March 30, 2026 — Anyone walking down New Bedford’s Pier 3 can see the state of the commercial scalloping fleet, rusty trawlers and all. Less obvious are the subtle sheens of “mystery” oil spills leaking into the harbor’s waters.
Trace amounts of diesel and other fossil fuels — especially in older boats — can leak into the vessel’s bilge water and spill into the ocean, where their origins are nearly impossible to trace. These spills can impact water quality and get stuck in the harbor sediment.
At one point, Buzzards Bay Coalition estimated that these so-called “mystery” spills occur in the harbor once every eight days. Coalition President Mark Rasmussen believes that number is likely higher.
“Those are just the spills that are reported,” Rasmussen said. “It’s considered commonplace in a lot of spots of the harbor here to see oil in a way that just doesn’t happen in other places.”
These spills average between 5 and 20 gallons of oil per spill, Rasmussen added.
Although harbor workers and local officials are required by law to report oil spills or visible sheens to the U.S. Coast Guard, these smaller spills often go undetected, Rasmussen said, either dispersing on their own or sinking into the sediment on the harbor floor.
These spills are particularly common among the aging scallop fleet. Many scallop boats are between 30 and 50 years old, making it one of the oldest fleets in the U.S., behind Pacific salmon trolling boats.
The problem is worse in New Bedford than in other ports, in part because it doesn’t have a facility to pump oily bilge out of boats.
The oil pollution also brings up long-term questions: how can New Bedford’s fishing fleet adapt to use less diesel fuel? And someday, could the fishing fleet even go electric?