The Country
  • The Country home
  • Latest news
  • Audio & podcasts
  • Opinion
  • Dairy farming
  • Sheep & beef farming
  • Rural business
  • Rural technology
  • Rural life
  • Listen on iHeart radio

Subscriptions

  • Herald Premium
  • Viva Premium
  • The Listener
  • BusinessDesk

Sections

  • Latest news
  • Coast & Country News
  • Opinion
  • Dairy farming
  • Sheep & beef farming
  • Horticulture
  • Animal health
  • Rural business
  • Rural technology
  • Rural life

Media

  • Podcasts
  • Video

Weather

  • Kaitaia
  • Whāngarei
  • Dargaville
  • Auckland
  • Thames
  • Tauranga
  • Hamilton
  • Whakatāne
  • Rotorua
  • Tokoroa
  • Te Kuiti
  • Taumurunui
  • Taupō
  • Gisborne
  • New Plymouth
  • Napier
  • Hastings
  • Dannevirke
  • Whanganui
  • Palmerston North
  • Levin
  • Paraparaumu
  • Masterton
  • Wellington
  • Motueka
  • Nelson
  • Blenheim
  • Westport
  • Reefton
  • Kaikōura
  • Greymouth
  • Hokitika
  • Christchurch
  • Ashburton
  • Timaru
  • Wānaka
  • Oamaru
  • Queenstown
  • Dunedin
  • Gore
  • Invercargill

NZME Network

  • Advertise with NZME
  • OneRoof
  • Driven Car Guide
  • BusinessDesk
  • Newstalk ZB
  • Sunlive
  • ZM
  • The Hits
  • Coast
  • Radio Hauraki
  • The Alternative Commentary Collective
  • Gold
  • Flava
  • iHeart Radio
  • Hokonui
  • Radio Wanaka
  • iHeartCountry New Zealand
  • Restaurant Hub
  • NZME Events

SubscribeSign In
Advertisement
Advertise with NZME.
Home / The Country

Year in Review: Lake Rotoiti catfish cull

Samantha Olley
By Samantha Olley
The Country·
11 Jan, 2019 06:00 PM4 mins to read

Subscribe to listen

Access to Herald Premium articles require a Premium subscription. Subscribe now to listen.
Already a subscriber?  Sign in here

Listening to articles is free for open-access content—explore other articles or learn more about text-to-speech.
‌
Save

    Share this article

Bay of Plenty Regional Council biosecurity team leader Shane Grayling is leading the fight against catfish in Lake Rotoiti.

Year in Review: "The population just went boom." This story about an explosion in Lake Rotoiti's catfish numbers was one of The Country's most popular reads of 2018.

"Business as usual won't suffice."

That's the message from Bay of Plenty Regional Council's biosecurity team leader Shane Grayling, leading the fight against catfish in Lake Rotoiti, the only known incursion in the region.

Nearly 35,000 were caught in the lake in the year to June, more than 10 times the number the year before.

Seven-thousand were caught in one night in Te Weta Bay.

Advertisement
Advertise with NZME.
Advertisement
Advertise with NZME.

Grayling told the Rotorua Daily Post the shallow, weedy, sheltered bay was the "perfect habitat" for catfish.

Bay of Plenty Regional Council biosecurity team leader Shane Grayling is leading the fight against catfish in Lake Rotoiti. Photo / Stephen Parker
Bay of Plenty Regional Council biosecurity team leader Shane Grayling is leading the fight against catfish in Lake Rotoiti. Photo / Stephen Parker

"They feed on just about anything, they are very good breeders, they predate and outcompete other species and they are considered the single biggest threat to kōura.

"We are assuming what the impacts are going to be but the only way you're really going to know is the worst-case scenario if they establish, and we don't want to leave that to chance. There is also the possibility that they impact on water quality by suspending sediment."

Advertisement
Advertise with NZME.

Grayling said the regional council had only found the fish in "a few isolated places" until earlier this year.

"Then something happened and the population just went boom."

He said abnormally warm lake temperatures last summer may have been the cause.

A mature catfish. Photo / File
A mature catfish. Photo / File

Many of the netted specimens are put in freezers and sent to the University of Waikato where their stomach contents are examined.

When asked what the chances are of the fish reaching other Rotorua lakes, Grayling said it was "definitely a possibility".

