Longfin eel - Alton Perrie

Longfin Eel / Tuna

Photo courtesy of Alton Perrie

It’s no wonder tuna are considered a taonga (treasure), having graced lakes, swamps, rivers and streams for more than 23 million years. Female longfins, as they’re commonly known, reach breeding maturity at anywhere up to 100 years of age. Only once in their life will they travel to Tonga to breed and then die. A range of pressures have had a significant impact on longfin numbers over the past fifty years, resulting in tuna now being classified as ‘at risk’.  Fishing has led to significant stock reductions in many areas, and a marked decline in the average size of the eels caught. Further pressures include pollution, habitat loss caused by hydro development, drainage and irrigation schemes and river diversions. Poor understanding of the species has led to negative human-eel interactions and general disregard for the important role this species plays in freshwater ecosystems. The survival of this species is intricately linked to healthy waterways. Riparian planting, weeding, pest control, advocacy and education are actions that will help secure a healthy, predator-free wild future for longfins.

Species: Tuna / Longfin Eel / Anguilla dieffenbachii
Location: New Zealand, endemic
Status: At Risk, Declining
Threats: Habitat loss and degradation, barriers to migration, pollution and high nutrient levels reducing oxygen levels are all threats to survival.
Our work: Habitat restoration and improvement, monitoring, ‘steam-scaping’

Description and distribution

Longfins have an elongate, slender body that is almost tubular in shape. They are usually dark brown to grey black in colour, and very occasionally, bright yellow. Tiny scales are embedded deeply within their thick, leathery skin. The eel’s skin is very sensitive to touch, helping them to “see” in their watery environment. Incredibly, their head shape changes drastically throughout their life depending on their lifestyle.

Longfins can be found throughout New Zealand, living mostly in rivers and inland lakes. However, they can also be found well inland due to their incredible climbing skills. Elvers (young eels) can climb waterfalls and dams by wriggling over damp areas, even leaving the water to do so.  Eels are known to climb as high as 20 metres up waterfalls.

Help save the Longfin eel

You can be a part of important projects by volunteering to help the longfin eel or donating to our Wild Futures program to ensure their survival. Conservation Volunteers New Zealand is working with the Department of Conservation mobilising and connecting people with nature, making it easy for people to make a difference and help secure longfin eel populations in the wild.

We have urgent need of support for several practical conservation activities linked to the protection and enhancement of longfin eel habitat including:

  • Removal of invasive weed species along rivers, streams, swamps and lakes.
  • Riparian planting
  • Monitoring
  • Creation of in-stream habitat

Your financial assistance or hands-on help in these endeavours will allow these longfin eels to increase in numbers in their natural habitat ensuring that this valued taonga have a Wild Future.

Together we can make a difference … 

We need your continued support to safeguard the survival of longfins and their habitats along with other species across the country.


Would you like to give the longfin eel a Wild Future? You can do so by donating through our secure online system.


By volunteering on one of our field projects, you can make a practical contribution and help give the longfin eel a Wild Future.

Educational Resources

Thanks to generous funding from Mobil Oil New Zealand Limited, we have developed an educational resource for the longfin eel called, ‘Tamariki for Tuna’. You can access these resources here.


Further Information

View longfin eel on the Department of Conservation website. Click link to DOC page below.