Kanakana (lamprey)
Pictured above: Kanakana (lamprey) found in the Te Hoiere catchment
Uncovering the presence of lamprey (kanakana) in the Te Hoiere catchment
Kanakana, or lamprey, are a taonga species with deep cultural and ecological significance in Aotearoa. Recognised for their ancient lineage and eel-like appearance, lamprey play an important role in both the freshwater and marine environments.
Once plentiful they now have the conservation status of Threatened - Nationally Vulnerable. As a mahinga kai species, there has been a renewed focus on determining the presence of lamprey populations to find out where they are and, in turn, work to protect both them and the habitats they need to complete their lifecycle.
With an elusive nature and secretive behaviour, lamprey are a tricky species to study, let alone find. To better understand and protect these species, a collaborative effort between the Department of Conservation, local iwi, and scientists is underway to detect their presence in the Te Hoiere catchment.
Lamprey are a unique fish in both their appearance and behaviour. Like whitebait they migrate up and down streams, spending some of their lifetime in the sea. In the ocean they act parasitically, sucking onto fish, sharks and whales with their toothed mouths, utilising their blood and body fluids for food.
As adults they appear sleek but lose their blue colouration when they return to our rivers and head upstream, often travelling over 100 kilometres. Here they stop feeding and fast for 12-18 months, remaining hidden beneath rocks, bedrock slabs or within river banks. A male and female will pair up in these hidden cavities within rivers and tributary streams where they will lay and fertilise their eggs. After spawning the adults will die several months later.
Project beginnings
The project to detect the presence of kanakana began in 2023 as part of a broader initiative to monitor and conserve freshwater taonga species in Te Hoiere. DOC and iwi partners identified kanakana as a priority species due to their cultural importance and declining populations. Supported by Ngā Awa funding, the project aims to gather baseline data on the presence of lamprey in the catchment to inform future conservation efforts.
Cultural and ecological significance
For Ngāti Kuia, lamprey are not only a valuable food source but also a tohu for the mauri (life force) of the waterways. Their presence reflects the overall health of the aquatic environment, making them a critical species for monitoring ecosystem changes. Lamprey have a unique lifecycle that spans both freshwater and marine stages, and they are known for their extraordinary migration, travelling thousands of kilometres to breed in freshwater streams like those in Te Hoiere.
Kanakana pheromone sampler indicated by a white tag in the Whakamarino.
Detection and monitoring efforts
Leading the charge on this project, Anna Henderson from DOC, alongside Dr Cindy Baker, a NIWA Principal scientist renowned for her expertise in pheromone sampling, have spearheaded the lamprey detection efforts. Dr Baker’s innovative use of pheromone samplers allows for the non-invasive monitoring of lamprey, making it easier to detect these elusive creatures.
This method involves immersing a small sampler (essentially an absorbent bag) in the middle of a stream and leaving it there for 2-3 weeks. During this time the sampler accumulates the pheromone from the water flowing over it. The partially buried larvae give off tiny amounts of a pheromone called petromyzonol sulphate while they’re feeding. This is one of many chemicals that guide adult fish as they swim upstream, signalling places with good habitats for breeding and for juvenile fish to grow.
The samplers are then collected, put on ice and sent back to the lab where Dr Baker extracts out the pheromone and determines the amount present. So far, two sampling events have been conducted in 2023 and 2024, with both successfully picking up lamprey pheromones, confirming their presence in the catchment.
“We can detect the chemical in the femtomolar range, which is a concentration of around 5g (one teaspoon) in 580,000 Olympic-sized swimming pools!” - Dr Cindy Baker
Anna Henderson is a DOC freshwater ranger and has been lucky enough to see lamprey a few times in her career.
“They’re really different from our other native fish. Like whitebait, lamprey migrate up and down streams, and spend some of their lives at sea. While at sea they are parasitic – they suck onto fish, sharks and whales and use their blood and body fluids for food.”
Key findings and next steps
The presence of lamprey in the Te Hoiere catchment is a positive indicator for the ongoing health of the waterway, though much remains to be learned about their distribution and population dynamics. The next steps include expanding the sampling efforts to cover more areas within the catchment and conducting more detailed habitat assessments to identify potential breeding sites.
“Understanding the key areas lamprey are using within the Te Hoiere catchment is important for protecting the population. Using both pheromone sampling and targeted fishing will allow us to determine densities of larval lamprey and monitor temporal trends in the population. This is important for assessing the effectiveness of restoration efforts.” - Dr Cindy Baker.
Community and iwi involvement
Community involvement is a crucial aspect of the project. Ngāti Kuia and other local iwi have been engaged from the outset, sharing their knowledge and guiding the project’s priorities. This joint effort to detect and protect kanakana in Te Hoiere is just the beginning. With the confirmation of their presence, further actions will be taken to ensure these ancient species continue to thrive. The combined efforts of DOC, iwi, and scientists like Cindy Baker demonstrate the importance of using both traditional knowledge and scientific innovation to safeguard our freshwater taonga species for future generations.
Additional resources:
Kanakana (lamprey) lifecycle
