That pay was something but not enough, said David Andrade, Davy’s father and a co-founder of the shop with his wife. “I’ve been telling the diggers, take it easy, wait for the restaurants to come back,” he said. “But in all reality, you’ve got to make $200 a day to pay for the boat.”

Even these small orders have been helped, Davy Andrade said, by an unexpected form of local generosity: A town resident donated $600 to provide free clams to Andrade’s Catch customers. The donation became the impetus for a retail special: Anyone spending $24 or more on seafood this week received 24 free clams, enough for a pot of chowder. (The donor asked to remain anonymous.)

Even without the special, the shop has still remained busy with sales of other seafood.

Mr. Andrade’s fiancée, Victoria Young, runs an Instagram account that posts daily lists of available seafood, much of which comes from the trawler fleet working in nearby New Bedford, Mass. She also encourages shoppers to place orders by phone and to collect purchases curbside — reducing traffic in the store and potential dangers to the customers and staff.