The regional council will be checking ornamental ponds in Ōmokoroa and Maungatapu starting this month in a bid to stop the spread fo freshwater pests into local waterways.

A Bay of Plenty Regional Council authorised contractor will visit Maungatapu and Ōmokoroa properties to check outdoor ponds from October 2018 to June 2019.

Bay of Plenty Regional Council biosecurity officer Donna Watchman said the council is searching for invasive weeds and pond fish such as koi carp and rudd that can eat and out-compete native fish.

"In the wild, koi and rudd can make water murky and unhealthy when they stir up sediments and reduce oxygen levels," Watchman said.


"Invasive weeds like salvinia and water hyacinth grow as thick floating mats and can choke waterways, clog irrigation intakes and aggravate flooding."

Watchman said the regional council found at least one pest plant in 27 per cent of the 303 ponds checked in the Katikati, Ōropi, Ōhauiti, and Welcome Bay areas in 2016. Fortunately, no pest fish were found.

"Pests that seem safely contained in a pond can easily be spread elsewhere by birds, pond overflows, earthworks machinery, or if they're shared with neighbours and friends," she said.

"People often have no idea that they have pests in their ponds. By casting an expert eye over them we can help people understand what to look for and minimise the risk of liberation into natural waterways."

A new property owner, who knew what to look for, was a huge asset in helping find and remove koi carp from the Katikati area last year, Watchman said.

The regional council contractor, who will be carrying identification, will leave a notice about the visit in the letterbox.

Or the notice will be posted out after the visit to each property and occupiers will be advised if pests are found or further action is needed.

To discuss the pond checks or find out more about pond pests, people can chat to the contractor when they visit, or contact a regional council biosecurity officer on 0800 STOP PESTS (0800 786 773) or email


Information about aquatic pests is also available at