The lifecycle of the glass eel and its migration to Aotearoa remains a mystery but it's one NIWA scientists and iwi in Whakatane are trying to find answers for and investigate the impact climate change and water quality has on this species as it transfers from the sea to freshwater.
Dr Eimear Egan from Niwa says important information that is stored in the eels' six ear bones plays a vital part in understanding them.
“Fish have six ear bones in their head, three on either side. They are also considered a fish's diary because a lot of information is recorded on that ear bone. Information such as their birthday, age and growth rates are really important properties. The chemistry of the water that a fish has been living in is absorbed and recorded on those ear bones.”