The Monterey Bay Aquarium's influential sustainable seafood ranking program has downgraded Chilean farmed rainbow trout to its 'Avoid' list, the latest in a growing list of controversial rankings from the group.

In an updated ranking released Monday, Seafood Watch said it was moving rainbow trout farmed in netpens in Chile's Los Lagos, Magallanes and Aysen regions from its yellow "Good alternative" ranking to a red "Avoid" ranking.

The NGO cited higher use of antimicrobials in rainbow trout farming in Los Lagos -- known as Region X -- for its lower ranking, claiming that rainbow trout farming sites in the region are treated with 1.17