WASHINGTON (Reuters) – U.S. President Donald Trump signed a memorandum aimed at protecting American lobster fishermen who have found export markets drying up, a senior White House adviser said on Wednesday, adding that China could end up facing new tariffs.

“If those purchase commitments are not met, the United States Trade Representative has been directed to use his discretion to impose … reciprocal tariffs on the China seafood industry,” White House trade adviser Peter Navarro told reporters, referring to $150 million in purchase commitments Beijing made under the so-called Phase 1 U.S.-China trade deal.

In the memorandum, Trump also directed the U.S. Agriculture Department to provide lobster fishermen with the same type of assistance other parts of the agriculture sector are receiving to protect them from harmful trade practices, Navarro said.

He said that assistance would both apply retroactively to harm they have already suffered due to China’s trade practices, and harm they might suffer going forward.

Navarro said the memorandum also called on the U.S. trade representative to come forward with recommendations over the next 90 days on how to address a loss of market share American lobster fishermen have faced due to a Canada-Europe trade agreement that has helped Canadian competitors.

“We’ve seen a tremendous displacement of exports,” he told reporters at the White House.