Eels die in poisoned stream
A contaminant caused the death of thousands of tuna in a Southland waterway, evidence suggests.
More than 2600 eels were found dead in the Low Burn Stream and smaller nearby streams just off the Mataura River in February.
It sparked an Environment Southland investigation into the cause of the mass casualty of the taonga, which uncovered a poison in the waterway.
Donna Ferguson, the resource management manager for the regional council, said while she could not go into the details as it was still an active investigation, it appeared the eels did not die of natural causes.
“Evidence suggests the deaths have been caused by the acute impact of a contaminant in the waterway, rather than disease,” she said.
Investigators were continuing to collect evidence from people to establish the source of the contaminant, which also killed a limited number of other species in the water.
“The stream has been severely impacted and is now in poor health from an ecological perspective.
“We cannot confirm that the waterway is clear of the contaminant that likely caused this event as remnants may still be present and take some time to work their way through the system.”
Ferguson said there were fewer than 20 other species found by people from Hokonui Rūnanga, Te Ao Mārama and Environment Southland who recovered the dead tuna. It would take some time for biological communities to repopulate the stream.
“We are speaking with experts to understand the longer-term impact on the waterway and how long the ecosystem might take to recover.”
Riki Parata, the kaiārahi taiao of Hokonui Rūnanga, said he would wait to comment on the contaminant until more evidence was presented.
He said the tuna had been disposed of to prevent disease and further impacts on the environment.
“They did take some for tissue sampling, but because they were unclear on what the contamination was it was treated as a biohazard risk. So it had to go to AB Lime, the landfill.“
Ferguson would not discuss where investigators were focusing their inquiries about the origin of the contaminant.
However, there were farms, private property and businesses upstream of the site where the tuna were discovered.