"Removing fishing pressure is an important and immediate measure that can contribute to their ongoing sustainability. It is the responsible action to take," the Minister said.
The Hauraki Gulf Forum, which is pushing for a dredge-free gulf, says only a partial closure "makes no sense".
Meanwhile Phil Clow, president of the Whitianga and Coromandel Peninsula Commercial Fishermans Association, said the partial closure had impacted 22 licence holders and fishers.
He said if catches fell under three bins per hour or the meat weight fell under 10 per cent of shell weight, fishers would move on from the areas still open to dredging.
"These are not irresponsible fishers and it is overlooked that these fishers along with the 22 licence holders have now got to find other jobs or in the case of the processing factory who also holds several licences and for the fishers big decisions to be faced as to what to do with their vessels and plant."
He said fishers in the Coromandel Scallop fishery managed the fishery using a catch per unit effort (cpue) method, and a survey by NIWA showed the situation was not all bad.
"The NIWA survey carried out on scallops showed some areas had good scallop abundance while other areas had less, the survey was far from doom and gloom.
"Clearly Little Barrier and the Colville Channel have sufficient abundance to provide for utilisation.
"Like other scallop populations, Coromandel scallop abundance levels are highly variable, for example biomass was low through the early 2000s and there was plenty of fishing prior to 2000 - then peaking in 2005 before declining until 2010-11.
"These shellfish have a life cycle in the vicinity of 5-7 years. Reasons for this high mortality are from starfish, harvesting and sedimentation to name just a few threats, but threat-free, [scallops] can live twice as long."
He said the industry was open to improvements: "It's not to say future commercial harvesting may be carried out in a different way to reduce harvest mortality."
Gulf Forum co-chairwoman Pippa Coom said allowing commercial and recreational dredging to continue around the west and south of Hauturu-ō-Toi/Little Barrier, and one off the west coast of Aotea Great Barrier was very concerning.
"These are two of our most beautiful islands, with Hauturu one of the most protected places on the planet. It makes no sense for the health of the gulf, and the health of our communities, to have the seafloor around such treasured whenua being dredged."
Ngati Hei iwi kaumātua Joe Davis said he was also disappointed.
"Ngati Manuhiri have been left in a terrible position up there in Little Barrier and the Colville Straight, which has been left open for the commercial guys."
Forum co-chairwoman tangata whenua Nicola MacDonald said: "Worse still, both of the areas the minister has chosen to leave open to dredging are covered by tikanga rāhui laid down on Waitangi Day this year, and a formal s186a Fisheries Act application for a temporary closure.
"The decision diminishes the mana of the iwi, hapū, whānau, communities and all those involved in supporting the rāhui. The minister should reconsider this aspect of the decision, and/or confirm the temporary closure application."
Forum co-chairwoman Pippa Coom says more broadly, the forum welcomes the decisions by the minister to largely close the Hauraki Gulf scallop fishery.
"The scallop population in the Hauraki Gulf, Tīkapa Moana, Te Moananui-ō-Toi has collapsed. This necessary action by the minister will protect around 95 per cent of the Hauraki Gulf from damaging scallop dredging for the immediate future while a solution is found to transition the industry to hand-gathering.
"This is the beginning of the end for dredging in the gulf. The forum will continue to advocate for a completely dredge-free future."
Minister Parker says continued serious decline in scallop numbers included sedimentation, dredging and the use of GPS technology to locate and exploit scallop beds.
The two defined areas around Hauturu/Little Barrier Island and near the Colville Channel provided for a small level of utilisation, the minister says.
Co-chairwoman Nicola MacDonald declares an interest as her other pōtae as CE of Ngāti Manuhiri Settlement Trust.
