Alaska salmon, pollock and cod -- seafood products previously exempt from the ongoing trade war between US President Donald Trump and China -- are back on the chopping block, according to Alaska's lawmakers.

On May 23, Alaska's Republican Senator Dan Sullivan wrote US Trade Representative Robert Lighthizer, requesting that the species, yet again, be removed from the 25 percent tariffs Trump has proposed on $300 billion (€267.7 billion) worth of Chinese imports.

"This unanticipated whiplash is creating tremendous uncertainty for our seafood industry in the months ahead, as they attempt to negotiate sales and contracts with the sudden looming threat of new, unforeseen duties on their products," Sullivan wrote.

Sullivan requested the administration specifically remove salmon, Pacific cod, flatfish and rockfish from the tariffs while keeping Alaska pollock on the list.

He said the move to keep pollock on the list would benefit domestic US producers because the product is "predominately Russian-origin."

The Alaska pollock industry has been fighting pollock's tariff exemption since it was put in place last fall, where members of the At-Sea Processor's Association (APA) said the exemption inadvertently gave Russian pollock producers a price advantage on the US market.

"You risk losing critical congressional support support if your actions end up having the result of targeting and harming some of the very Americans we know you want to help -- like hard-working Alaska fisherman who harvest a world class product from our well-managed fisheries," Sullivan wrote.

The letter was also signed by Alaska's Republican lawmakers Lisa Murkowski and Don Young.

The USTR will hold a public hearing on June 17 regarding the new list, according to the agency.