A night raid at the mouth of the south branch of the Clutha River earlier this month had resulted in positive feedback, Doc area compliance manager Bill Wheeler said.
He had been receiving irate phone calls from other whitebaiters concerned about people fishing after the 9pm cut-off and the lack of action by Doc to stop it.
Night fishing was not allowed, to give whitebait a chance to make it upstream and breed again next season.
Feedback since the raid indicated more whitebait were now making it upstream, which suggested those illegal whitebaiters had been scared off, he said.
"It's fairly positive. The message has got out that we are interested in doing something about it."
There had also been reports of night fishing in the Waitaki and at the Shag River mouth.
Doc would continue to monitor the rivers at night and would look at starting compliance action earlier in the season next year.
"Whitebait started running early this year and there were reports of people fishing before the season started."
This seemed to result in significantly more people going out whitebaiting, especially on the Taieri and Clutha Rivers, he said.
"There's been more people out on the rivers than any other year in the last five or six years."
