"Nine police officers supported today's inquiries. Police were spread across five individual properties."
About 80 officers searched eight homes in the Māhia, Wairoa, Whakātane and Kawerau areas, beginning in the early hours of this morning.
At some of these properties they were supported by New Zealand Police, although no arrests were made.
The development marked the next phase of a six-month-long investigation into an alleged black market crayfish ring.
"We believe this was a highly organised black market ring which took in excess of 4300 crayfish with a commercial value of over $300,000 from the Māhia area in Hawke's Bay over a seven-month period," said Orr.
"The crayfish numbers identified – more than 4300, relate to historic sales allegedly conducted over a seven-month period. No crayfish was seized by MPI Fishery Officers on Wednesday."
MPI believed the crayfish was then sold on the black market in the Auckland, Kawerau, Rotorua, Tūrangi, Gisborne, Napier and Blenheim areas.
"The investigation to date has focused on gathering evidence, including surveillance of alleged offending," he said.
"Today's (Wednesday) search warrants will provide further information to support the investigation. We will be gathering a number of formal statements from suspects as part of this work."
Orr said MPI fishery officers worked hard to protect fishing resources from people who sought to profit illegally.
"We hope today's development sends a strong message to others tempted by greed – that we will do everything within our powers under the Fisheries Act to protect the fishing resources owned by all New Zealanders."
Illegally harvested seafood can become evidence for any subsequent proceedings such as court cases.
"Of course the court does not appreciate us showing up with a bag of wet, smelly, mouldy two-month-old pāua, so the next best thing for our officers to do is to lay out any kaimoana as quickly as possible, take photos to show the court, then put everything back in the ocean if it has a high chance of surviving," national manager fisheries compliance at MPI Steve Ham said.
"Usually shellfish and rock lobster will recover if the time out of the water is kept to a minimum.
"If the kaimoana is dead or damaged, we can't just throw it back in, as it could wash up on the shoreline, so we will take it back to our offices where it is measured, weighed, tagged, and photographed.
"It's then frozen and kept till the court case is over."
Ham said there were freezers at fisheries offices around the country, so every so often MPI would take the confiscated fish and seafood and return it to the marine ecosystem.
"This enables this illegally harvested seafood to enter the food chain in a controlled manner," he said.
"This means it is well documented where the illegally harvested seafood has been released and how much was put back into the sea, and as a result we don't overwhelm the ecosystem."
MPI was unable to offer more detail on the substance of the investigation as the matter was ongoing.
MPI encourages people to report suspected illegal activity through the ministry's 0800 4 POACHER number.
MPI receives around 7500 calls a year on this number, Orr said.
"About 1000 of the calls we receive are related to suspected illegal fishing activities."