Fisheries NZ released the proposals yesterday as part of its twice-yearly review of catch limits for key recreational and commercial fishing species.
Fish Mainland advocates for the interests of recreational anglers, and director Alan Key, of Gore, said limits for key species in Otago and Southland waters, such as blue cod, had been reduced by about half over several years, as a result of successive reviews.
The latest proposals include reducing recreational daily catch limits for blue cod from 15 to 10.
Reductions to commercial limits would be between 20% and 25% and, if approved, come into effect from October.
However, Mr Key said the reductions were not justified by actual stocks, and government data used to set limits and determine fisheries management was out of date, and therefore flawed.
"The big problem is [Fisheries NZ] hasn’t got sound data on which to base their actions. If a decision is not based on data, it’s based on opinion, and you run the risk of inadvertently making things worse."
He acknowledged there had been a "lull" in blue cod stocks reported by anglers, but that had since turned around.
"Our reading of that was that increasing water temperature was a contributing issue, but that is now dropping again and, according to reports from people out there fishing regularly, stocks are increasing again."
He said a possible alternative to reducing catch numbers was increasing minimum fish length.
"Increasing the legal length limit, say from 33cm to 35cm, has a significant effect on the yield of edible meat. So you can catch fewer fish of slightly greater size, and come away with a similar overall yield ... I’d try that for a couple of years, re-examine the data and adjust accordingly."
He said taking larger fish could also provide data about effects on spawning, potentially leading to seasonal adjustments in limits and better stock management.
The Fisheries NZ consultation includes catch limits and other management changes for nearly 30 fisheries across the country.
A spokeswoman said the proposed blue cod cuts were in response to the "latest abundance estimates".
Submissions close on July 23.
