Some whitebaiters are concerned fishing spots could be crowded as a shortened fishing season comes into effect this year.
Previously the whitebaiting season that applies to Whanganui ran from August 15 to November 30 but this year it will be shortened to September 1 to October 30.
That changes the season from 15 weeks down to just short of nine weeks.
It is the only change to whitebaiting rules this year following new legislation that started coming into force in 2021.
Last year new rules restricted diverting whitebait using only screens, no set nets closer than 20m between each other or any other diversion such as a floodgate or groyne.
Screens can only be three metres long unless fishing from a stand.
DoC's whitebait fishery manager Nick Moody said the shorter season would help reduce fishing pressure on all whitebait.
But there are concerns among whitebaiters in Whanganui the shortened season could lead to more intensive fishing and crowded spots.
"Especially the likes of the Kai Iwi stream, the smaller tributaries and things like that," Whanganui veteran whitebaiter Barry Hawthorn said.
"I wouldn't want to be fishing at the Kai Iwi stream with everybody down there in a short amount of time."
He said the shortened season and the rule whitebaiters with set nets had to be at least 20m apart could prove difficult to implement.
"I can't see how that's going to work, it isn't going to happen."
One example Hawthorn gave was where parents and children were fishing together.
He said parents would want their kids to be closer than 20m away.
The 20m restriction doesn't apply to people using a scoop or drag net.
Hawthorn had visited the DoC office in Whanganui to get the new rules printed out and was sharing them with fellow whitebaiters.
But he said it seemed like many whitebaiters here did not have a good idea of the shortened season as well as some of the other rule changes.
"I'm a bit disappointed in the way Doc has gone about informing people."
He said DoC should have been more proactive in putting out brochures and advertising the new rules.
"Most of the families who want to go out and fish on the weekend wouldn't have a clue of what's happened."
DoC's operations manager Jim Campbell said most whitebaiters had known changes would be coming and the department had been carrying out nationwide consultation discussing ways to make the fishing more sustainable.
"We've also phased the changes over three years, beginning last year, so that whitebaiters have time to adjust.
"Last year's feedback (from whitebaiters) suggests that there wasn't anything really controversial from the public, in fact, all those spoken to generally agreed with the changes."
Campbell said DoC staff would be out and about this season to check that everyone is complying with the new rules.
In terms of fishing spots getting more crowded because of the shortened season, Campbell said people needed to keep in mind the rules and etiquette around whitebait fishing.
"This means observing distances between fishers and ensuring that no more than a quarter of the stream is blocked off by anyone's net."
Senior freshwater ecologist Stella McQueen, who's from Whanganui but is now based in Christchurch, said the 2021 rule changes around whitebaiting were long overdue.
Historically whitebaiting rules had not been changed since the 1990s and before then had been "piecemeal" and mostly set up to stop whitebaiters "killing each other over favourite places", she said.
"What it's turned into is this almighty fishery where people can catch hundreds of kilograms in a good day and sell it for over $100 a kg."
She said some people would take several months off work in the hope of "making it big" in whitebait and older regulations could not deal with the commercial drive behind some of the fishing.
Whitebait are the juveniles of six species of fish and five of them are known as migratory galaxiids: inanga, banded kōkopu, giant kōkopu, kōaro and shortjaw kōkopu.
Of those the inanga, giant kōkopu and kōaro are in DoC's at-risk category, while the shortjaw kōkopu is in the threatened category.
The shortjaw kōkopu is described as facing a "high risk of extinction in the medium term".
DoC said the three at-risk species could become threatened if conservation management reduces, a new threat arises or their population declines continue unabated.
McQueen said legislators should have taken the financial incentive away from whitebaiting and made it illegal to be sold.
She said whitebaiting should be something you do to "catch a feed for your family" but not to take time off work to try to hit the jackpot with a threatened or at-risk, native species.
As for the shortened season leading to more intensive fishing, McQueen said she was not too worried as the baby fish were usually swimming back in from the sea for a period of three to four months.
"They hatch in freshwater, tiny babies go out to sea on floods ... spend a couple of months out at sea and then swim back in and that's the time they're in danger from whitebaiters.
"Compressing down whitebait fishing season is targeting a smaller amount of that whitebait coming back into land season."