Student scientists monitoring lagoon

Dozens of budding young scientists descended on Tomahawk Lagoon for a training day with Ecotago scientists on Friday, as the ongoing monitoring of the lagoon’s health gets under way for the year.

Ecotago scientists Andrew Innes, Murray Vickers, Jonathan Kim and Robert Smith, and Birds New Zealand scientist Mary Thompson, spent the morning working with pupils from Tahuna Intermediate School, Otago Girls’ High School and Queen’s High School, teaching them techniques for monitoring the water and biodiversity of the lagoon.

Mr Innes said the aim of the training day was to "teach the kids the basics of field work and lab analysis, so they can take a more active role in monitoring the lagoon".

The lagoon project was shifting its focus this year to encourage young scientists to work towards a better understanding of the science and making a difference for Tomahawk Lagoon and catchment.

The pupils would develop their skills in monitoring techniques for investigating water quality and biodiversity at different sites around Tomahawk Lagoon and the catchment of the upper lagoon creek.

"Later in the year, we would like the pupils to have the confidence to start carrying out their own investigations," Mr Innes said.

Alongside Tahuna, Otago Girls’ and Queen’s, the Tomahawk Lagoon schools project intended to also include Bayfield High School and King’s High School pupils this year.

In late winter, the Ecotago-led project and the local residents’ Tomahawk Lagoon Catchment Group would hopefully work together on some restoration work in the upper catchment.

"After that, we will be monitoring the results from that to see whether that restoration work has improved the health of the creek and lagoon."

Mr Innes said it was good to see so many young people interested in the lagoon and keen to be involved in monitoring its health and biodiversity.

"They have all had a chance to try their hands at different techniques, so it will be good for them to get stuck into the work in the coming months," he said.

Tahuna Intermediate School teacher Karen Parker, who was at the lagoon on Friday with 27 year 7 and 8 pupils, was pleased to see so much enthusiasm for the project among the children.

"They are really enjoying the experience of being out here at the lagoon, and learning the monitoring techniques," Ms Parker said.

Tahuna Intermediate watched over the site closest to the Ocean Grove Domain Hall and had observed with interest as populations of birds and fish waxed and waned in recent years.

On hand with a telescope to help the pupils identify the resident birds at Tomahawk Lagoon, Birds NZ representative Mary Thompson said there had been interesting patterns among bird species over the years.

The numbers of black swans had fluctuated enormously, as well as other species with a presence at the lagoon including the NZ scaup (black diving duck), Australian coot, marsh crake and red-billed gulls.

The Ecotago Charitable Trust started monitoring water quality at Tomahawk Lagoon, in conjunction with Dunedin schools, in 2016 and by the end of 2022 had a robust data set that suggested that the environmental health of the lagoon was poor.

The Otago Regional Council (ORC) completed a detailed catchment management plan in 2023, which recommended that restorative action, including riparian (water-side) planting, be undertaken soon.

The Tomahawk Lagoon Catchment Group was also formed to take an active role in efforts to care for the lagoon.

ORC has allocated $260,000 over three years "to enhance the Tomahawk Lagoon catchment through community action to contribute to a healthy ecosystem for all to enjoy".

brenda.harwood@thestar.co.nz