In a country first, a ban is about to be placed on winter-fishing in parts of Canterbury due to declining river quality.
Fish & Game said they put the ban in place in order to preserve the fisheries in the region.
There was a serious lack of water management policies and more needed to be done to save lowland streams and rivers for future generations, the organisation said.
The ban comes into force on Saturday night, and means no fish can be taken east of State Highway 1 from Rakaia River in the south to Waiau River in the north.
It has been officially approved by the head of the Department of Conservation.
North Canterbury Fish & Game Council chair Trevor Isitt said the region's waterways had suffered years of environmental degradation due to intensive agriculture, and a lack of water monitoring.
"All of our lowland streams now have a classification from mildly to heavily polluted, which is affecting the aquatic environment that our fish live in, and [it] is affecting the spawning that needs to go on for the recruitment of fish in the future.
"There's been a huge decrease in fish numbers over the past few years; last season, the sea-run nearly collapsed."
Canterbury's regional council, Environment Canterbury (ECan), needed to focus on regulating and enforcing water consents, Mr Isitt said.
The only way to make a change to the state of the water was to return to a fully democratically elected council, he said.
"We want to get the message across - we're in the business of providing fishing opportunities, not taking them away - so it's really reluctantly that we've gone down the path of putting a ban in place."
'What else can we do?'
Peter Robinson has fished at the Waimakariri River his whole life. Intensive irrigation on the plains had played a huge role in the the degrading health of the region's waterways, he said.
"The river doesn't behave like it used to, it runs a lot lower, it's warmer, and we get a lot of weed growth in it as well - so it's not very good for the fish.
"The salmon season has been really hard. I've talked to a lot of people fishing down here, and they're just happy to get a fish," Mr Robinson said.
It was sad a ban was needed, he said.
"What else can we do? Do we just stand by and do what we've always done? People can argue that it's just because of the drought but I think it's more than that, we have a systemic problem, the streams aren't healthy anymore."
ECan surface water science manager Tim Davie said it had taken decades for lowland streams to become degraded, and would take many more to remedy.
Recognising the problem was a key platform in establishing the Canterbury Water Management Strategy, which aimed to protect and improve fresh water.
"We know in the lowland streams there is a water quality problem. In the alpine feed rivers, the water quality is still very good.
"The area of the ban is code red for water consents, which means no more water can be taken from the rivers for irrigation."
Rules limiting the nutrients which could be discharged from farms were in place, and ECan was working with farmers to ensure stock was kept out of waterways.
"ECan works with all interested parties, including Fish & Game, on finding solutions so that agriculture can prosper without degrading our waterways."
The ban will run for the entire winter fishing season through until the end of September.
If anyone is caught fishing while the ban is in place they can be prosecuted, or have equipment confiscated.
Lake's toxic bloom kills pets
Meanwhile, a lake on Banks Peninsula is so toxic this year it has killed sheep and household pets.
Lake Forsyth has green sludge on its shores, and ECan has put up signs warning locals and tourists to stay away from the water.
Mr Davie said there were records of rowing regatta being cancelled in the 1800s due to the algae bloom, so it was nothing new.
He said the health of the lake had been improving over the last six years, but this year the bloom was the worst it had been in a long time and had caused the death of sheep, cats and dogs.
Mr Davie said sediment from the slopes around the lake had high natural levels of phosphorus, which caused the bloom to occur.