delicacy of jellied eels.
During the 1970s and early 1980s, such large quantities of tuna were caught, that they progressively reduced the average size of eels in the lake. This had a profound impact on the customary fishing practices of Māori, which are based on allowing the animals to reach a larger size before harvesting. In 1978 Te Waihora was declared a controlled fishery for tuna, with catches limited, and a quota management system was introduced in 2000 for tuna and flounder in the lake.
The Te Waihora tuna fishery is restricted to shortfin eels, with longfin eels released. The quota area covers the catchments north of the Rakaia River to Te Waihora, although almost all the catch is from Te Waihora. The current allowable commercial catch for tuna is 122 tonnes each year, mainly caught between October and March.
In addition to over-fishing, the other contributing factor to the well-being of mahika kai species at Te Waihora were the changes brought about by European farming practices from the 1850s, following the contested sale of Ngāi Tahu land across Canterbury through the Kemp Deed in 1848. The drainage of wetlands and the introduction of livestock and fertilisers played a key role in decreasing the health of Te Waihora as a habitat. A quote on the Te Waihora co-governance website contrasts the former health and clarity of the lake with that after land reclamation and agricultural intervention by settlers:
'There was a time when pātiki/flounder could be seen swimming above the shingle lake bottom – a time when tuna/eels were so plentiful the creeks stirred, slippery and black; and plant life grew abundant and rich. It was a time of balance and health. Decades of settlement and farming though, have taken their toll and the lake has been significantly polluted.'
Awareness of this has generated a significant increase in the number of organisations and community groups actively invested in improving the environmental health of Te Waihora and its tributaries. Alongside Environment Canterbury, Manaaki Whenua Landcare Research, Lincoln University and the Department of Conservation Te Papa Atawhai, a network of local groups actively cares for the environment, including Te Taumutu Rūnanga, Te Ara Kākāriki, and Ellesmere Sustainable Agriculture.
Connections
CollectionThe Creation of TunaMahika kai species of Te WaihoraImagePatu tunaMapMap of the major waterways of Te Waihora catchmentMore InformationRead about the longfin eel on the Department of Conservation websiteRead about the longfin eels at Auckland ZooRead about the longfin eel at the NIWA websiteRead about the longfin eel at the Te Waihora Co-governance website
Mahika kai species of Te WaihoraImagePatu tunaMapMap of the major waterways of Te Waihora catchmentMore InformationRead about the longfin eel on the Department of Conservation websiteRead about the longfin eels at Auckland ZooRead about the longfin eel at the NIWA websiteRead about the longfin eel at the Te Waihora Co-governance websiteAttribution
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Longfin Eel (Tuna) at Te Waihora Lake Ellesmere. Selwyn Stories, accessed 25/06/2026, https://selwynstories.selwynlibraries.co.nz/nodes/view/6200