An investigation is underway in Carlingford following claims that up to €500,000 worth of mussels were stolen from the seabed of the Lough.
Gardaí have not confirmed a value of the stock but it is believed to be up to 200 tonnes, which would bring in around €300,000 to €500,000 if sold to restaurants or shoppers.
Gardaí are likely to seek expert advice as part of their investigations. Anyone with information is asked to contact the local Garda Station.
