Otago Fish and Game council members are being asked to make big decisions on shoveler duck bag limits on "rubbish information", Terry Broad says.
Separate reports on shoveler and paradise ducks sparked debate at the council's November meeting this week.
Fish and Game officer Morgan Trotter said in a report that analysis of long-term national population trends suggested numbers to be on a slight decline, but there had been an increase since the last trend count.
Nationally, 10,168 shoveler ducks were recorded this year and in Otago 1019 were counted at 26 historically monitored sites.
Last year 951 were recorded, the lowest ever.
"Conservative regulations are the best option of ensuring sustainable harvest of the shoveler population."
In 2008, concerns about possible decline in duck numbers had led fish and game councils to reduce the daily bag limit from five to two and the season length from three months to one in most regions.
Mr Broad said it did not appear hunting had any impact on duck numbers.
"It penalises a few keen hunters.
The harvest is small, overall, and we think the population is going down, but we don't have clear evidence."
Chief executive Niall Watson said the trend was uncertain as the bird was highly mobile.
"We do need consistent rules. I'm reluctant to recommend change to the current position even though it's on the cautious side."
The council had other interest groups and organisations "looking over its shoulder" to ensure harvesting was sustainable, he said.
Monty Wright said the council had made the decision to reduce the bag limit so it needed to "hang in there" for another year or two and see what effect it had.
Council members received the report and would review the regulations next year.
They also considered the provisional game regulations for the 2010 game season, which included bag limits for paradise shelduck - 10 in area A and 15 in area B.
Mr Wright said he could not understand why there were separate bag limits for the duck.
"It's absolutely ridiculous. Figures collected by staff show the populations are about the same."
Chairman John Barlow said the council could ask staff to have another look at the numbers and report back before the council was required to make a final decision.
Regulations go to the Conservation Minister for approval.
There were no changes for the coming year.