"We are going to be doing quite a lot of work in Lake Rotorua and the Kaituna River to see if they have spread into there because at this stage there is no barrier stopping them."

He said people posed the biggest risk of spreading the pest species.

"People need to be fairly careful if they are moving from one water body to the next and check their gear."

Grayling said catfish were "hardy creatures", that could live up to 48 hours out of the water, and were known to hide away in boat trailers.

He said $300,000 a year was budgeted for the catfish response.

Advertisement
Advertise with NZME.

A community catfish co-ordinator and a new biosecurity officer are being hired.

The co-ordinator will provide training and catfish trapping gear to anyone keen to "get their hands dirty".

Meanwhile, more than $90,000 worth of research strategies are being carried out by NIWA and the University of Waikato, covering water-quality effects, catfish behaviour, surveillance and ways of controlling the population.

Grayling said "aquatic pests are always very tricky to control" and individuals need to be responsible.

"One small mistake by them can cause a huge problem for everybody else."

Te Arawa Lakes Trust chief executive Karen Vercoe said "we know from recent monitoring that kōura are doing well in Rotorua so keeping them [catfish] out of Rotorua and our other lakes is important".

Advertisement
Advertise with NZME.

Rotorua Lakes Community Board chairman Phill Thomass said the Rotoiti community had been "extremely concerned" since the discovery of catfish, "but the explosion in their numbers, and finding them around many parts of the lake this year has shocked and galvanised everyone into action".

He said there were "no easy fixes".

"The saddest comment I've heard is: 'It's too late to do anything. The horse has bolted.' I can't accept that, and neither can our lakes."

Brown bullhead catfish
• Introduced to New Zealand in 1877
• Throughout the Waikato River system
• Typically grow 23cm to 30cm in length
• Can lay thousands of eggs

Save

    Share this article

Latest from The Country

The Country

Women make their mark at sheep dog trials

07 Jul 11:12 PM
The Country

Red meat exports hit $1.15b in May despite drop in volumes

07 Jul 11:02 PM
The Country

$3.2m confirmed for rural health centre

07 Jul 09:14 PM

From early mornings to easy living

sponsored
Advertisement
Advertise with NZME.

Latest from The Country

Women make their mark at sheep dog trials

Women make their mark at sheep dog trials

07 Jul 11:12 PM

Nine women were among the 23 finalists at the Bayleys Sheep Dog Trials.

Red meat exports hit $1.15b in May despite drop in volumes

Red meat exports hit $1.15b in May despite drop in volumes

07 Jul 11:02 PM
$3.2m confirmed for rural health centre

$3.2m confirmed for rural health centre

07 Jul 09:14 PM
Cardrona Hotel sale could set Trade Me record: 21k views in under a week

Cardrona Hotel sale could set Trade Me record: 21k views in under a week

07 Jul 09:01 PM
Solar bat monitors uncover secrets of Auckland’s night sky
sponsored

Solar bat monitors uncover secrets of Auckland’s night sky

NZ Herald
  • About NZ Herald
  • Meet the journalists
  • Newsletters
  • Classifieds
  • Help & support
  • Contact us
  • House rules
  • Privacy Policy
  • Terms of use
  • Competition terms & conditions
  • Our use of AI
Subscriber Services
  • NZ Herald e-editions
  • Daily puzzles & quizzes
  • Manage your digital subscription
  • Manage your print subscription
  • Subscribe to the NZ Herald newspaper
  • Subscribe to Herald Premium
  • Gift a subscription
  • Subscriber FAQs
  • Subscription terms & conditions
  • Promotions and subscriber benefits
NZME Network
  • The New Zealand Herald
  • The Northland Age
  • The Northern Advocate
  • Waikato Herald
  • Bay of Plenty Times
  • Rotorua Daily Post
  • Hawke's Bay Today
  • Whanganui Chronicle
  • Viva
  • NZ Listener
  • Newstalk ZB
  • BusinessDesk
  • OneRoof
  • Driven Car Guide
  • iHeart Radio
  • Restaurant Hub
NZME
  • About NZME
  • NZME careers
  • Advertise with NZME
  • Digital self-service advertising
  • Book your classified ad
  • Photo sales
  • NZME Events
  • © Copyright 2025 NZME Publishing Limited
TOP