Fisheries New Zealand is being challenged over claims the commercial snapper catch can be increased without posing a risk to endangered Māui dolphins.
The snapper quota off the North Island's west coast has risen by 23 percent to 1600 tonnes a year, and the amount that can be taken for customary and recreational use has also jumped.
Marine biologist Liz Slooten said this increases the chance of Māui dolphins ending up as bycatch, and coincides with a survey showing their population has fallen 14 percent to just 54 individuals.
"It is just really surprising that new information of Māui dolphin now being down to 54, that's followed hot on the heels by this decision to increase snapper quota - it just doesn't make sense."
She said observer coverage is scarce on boats in the area, so there is no way of telling how many dolphins are ending up as bycatch.
"We simply don't have the data to say that and also there is no mention that I can see of the recent new information that Māui dolphins have declined again, there's a lot of information that's missed out of this document."
Fisheries - a division of the Ministry for Primary Industries - said it is satisfied with the protections in place for Māui dolphins.
Fisheries NZ stated in a report that was leaked that despite the decline in the number of Māui dolphins, no extra protections were needed.
It said this was because "the current fisheries measures effectively restrict the estimated level of fishing-related mortality to zero".
