A whistleblower from the State's sea fisheries regulator made a protected disclosure over its levels of regulation to the Minister for Agriculture, Food and the Marine and members of an Oireachtas committee.
The whistleblower, an officer with the Sea Fisheries Protection Authority (SFPA), was advised to submit a protected disclosure to the minister, Michael Creed, and to members of the Oireachtas committee on agriculture, food and the marine last year after he was informed data breaches were being investigated.
The officer said he had alerted an international sustainable fishing certifying body about under-recording of catches of herring when his initial reports to his employer were not acted on, he says.
The official first became concerned in 2012, when the prestigious Marine Stewardship Council (MSC) awarded a sustainable accreditation to the Celtic Sea herring fishery.
The official believed the MSC was not aware of under-recording in the region of 50pc of catch returns in four Irish fishery harbours.
He estimated almost 8,000 tonnes of fish was being landed illegally, and that this had environmental consequences as subsequent Marine Institute stock assessments were relying on "false data".
In his protected disclosure, the official explained the under-recording involved "fraudulently trying to declare large volumes of fish caught over the vessels' quota as cooling water/RSW (refrigerated sea water)" during bulk transport from port to processors.
The official says he notified his superior on October 31, 2012, but alleges no enforcement action was taken by the SFPA at that time, and he then contacted the MSC. In his disclosure to Mr Creed, he says he was then told a formal investigation had been initiated by the SFPA with the gardai into his actions for alleged breach of the Data Protection Act and Sea Fisheries and Maritime Jurisdiction Act.
He told Mr Creed this was "immensely damaging and stressful personally and on family members who are fearful I'll be sacked for revealing the truth to the MSC auditors". The official subsequently made his own statements to gardai.
The Celtic Sea herring fishery lost its MSC sustainability certification early in 2018.
The seasonal herring fishery was closed last month only days after it opened when under-sized fish were landed.
Separately, the European Commission has already ordered Mr Creed's department to conduct an administrative inquiry into its ability to apply EU fishing rules. The Commission said the inquiry must evaluate Ireland's "capacity to apply the rules" which govern the management of fish catches within EU waters, and said its request arose from "the severe and significant weaknesses" detected in the Irish control system during an audit carried out in March 2018 at Killybegs, Co Donegal.
A spokesman for Mr Creed told the Sunday Independent: "The protected disclosure referred to deals with operational fisheries control matters, responsibility for which rests with the SFPA.
"The minister has been copied with the relevant documents and he is aware of the issues and the concerns.
"As the matter is legally within the remit of the SFPA, it has undertaken actions in relation to the issues raised and has advised the minister of same. The minister has asked the SFPA to keep him informed of any further developments."
The SFPA refers to one protected disclosure in 2018 on its website and states "the issues are being assessed and investigated as appropriate".