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Tuna | Longfin Eel

Join us to safeguard the endangered tuna, the longfin eel, here in Aotearoa. A taonga species, the tuna is at risk of extinction due to habitat loss, pollution, commercial fishing, and hydro development.

Despite being classified as endangered by the IUCN, 250 tonnes of these remarkable eels are still allowed to be fished each year with commercial catch making up 137 tonnes. We must act now to protect their future.

Quick facts

  • Tuna (fresh water eels) are an important part of New Zealand's freshwater ecosystems, with two main types - the shortfin and the longfin.

  • Tuna are a taonga species, and are central to the identity and wellbeing of many Māori. For generations these species have sustained communities and helped transfer customary practices and knowledge from one generation to the next. However, many communities are reporting that both the abundance and size of these freshwater taonga is decreasing. Longfin eels are considered at risk of extinction and are declining in numbers.

  • The longfin eel is the largest freshwater eel in New Zealand and is the only endemic species, with the other eels being the native shortfin eel and the naturally introduced Australian longfin eel.

  • Longfin eels are long-lived, with females reaching up to 106 years old and weighing up to 24kg.

  • Their slow growth rate of just 1-2 centimetres a year makes them vulnerable to overfishing. Longfin eels migrate to the Pacific Ocean near Tonga to breed at the end of their lives, making a journey of thousands of kilometres.

  • The small larvae,  known as "glass eels" can take up to two years to return to New Zealand waters, during the spring whitebait season.

Loss of Habitat

There has been a decline in eel populations due to the loss of wetlands, drainage, hydro development, irrigation schemes and river diversions. Culverts and dams impede or prevent their migration. Water pollution also affects eels. Sewage, toxins and effluent discharged into rivers and nutrients leaching from soils into waterways can result in large quantities of oxygen being removed from the water. The result of this oxygen depletion is that the eels will either die or move away[1]. In 2013, it was discovered that native fish and tuna were using Wellington’s stormwater system as access between streams and the sea[2]. Eels prefer habitats with plenty of cover and are mainly nocturnal and secretive.

Longfin Eel Tuna

Native fish and tuna have been discovered using Wellington’s stormwater system as access between streams and the sea

Commercial fishing

  • Longfin eels are commercially fished, despite being classified as "Endangered" by the IUCN. The New Zealand government continues to allow the export of tuna and the commercial eel fishery is managed by the Ministry for Primary Industries under the Quota Management System. The total allowable catch for longfins is around 250 tonnes per year and it's estimated around 130 tonnes of the eel is caught every year for commercial and export purposes.
  • Commercial fishing has had a significant impact on the species, with significant stock reductions in some areas and a marked decline in the average size of the eels caught. They don’t breed until they migrate to the ocean, so all the ones killed for export were yet to breed.
Longfin Eel Tuna

Tuna are as threatened as the North Island brown kiwi and Moana Fisheries an iwi-owned fishing company, is choosing not to fish them commercially due to sustainability concerns. However, the eeling industry continues to resist calls to ban commercial fishing of longfin eels.

  • In June 2012 it was reported that pet food companies were using the nationally threatened eels in their products, sparking outrage by conservationists. Scientists and conservation groups have growing concern for the survival of the species, as they can be legally killed and have a slow reproduction rate, breeding only once at the end of their lifetime. The 2018 IUCN assessment noted a sharp decline in longfin numbers over the last century, accompanied by significant reduction of habitat[1].

  • Moana New Zealand, the largest Māori-owned fishery in the country owns the right to catch 27 tonne of longfin eel. It chooses to sit on this right and not use it. A spokesperson said this was part of the company’s responsibility as kaitiaki of Aotearoa’s waters and the fishing of the eel was one of the concerns held for the species:

    “Moana New Zealand owns quota for both shortfin and longfin eels (tuna). Generally we consider shortfin tuna stocks are healthy and abundant, however our Iwi shareholders have said that they have some concerns about the long-term sustainability of longfin tuna stocks.[2]”

  • In mid-April 2013, the Parliamentary Commissioner for the Environment (PCE) Dr Jan Wright launched a report “On a pathway to extinction? An investigation into the status and management of the longfin eel”[3]. The report warns New Zealand that we need to stop commercial fishing of our native longfin eels (Anguilla dieffenbachia) or the species will face extinction.


What Needs To Be Done

  • Our new project "Drains are Streams," is dedicated to restoring waterways and habitats where tuna live.

  • By adopting a drain and improving stormwater management, we can safeguard our precious biodiversity.

  • Your donation will help us create resources, develop education programmes, and produce immersive videos to empower children and communities to take action.

  • Together, we can make a lasting impact and ensure a brighter future for both the tuna and our waterways.

Drains are Streams
Waiora - Streams

How can you help?

We are seeking donations to fund these initiatives so we can take immediate action to save the longfin eel. Every contribution, no matter the size, will make a meaningful impact on the future of this endangered species and the preservation of New Zealand's unique biodiversity.

Your financial support will directly fund our conservation efforts to engage wider communities with this issue and the solutions. Even a small contribution can go a long way in protecting the tuna and the fresh water ecosystems it needs to survive and thrive.

We Need Your Support Today!

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