16 November, 2023

Eels killed in local stream: toxic pollutant suspected

More than 20 eels were found dead in a stream at Philomel Reserve, Bayswater, last weekend, in a suspected case of toxic contamination.

The deaths are a massive blow for environmentalists who have worked hard to restore areas around the reserve.

It is feared the loss of so many large eels could set back the local ecosystem by decades. The cause of the deaths was still unclear this week, with water testing by Auckland Council’s Healthy Waters continuing as the Flagstaff went to press.

But the department’s head of sustainable outcomes, Tom Mansell, suspected chemicals tipped into a gutter were to blame.

Initial testing showed normal pH and ammonia levels, but eels were durable creatures so it would take “something pretty toxic” to do so much damage, Bayswater resident Mansell said.

The catchment area for the stream was mostly impervious, so toxic pollutants went directly into the stream via drains.

He believed the eel population could take decades to fully recover as some in the stream were up to 40 years old.

The Restoring Takarunga Hauraki (RTH) environmental group has been doing restoration work in the reserve for the past two years, weeding out pest species and planting natives to shade the stream.

RTH community coordinator Lance Cablk told the Flagstaff the loss of the eels was “just awful”, especially considering the amount of time spent restoring the area.

The group’s kaupapa and tikanga Māori coordinator, Zane Catterall, who has led the restoration project, said it was “heartwrenching” in a place where the eels had been coming back in larger numbers over the last decade.

Mansell urged residents to dispose of chemicals responsibly and to embrace practices such as washing cars on a lawn to avoid direct runoff into waterways.