His 15-hour work days were cut down to eight, and the number of crab traps he could fish a day was limited to 500. Previously, Marshall had been picking up around 700 traps a day. Certain areas of the bay also became off-limits, and he had to start registering for more commercial licenses. "The money just wasn't there anymore," Marshall says.
He became the first in his family to move off the island in over a century. Marshall and his wife, Quinna, took over his father-in-law's business selling prefabricated chicken houses to poultry farms along Maryland's Eastern Shore.
Leaving the tight-knit community of Tangier was tough for him. "It's like family. You know everyone," says Marshall, who remembers swimming from the docks with friends as a kid.
"I missed crabbing for a long time, probably about five or six years," says Marshall, who used to have a 42-foot-long (13-meter-long) work boat named Fantasy Girl. "I didn't think I would ever get over it. I did it my whole life. You would see the prettiest sunrises and sunsets out on the water. You don't see that on land."
With those days behind him and more young people on Tangier leaving for college or working on tugboats, Marshall wonders if the waterman culture will survive. Today a little more than a hundred Tangier watermen crab full-time, about half the number who were doing it 40 years ago, says Cindy Parks, commercial fishing license agent for the island.
The shrinking waterman population on Tangier reflects a growing trend in small fishing communities all along the Chesapeake Bay. A few decades ago there was an estimated 10,000 full-time watermen who crabbed on the bay. Today there are about 2,500, and that's a figure most people don't expect to see rebound anytime soon.
In Virginia the average age of the waterman is 52 years old, and the state put an indefinite moratorium on issuing new crab licenses in 1999. This makes it difficult for newcomers to break into the business because there are only two ways to get a license: purchasing it from a waterman who is retiring, or getting a family member to pass theirs down.
With crab numbers in the bay at historic lows and state regulations still tight, the future of Tangier is uncertain. More people are finding themselves looking for work off the island just as Marshall did a decade ago, and that's slowly chipping away at the population. When National Geographic published its story in 1973, some 850 people lived on the island. Today there are just 591 residents.
"In 30 years I don't even know if there will be a Tangier," Marshall says. "Everyone is just leaving…and the waterman culture is dying out."