top of page

Not your usual cup of tea: Southland's tannin stained streams

Writer: Lorna DooganLorna Doogan

Written and photographed by Lorna Doogan, National Coordinator

Finding macro invertebrates in the Pourakino Awa - Southland
Finding macro invertebrates in the Pourakino Awa - Southland

In February 2025, Mountains to Sea Conservation Trust dipped our toes into southern waters. The wānanga with Thriving Southland covered National Īnanga Spawning Programme, community-based freshwater monitoring, and how to run community spotlighting events.


“It was really helpful to understand the narrow strip of whitebait spawning habitat and practical information about how to find them. Really interesting and useful information for us to take forward. Plus all the nifty examples of facilitation skills for great events” - Keith Finlayson, Senior Land Sustainability Officer, Environment Southland

Learning about the National Īnanga Spawning Programme | NĪSP from Nic Naysmith
Learning about the National Īnanga Spawning Programme | NĪSP from Nic Naysmith

Over the two day wānanga, we travelled from the mudflats and saltmarsh of the Aparima - Riverton estuary up to the headwaters of the Pourakino Stream. Winding past the whitebaiting huts at the salt water wedge up to where the Pourakino travels to the north through willow lined banks, past remnant beech forests into the tannin stained water of the upper tributaries. As the fallen leaves and sticks "steep" in the awa, the volatile tannins leach out into the water leaving it anywhere from a red to a black hue. A bit like a cup of tea!



Nic Naysmith used a salinity meter to find the 'saltwater wedge', searching for likely īnanga spawning grounds. The 'saltwater wedge' describes how more dense salt water pushes underneath the freshwater layer on an incoming tide. At the very top of this wedge on the highest tide is where the adult whitebait will spawn, so their eggs can develop out of the water away from predators. The eggs hatch out at the next big tide, and the tiny īnanga head out to sea to fatten up before they run back up stream as juveniles.

"This was an amazing opportunity to meet another group of people passionate about īnanga conservation. If we can find this kind of support all around the motu we may just save this species from further decline." - Nicholas Naysmith, National Coordinator of NĪSP


In an oxbow that was a test site for willow removal we found adult īnanga. After doing habitat assessments it looked like positive space for future spawning events. Īnanga (adult whitebait) are super picky about where they want to spawn. The bank angle, salinity and type of vegetation determine whether the adults are able to access the moist dark root mats at the top of a tide to lay their eggs. Too steep, too shaded by large trees or too many predators eating eggs will result in an unsuccessful spawning and reduced run of juvenile whitebait. Find out more about īnanga here.


"The knowledge shared and connections made during these two days have set us up for exciting work ahead. A highlight for me was actually meeting the Mountains to Sea team and picking your brains on all the cool community events you run. Such a great way to engage people and get them involved in looking after their special part of the world." - Sarah Thorne, Thriving Southland


Turns out in Southland, the sun sets a lot later than in the winterless north. Warm jumpers and waders were donned to search for the nocturnal critters that come out to play. The hīnaki (fish traps) were set and head torches turned on in the fading light. Rachel Halder from Thriving Southland led our group up a track to a stoney bank of the Pourakino. Upland and common bullies darted away from the torch light and long fin eels retreated back under banks. The adult mayflies and damsel flies flocked to the spotlights creating thick clouds.


Ainsley Adams in the Pourakino Awa - taken by Lorna Doogan
Ainsley Adams in the Pourakino Awa - taken by Lorna Doogan
"What a great opportunity we had to learn all about the fantastic mahi Mountains to Sea Conservation Trust are doing across our country. Learning so many new things from Pat, Lorna and Nic was definitely a highlight as well as seeing what neat creatures are living in our local Southland awa! Their enthusiasm and passion really comes through in their work and teaching!" - Ainsley Adams


What next?



Help Mountains to Sea Conservation Trust to protect te taiao - we appreciate every donation and volunteer sign up.


Funders

Mountains to Sea Conservation Trust provided this wānanga due to generous funding from Ministry for the Environment through Wai Connection.


Our partner in Southland

Thriving Southland is our partner delivering the Wai Connection Project in the Southland rohe.



Comments


bottom of page