A rough stretch for Cape Cod shellfishermen was to end at sunrise Monday, when the state will reopen the waters of Wellfleet Harbor, 33 days after a norovirus outbreak triggered a shellfishing ban.

The closure, which began Oct. 13, hit at a particularly hard time, coming just days before Wellfleet’s hugely popular OysterFest, a two-day party to celebrate the local shellfishing industry. No raw oysters were served at the event.

The Wellfleet outbreak was part of a one-two punch for the Cape Cod shellfishing industry, coming just a week after unprecedented levels of toxic algae forced regulators to close large areas of ocean south of Cape Cod, including Nantucket and Martha’s Vineyard.

The same toxic algae also triggered closures in Rhode Island and Maine. Massachusetts waters reopened on Halloween.

The closures in Wellfleet came after about 75 people reported getting sick with norovirus after eating at weddings and restaurants on the outer Cape. Many of those afflicted had eaten raw shellfish, prompting the state to order a 21-day closure and a recall of shellfish harvested from the area.

Michele Insley, the executive director of Wellfleet Shellfishing Promotion and Tasting, the nonprofit that puts on the OysterFest, said attendance plummeted 23 percent this year, to 17,000 people, after organizers announced there would be no raw shellfish.

Insley said they considered bringing in raw oysters from other regions, but chose not to do that out of an abundance of caution.

“We had some very, very disappointed people,” Insley said. “The festival has really become an economic driver that has expanded the shoulder season on the Cape. But at that point, we didn’t know the exact source point for the Norovirus. We know it can be transmitted from person-to-person contact, and we know that shellfish can be good carriers, so we didn’t want harvesters out doing raw bars.”

Insley said they considered having no food at all at the festival, but ultimately decided to allow cooked food, including cooked shellfish, to be served.

The sudden closure stung many Wellfleet growers, who depend on OysterFest for a good chunk of their livelihood, Insley said. But the news that the ban has been lifted was welcome news, as the industry enters a heavy harvest season because of holiday demand.

“Oyster sales really take hold around Thanksgiving and through Christmas and New Year’s, so we feel we’re coming back just in time,” Insley said.