PORTLAND – A longtime fisherman who owns five trawlers is bringing to the city a 380-foot freezer ship that will allow fishermen to target New England’s healthy herring and mackerel stocks.

American Freedom is due to arrive later this week in Portland Harbor after more than $24 million in upgrades at shipyards in Norway and Poland, according to Jim Odlin, president of American Pelagic Seafood, which owns the boat.

The freezer ship will allow smaller fishing boats to pursue offshore fisheries now targeted by larger vessels, he said.

Odlin said his “mother ship” will provide an opportunity for struggling operators of trawlers that target cod and haddock to supplement their incomes by catching and unloading high-volume fish that are plentiful.

“That may be enough to get them over the top so they’ll continue to have a viable business,” Odlin said Monday.

American Freedom, which left Europe two weeks ago, will use fish caught by about 20 vessels, Odlin said.

Two or three of Odlin’s five trawlers will help support the operation, and the rest of the fish will come from independent vessels that aren’t equipped to catch and refrigerate large quantities of fish, he said.

It’ll be the first mother ship operation in four or five years in New England waters, and the first U.S.-flagged operation, he said.

In the past, Russian factory ships have partnered with local trawlers, but those operations ended as onshore processing operations grew, said Lori Steele, fishery analyst with the New England Fishery Management Council.

The herring stocks, in particular, have been at record levels in recent years after recovering from a collapse in the 1960s, she said.