NEW BEDFORD — For the next four months, the Norpel plant on Fish Island will operate around the clock to freeze and box whole mackerel bound for Nigeria, Egypt, Poland and other foreign markets.

The strong-tasting fish has yet to win an audience among American eaters, but foreigners enjoy it smoked, grilled or pickled.

The mackerel season begins in January, when fast-swimming schools of the green and blue tiger-striped fish can be found in Southern New England and Mid-Atlantic waters.

Norpel's fleet of four trawlers (the company owns three vessels and contracts one) hunts for the fish in pairs, towing a large net through the middle of the water column. During one tow, the 165-foot vessels catch between 450,000 to 650,000 pounds of mackerel, depending on the size of the net and the size of the school of fish, said Norpel general manager Billie Schofield.

The plant can process up to 700,000 pounds of mackerel in 24 hours, he said.

During the 12- to 18-hour trip from the fishing grounds, the cold-water fish are stored in tanks of refrigerated seawater. Back at port, giant tubes pump the fish and seawater from the ship to storage tanks located inside the plant.
Unlike groundfish that are filleted and sliced before freezing, mackerel are frozen with their heads, tails and fins intact.
"We don't do anything to it," Mr. Schofield said.

Norpel's goal is to freeze the fish as quickly as possible to lock in freshness, he said.

While other East Coast plants use 24-hour blast freezing techniques, Norpel uses vertical plate freezers that freeze a 53-pound block of fish in four hours.

The $25 million plant, which became operational in January 2003, is one of the largest processors of pelagic fish in the United States. Pelagic fish live in the middle of the water column or near the surface of the ocean.

During the mackerel season, Norpel employs about 70 workers per day. Mr. Schofield estimates that the company's fishing and processing operations contribute between $30 million to $50 million per year to the city's economy, due in part to food, gear, vessel supplies and packaging purchases from local vendors.

The freezing process begins with workers who sort the mackerel by size as the fish slides down a conveyor belt. The fish weigh between 5.3 to 17.6 ounces and measure 10 to 14 inches in length.

The conveyor belt carries the fish into a cold, sterile room where the pipes are lined with frost. The fish slide off the belt into subdivided containers that freeze the mackerel into a square block. The block of fish is then mechanically sealed in a bag and placed in a cardboard carton. Ships transport the cartons in bulk to customers around the world.

When frozen, the mackerel have a body temperature of negative 20 degrees Fahrenheit, Mr. Schofield said. It takes more than 24 hours for the block to thaw at room temperature.

In Nigeria, vendors at outdoor markets thaw the mackerel at their stalls and sell it fish by fish.

"It's an inexpensive protein," Mr. Schofield said, noting that mackerel sells for less than 50 cents per pound.

Atlantic mackerel is managed by the Mid-Atlantic Fishery Management Council using an annual quota system. In the late 1960s, foreign fishing fleets "heavily exploited" the stock, according to the National Oceanic and Atmospheric Administration. Foreign fleets have since been barred from U.S. waters.

Today, mackerel is not subject to overfishing. The agency reports that the spawning stock biomass — the weight of fish that are old enough to spawn — has increased steadily since 1978.

When the mackerel season ends in early May, the Norpel plant will take a short break before the herring season, which runs from June to November. The plant also freezes herring, using the same vertical plate freezers.

Contact Becky W. Evans at revans@s-t.com
January 14, 2008