A Canterbury diesel mechanic has plead guilty to running a lengthy black-market paua operation.

Appearing at the Christchurch District Court Forty-five-year-old Sefton man Michael Andrew Dickson received a sentence of four months community detention and 200 hours community work when he appeared.

His offending was uncovered during a Ministry for Primary Industries investigation.

The court heard that between the periods of January to May 2015 and September 2015 to May 2016, Dickson sold 346 rock lobster and 200 paua on the black market.

The total retail value of the rock lobster and paua combined, if purchased legitimately, was over $30,000.