PARIS — The European Commission said on Tuesday that it was enacting tough trade sanctions against the Faroe Islands after the tiny North Atlantic territory unilaterally increased its herring quota.

The European fisheries commissioner, Maria Damanaki, said in a statement that the European Union was banning the import of herring and mackerel caught in waters under Faroese control, as well as products made from those fish, which make up the greatest part of the territory’s exports. In addition, Faroese vessels will be prohibited from unloading their herring and mackerel catches at European Union ports.

“The Faroese could have put a stop to their unsustainable fishing but decided not to do so,” Ms. Damanaki said. “It is now clear to all that the E.U. is determined to use all the tools at its disposal to protect the long-term sustainability of stocks.”

Fish and fish products make up about 95 percent of Faroe Islands exports, said Gunnar Holm-Jacobsen, director of the Faroese foreign service, worth about $1 billion. The territory exports herring and mackerel worth about $232 million, he said, with about half of that going to the European Union.