Cedenco New Zealand managing director Tim Chrisp said the acquisition was completed with the formation of Cedenco Aquaculture, a sister company to Cedenco Foods NZ, both under the ownership of the Imanaka Group, Japan.
Cedenco makes primary ingredients such as pastes, purees and frozen vegetables for other manufacturers in New Zealand and internationally.
"We see long-term value in the aquaculture sector," said Mr Chrisp. "Cedenco has experience and expertise in exporting primary food products, particularly to Asia. We see it as an opportunity to broaden our footprint in New Zealand's primary products business."
NIML processes mussels harvested in the Coromandel, with some 1.8 million mussels going through its factory in a 24-hour cycle. The Greerton premises include the world's first plant using robotic opening systems.
Mr Wells said the plant had set a record by processing 110.8 tonnes in a 24-hour period, and was now aiming to exceed 115 tonnes.
Factory manager Amelia Austin said the company had increased throughput of the half-shell mussels that are its primary export product from 4.8 tonnes to 6.2 tonnes an hour.
"Because our machines are robotic, any adhesions to the mussels really affect our throughput," said Ms Austin, who joined NIML last December after returning from spending seven years with wet fish company New England Fisheries in the UK.
"We've been improving the way our inspections are done at the mussel farm to make sure the product is suitable for half-shell processing."
NIML had also made changes to the way the product was handled in the factory.
"To get that throughput improvement required a lot of planning, communicating and getting the right people in the right spots with the right motivation," she said.
As well as exporting half-shell mussels, NIML also produces more than 50 per cent of the country's domestically eaten marinated mussels under a number of brands. The company recently installed new equipment to produce its own marinade vinegar base, previously mixed in Nelson.
The plant has now extended its marinade production having been awarded house brands to add to its complement of premium branded products such as Sealord's recently launched new range of flavours.