Halting the spread of pest fish

In the past few years, we’ve seen an increase in the occurrence of some introduced fish species in Bay of Plenty waterways, including the Pāpāmoa storm water system recently.
The introduction of exotic fish in New Zealand waterways is an increasing problem that causes substantial harm to our freshwater habitats.

In 2017, four adult perch were found in the Pāpāmoa storm water system, prompting further surveys by the Tauranga City Council, with support from the Bay of Plenty Regional Council and Biosecurity New Zealand. Fifteen kilometers of our storm water system has since been surveyed, and fortunately, no juvenile perch were found.

In April 2018, an adult male Suckermouth Catfish was found in the Emerald Shores area of the storm water system. After sending it to Te Papa for identification, it provided proof that these fish are able to survive in the New Zealand climate. A further delimiting survey was carried out, using nets, traps and electric fishing to look for a breeding population. Given no further Suckermouth Catfish have been found, it is thought that this one may have escaped from an aquarium or been released into the waterway by its owner.

Peter Mora, Stormwater & Wastewater Drainage Engineer at Tauranga City Council says it’s important to remember that it’s illegal to release (pet) fish or move fish between waterways and to report pest fish to the council if you see any.

“The spread of these fish threatens our freshwater environments, native species and biodiversity. It’s fundamental that people stop moving fish, whether by accident or on purpose.

These species have the potential to survive and breed, particularly if both male and female fish are released into the waterways. They can move to other waterways via flooding too.”

The storm water systems are monitored by the Tauranga City Council, who run a regularly quarterly surveillance and respond to any public reports.