A 200-year-old Wellfleet tradition
Wellfleet has been considered the home of one of the world’s great oyster beds for generations. When Samuel Champlain explored Cape Cod’s waters in 1605, he called Wellfleet Harbor “bay des huitres,” which means “oyster bay.” Over the next 200 years, a thriving oyster industry emerged. But by the beginning of the 1800s, the native oyster population was nearly depleted. Overfishing was the likely cause—oysters were popular not only for eating, but also for use in construction. Disease or habitat destruction may also have been factors.
Aquaculture began in Wellfleet as a result of this depletion crisis. Early on, young oysters were shipped in from Chesapeake Bay because the same species of eastern oyster, Crassostrea virginica, is native to both places. The oysters were fattened and flavored in Wellfleet Harbor and then sold to the lucrative Boston market. Cultivating oysters has been an evolving and enduring part of Wellfleet’s economic life ever since.
One of the greatest contributions to the science of aquaculture was made by a Wellfleetian, David Belding, who studied the local shellfish from his laboratory on the wharf of the Chequessett Inn. In 1911, Belding published a landmark study chronicling the life, growth, and cultivation of shellfish. His findings are still used by modern aquaculturists.
Now, almost 200 acres of Wellfleet’s estuaries are dedicated to grants—pieces of town-owned land that are leased to commercial shellfishermen for oyster and clam farming—and approximately 100 locals are in the shellfishing trade. These commercial aquaculture grant areas exist on several of Wellfleet's beaches, including Mayo Beach, Indian Neck, and Lieutenant's Island and are marked by yellow buoys. The shellfish growing in these areas have been planted and tended by the aquaculturists and belong to them. In 2003, the Wellfleet Shellfish Department estimated that the town’s commercial oyster catch was over 2,250 bushels. At 375 oysters per bushel, close to 850,000 oysters were harvested. This limited production of oysters from such pristine waters makes the Wellfleet oyster a true delicacy.
The town of Wellfleet stocks and maintains a special area on Indian Neck for recreational shellfishing by locals and visitors. A license is required, and it can be obtained at the Beach Sticker building, along with information concerning when and where shellfishing is allowed. Further information is also available from the Wellfleet Shellfish Department. Enforcement of shellfishing regulations is the responsibility of the shellfish wardens.
Spat on the flats
Aquaculturists begin with oyster seed, called spat, which in its first two or three weeks lives a free-swimming existence. Oysters produce huge numbers of eggs and sperm that unite out in the water. The resulting veliger is tiny, only about one tenth of a millimeter long, and its chances for survival are slim. Spat is easily swept out by tides, rain, and runoff, ravaged by temperature changes, or gulped by zooplankton or small fish.
Some growers collect spat in the wild, but many oystermen and women now purchase spat from hatcheries. Under carefully controlled conditions, the shellfish hatcheries replicate the natural spawning of oysters, keeping temperature and salinity constant, protecting the juveniles from predators, and feeding them with microscopic plant cells called phytoplankton. Before sale, hatcheries must certify that the oyster seed is free from diseases that might harm the local oyster population.
Spat finds a home
Regardless of whether it comes from the wild or a hatchery, at the end of its free-swimming life stage, the spat veliger settles to the bottom of the sea. In its new habitat, it seeks a clean, calcareous surface, perhaps attaching itself to an adult oyster.
Some aquaculturists and fishery managers take advantage of naturally occurring batches of spat, called sets, by putting out material to encourage the creatures to attach. To foster oyster settlement, the Wellfleet Shellfish Department deposits cultch, or broken shells, in strategic spots in the harbor where sets have been regularly observed.
While some aquaculturists put out cultch on their farms, others experiment with different methods. One that is becoming popular in Wellfleet is a device called a Chinese hat. Stacked disks of plastic are coated with mortar that has high lime content so that it “tastes” like an oyster shell to veligers seeking a home. These stacks are then placed in areas of the harbor where natural sets occur.
When it finds the right spot, the veliger uses its tiny foot to glue itself to its new home. At this point, the juvenile oyster has transformed itself into a miniature version of a typical adult oyster – even though it’s only about 2/100 of an inch long.
Spat grows up
Sticky secretions from the oyster’s mantle, the soft flesh that lines the inside of the shell, strengthen its bond to the surface to which it is attached. As it grows, the spat uses lime salts in the water to add to its shell, growing out in a fan shape. As it gets slightly larger, the spat starts to form a more obvious bottom shell and grow away from the bottom, although it ultimately remains attached.
Once they’ve grown to about a half-inch, aquaculturists using the Chinese hat method collect their oysters and place them in mesh bags that allow the animals to feed and grow. During the warmer months, growers tend to the bags to keep them clean and to sort the oysters so they’re not too crowded, ensuring they get a good flow of water. As the oysters grow, they must be spread out to new bags, much they way plants growing in a greenhouse need to be repotted. This process involves sorting the oysters by size, so bags contain similar sized oysters. Tending the bags also means removing predators, such as the tiny snails called oyster drills.
In the harsher winter months, some aquaculturists bring their bags into temperature- and humidity-controlled chambers, similar to root cellars, so the oysters will not be harmed by ice when the harbor freezes and thick slabs of ice are churned up by the tides. The shellfishermen who use cultch, however, usually leave the shells on the bottom, allowing the oysters to grow as they do in the wild.
Harvest and environmental considerations
Harvest regulations exist to protect the shellfishery. When oysters are two to three years old and have grown to at least three inches long, they can be harvested. Oysters are sexually mature by this point, so even farmed oysters contribute to the natural populations of oysters around Wellfleet Harbor by spawning before they are harvested. Oysters that meet this minimum three-inch size requirement can be harvested only from town-approved areas and may be harvested only by those who hold a license. Harvesting limits depend upon what type of license is held. Commercial licenses and recreational shellfishing permits may be obtained through the Wellfleet Shellfish Department.
Dragging for wild shellfish can damage coastal habitats, but cultivating or farming oysters and other shellfish as it’s done in Wellfleet is an environmentally sustainable alternative. Shellfish aquaculture does not involve any feeding or fertilizing, so there are no hormone or chemical additions to the bay. The oysters under cultivation simply consume phytoplankton as they do in the wild. As they feed, oysters actually clean the water, each one filtering about 15 gallons of water per day, converting much of the nitrogen they remove from the water into protein. Additionally, oyster beds provide a good habitat for other small sea creatures. Environmentally-aware organizations like Chefs Collaborative and Monterey Bay Aquarium encourage consumers to choose farm-raised oysters.
To market, to market
In order to be distributed to restaurants and food markets, oysters must be processed out of a HACCP-approved facility. HACCP, or Hazard Analysis and Critical Control Points, is a set of federal food handling specifications that ensures freshness and safety.
To the table
Oysters must be kept alive until they are ready to be prepared. They must be kept cool and out of water. Seaweed or damp towels are good packing material, but oysters will die instantly in tap water or even in a bucket of seawater once they have absorbed all of the oxygen in the water. Shellfish that have died before preparation are not safe to eat. For more on handling and preparing oysters, see our Lusty Bit of Nourishment Fact Sheet.
Sources: Woods Hole Oceanographic Institution (www.whoi.edu) and East Coast Shellfish Grower’s Association (www.ecsga.org). For information on environmentally sound fish choices, see www.chefscollaborative.org and www.montereybayaquarium.org. Information about shellfishing in Wellfleet can be found at the Wellfleet Shellfish Department (www.wellfleetshellfishdepartment.org).