Inspectors found major irregularities in most of Malta’s tuna farms during routine checks last year but the operations were allowed to continue, according to The Sunday Times of Malta.

Sources in the Fisheries Department said that inspections on the island’s tuna pens between September and October of 2018 uncovered how ranchers had concealed hundreds of extra fish, amounting to at least €4 million ($4.5 million) in illegal catches.

Some pens also had missing fish – believed to have been sold on the black market – while others had included tuna that was not at the right age, with inspectors suspecting the extent of the alleged irregularities could have stretched into several millions of euros more.