Eels (Tuna) are seen by Māori as taonga (treasures) and ancestors, reminding us of our connection to nature and the importance of caring for it.

“Tuna" is the general Māori name for eels. There are three types of eels in Aotearoa New Zealand (NZ): longfin, shortfin, and Australian longfin.
Eels are often called "living fossils" because their body structure has remained largely unchanged for millions of years. We still don’t fully understand their evolution.

 

WHooTimaru Tuna Eel lifecycle

Tuna is a generic Māori word for freshwater eels. Māori have over 100 names for eels.

I LIVE: lakes and rivers connected to the sea.

I EAT: Small insects larvae, snails, midges and crustaceans. As our mouths get bigger, we can eat kōura (freshwater crayfish), fish, small birds and rats. When scared I bite!

Did you know: I’m the largest fish in Aotearoa freshwaters


There are three tuna species in NZ: The longfin eel, known as tuna, is one of the largest eels in the world.

LONGFIN EEL
(Anguilla dieffenbachii) Max size: 2m, 25kg

SHORTFIN EEL
(Anguilla australis) Max size: 1.1 metre, 3kg

AUSTRALIAN LONGFIN EEL
(Anguilla reinhardtii), Max size: 2 metres, 21kg

Tuna Eel lifecycle

 

My super power is:

  • I can swim 1000s km in the sea or fresh water.
  • Near the end of my life, I swim from NZ to the deep trenches near Tonga.
  • This is where I release eggs/sperm to spawn.
  • Over 10 months, my tiny larvae follow the ocean currents back to NZ.
  • They develop into transparent glass eels, and swim to rivers.
  • They turn greyish-brown and become elvers, to grow into strong adults in fresh water (rivers, lakes, wetlands). Then the swim back to sea and repeat our life cycle.

 

I help the eco system as a top predator and food source in the marine food chain and help balance the ocean environment.

I am a Taonga species central to the identity and well being of many Māori and are a significant mahinga kai (food).

 

Incredible Adaptations

  • Eels are born without a gender. They grow faster in areas with fewer eels and become females, while those in crowded, competitive environments grow slower and become males.
  • Eels are carnivores and use their teeth to eat insects, worms, fish, small birds, and even mice.
  • Although they rarely bite humans,if they do, it can result in a painful graze.
  • Before starting their long journey to the ocean to spawn, eels undergo dramatic body changes. Their heads flatten, and their eyes enlarge.

Mysterious Migration

  • Eels don’t rely on sight; instead, they follow invisible paths using environmental cues such as the Earth's magnetic field, temperature, and salinity.
  • During their journey, they cannot feed and rely solely on stored body fat for energy.
  • No one has ever seen eels reproduce in the wild. Scientists believe instinct guides longfin eels to the Tongan Trench and shortfin eels to waters near Samoa and Fiji.
  • They pass through the deep Kermadec and Tongan Trenches, where the Pacific Plate is sliding under the Australian Plate, creating the ideal deep-sea conditions for reproduction.

 

INCREDIBLE MIGRATION

Eels swim for 3–6 months from New Zealand to the deep ocean trenches west of Tonga to spawn—an epic journey of 5,000–6,000 km!

 

Fascinating Cycle

At the end of their lives, eels leave NZ to spawn near Tonga, Samoa, and Fiji.
Their fertilised eggs grow into larvae, which drift thousands of kilometres on ocean currents, eventually becoming 6–8 cm glass eels.
Near the shore, these glass eels grow into 10–15 cm elvers and move into streams, wetlands, and rivers, often returning to the very places where their mothers lived.
Eels can grow up to 1-2 metres long and live for over 100 years!
They then return to the sea as migrant Tuna Heke to begin the life cycle again.
Longfin eels are unique to NZ, and are among the largest eel species in the world!

Lost Habitat

Imagine arriving at your mother’s home after such a long journey, only to find the lagoon has disappeared and the creek is polluted.
Waimātaitai was once a 50-acre lagoon (hāpua) and eel weir (e rauiri) where Ashbury Park and the supermarket are today.
It was drained in 1933, leading to the loss of critical eel habitat. All that remains is a small creek, now connected to the sea by a 1.35 km stormwater drain.

 

NZMap Eel Map Timaru 1911 241218

 

Miscellaneous Plans - Borough of Timaru, South Canterbury. T.N. Brodrick, Chief Surveyor Canterbury. Held by: Archives New Zealand/Te Rua Mahara o te Kāwanatanga, Christchurch Regional Office - Archway Record Code: R25538727

 

Borough of Timaru South Canterbury 1948 nlnzimage Sourced from LINZ Crown Copyright reserved

Borough of Timaru South Canterbury-1948-nlnzimage-Sourced from LINZ - Crown Copyright reserved

 

How you can help

  • Feed eels only meat, no bones, eggs, or vegetables.
  • Stay out of the water and don’t throw stones.
  • Cover rubbish bins to prevent attracting pests and to stop rubbish blowing into the creek.
  • Improve water quality, ensure only rainwater enters stormwater drains. Wash your car on grass and use biodegradable detergents.

 

NZMap Eel Map 241218


Zealandia Te Riu-a-Māui

Is a mostly submerged continent in the southwest Pacific, with 94% underwater.
Its visible land includes New Zealand and New Caledonia.
To the north are the Kermadec and Tongan Trenches, where the Pacific Plate subducts beneath the Australian Plate, forming deep ocean trenches. Nearby Tonga and Fiji
are volcanic islands on the Pacific Plate.

 

2622 01 012A

J. S. Browning, (1831 – 1909), Timaru Looking North West, 1860, file copy print, Hocken Collections, Uare Taoka o Hākena, University of Otago.

 

Timaru Harbout General Chart Timaru Sir John Coode cropped

Timaru Harbour, Province of Canterbury : general chart of Timaru and adjoining coast by Sir John Coode showing works recommended by Sir John Coode, August 1875. (from Patiti Point to Washdyke Lagoon). The proposed works are shown by red colour. timdc.pastperfectonline.com/DCEC5B88-61FE-4949-80EC-525377755260

 

WuHooTimaru BlackMaps CoastlineChange

One of the ways you can investigate is visiting 9th Century Black Maps - Check out that huge lagoon and wetland that used to be where Washdyke industrial area is today... you can also see the Waimataitai wetland that used to be at Ashbury Park and the changes at Otipua Wetlands too! https://www.arcgis.com/apps/webappviewer/index.html?id=bec5eceea7514735b73bbe9e8082371f

 

CPlay Timaru Coastal Changes

Here you can see the Timaru Coastline, comparing the digitized survey maps (that were created 1848 - c.1870s) to 2022. The surveys were carried out for the legal purchase and sale of land parcels, initially under the administration of the Canterbury Association, which was founded in London 27 March 1848 in order to establish a Church of England settlement in New Zealand. The historic survey maps are a crucial source of information showing the Ngāi Tahu relationship with the landscape of Te Waipounamu. The Black Maps are fascinating objects that help bring to life the story of pākehā exploration and the development of Canterbury.  https://apps.canterburymaps.govt.nz/BlackMaps

This gives an insight into traditional areas of mahinga kai (sites of significance to Māori for food gathering) such as wetlands, lagoons, and estuaries before they were modified. - https://mapviewer.canterburymaps.govt.nz/?webmap=0db87348adef4595a91994a3dc85cefe&extent=1457673.4475%2C5078749.6304%2C1476018.3343%2C5087320.1322%2C2193