Scientists survey Taharoa eel populations
The survey team assessing eel stocks in four lakes around Taharoa take a break from the intensive field work. The research was brought about after local hapu Ngati Mahuta raised concerns about the state of customary eel stocks.
 The survey team assessing eel stocks in four lakes around Taharoa take a break from the intensive field work. The research was brought about after local hapu Ngati Mahuta raised concerns about the state of customary eel stocks. |
Ian Ruru of Te Aitanga a Mahaki and a former Te Ohu Kaimoana scholar is leading a survey of four lakes around Taharoa, south of Kawhia to survey eel populations.
In 2002, his company Maumahara Consultancy Services Ltd secured the first of several competitively tendered customary research projects offered by the Ministry of Fisheries after the company became a registered research provider.
The research was brought about after local hapu Ngati Mahuta raised concerns about the state of customary eel stocks in the lakes and sought a scientific perspective.
Ian Ruru, a fisheries scientist, says that our freshwater eels spawn and die near Tonga or Samoa and then their offspring return to New Zealand rivers, waiting up to 100 years before returning to the spawning grounds. Information gained from these surveys, such as how fast they grow and mature, will be used to better understand and manage factors that have an effect on the population status.
Eels are aged through analysing the growth rings from their otoliths (ear bones). Each year, a new ring is formed on the tiny bones and by counting the rings, scientists can determine the age of the eel. This data is critical to help determine what is occurring with the population in those lakes.
“The results show a crisis point for the customary eel fisheries in Taharoa,” he says.
There has been little annual recruitment into the Taharoa lakes because of an inadequate and inefficient fish pass installed in the 1970s to allow fish to pass the dam. This is evident from the absence of eels of both species under 300mm and the drop in catch rates.
 |
Members of
the Waipaoa
River Team, Ben
Chisnall, Ronni
Symon, Jane
Goodman, Ian
Ruru and Bill
Ruru (front),
take a break
from activities. |
Ngati Mahuta has been proactive in driving the need for the survey of their customary taonga. The fate of these lakes ultimately depends on co-operative management initiatives that include fisheries enhancement programmes that look to rebuild longfin eel stocks as well as the other native fish species that were once abundant at Taharoa.
Ian says his approach to fisheries research is unique. In addition to providing scientifically robust assessments of the status of fish stocks, he empowers the tangata kaitiaki to better understand their aquatic environment. “The success of this business is put down to the principle of Kaitiakitanga,” he says.
Ministry of Fisheries annually invites tenders for required research from registered research providers. In 2002, Ian received Te Ohu Kaimoana and Seafood Industry Training endorsement to register as a provider. “Robin Hapi (former CEO) supported the idea of a Te Ohu Kaimoana scholar branching out into the research business and Barbara Johnsen (former SITO CEO) could see the need to develop NZQA unit standards to support customary fishing,” Ian says.
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Protecting Māori fisheries assets for future generations