The Waikato-Tainui tribal body wants to tighten the rules on the commercial fishing of eels, or tuna, in the region.
It has released for consultation a series of bylaws developed with the Ministry for Primary Industries (MPI) under their arrangment for co-management of the Waikato River.
The proposals include increasing the minimum size of commercially harvested tuna from 220 grams to 300, and to reduce the maximum size from 4 kg to 2kg.
The fisheries advisor for the body, Nicholas Manukau, says that will allow the larger tuna to spawn.
He says the Waikato River Catchment is the largest eel fishery in the country, and has been intensively fished since the 1970s.
Mr Manukau says there has been a decrease in the abundance of eels in the river, and new bylaws would benefit all users of the river and future generations.
Public consultation runs from 11 September to 23 October.
The full list of the proposed bylaws:
Proposed Bylaw 1 - Incidental catch and release of oversized eels below migration barriers
Proposed Bylaw 2 - (Temporary Rahui) Temporary prohibition on fishing in an area due to drowning
Proposed Bylaw 3 - (Permanent Rahui) Permanent prohibition of fishing in a part of the Matahuru stream, Lake Waikare, to protect a waahi tapu site (shallow lake and polluted)
Proposed Bylaw 4 - (Seasonal Rahui) Seasonal closure prohibiting the commercial harvesting of eels from the Lake Waikare and Whangamarino tributaries during the tuna heke - March to June
Proposed Bylaw 5 - Increasing the minimum size of both species of commercially harvested eels from 220 grams to 300 grams
Proposed Bylaw 6 - Reducing the maximum size for commercially harvested shortfin eels from 4kg to 2kg
Proposed Bylaw 7 - Reducing the maximum size for commercially harvested longfin eels from 4kg to 2kg