Oyster Restoration Seen as Essential
for Future Habitat

by Mike Crowe

The Northeast Regional Planning Body met to review a draft of the Regional Ocean Policy for the Northeast in Durham, NH, October 20, 2015. It is likely the last workshop meeting before a larger semi-annual meeting November 16 & 17 in Portland, Maine. (nrpb.org) The last meeting will be in the spring of 2016. Maine DMR graph

The oyster, a rare delicacy today until relatively recent times, was as common as the sardine.t is, like the sardine, a keystone species on which other marine species and habitats depend on. The American oyster (Crassostrea virginica) is making a comeback due to the efforts of scientists, shellfish aquaculturist, and citizens who recognize the importance of the oyster and the reefs in restoration of the coastal marine habitats, as we lost 85% of the natural oyster habitats globally (Beck et al 2011).

After enjoying a productive and sustainable life on the coasts of the northern hemisphere for 18 million years, the intensive human industrial harvesting and pollution of coastal areas have brought the oyster and their habitats to the brink of total collapse in the evolutionary blink of an eye. In that blink, the memory of this once omnipresent coastal monitor and seafood delight has been erased. The one-time scale and productivity of oyster reefs is difficult to comprehend when compared to today’s nearly extinct wild oysters.

Rhode Island. Growing out oysters in protective wire cages. Low tide reveals the oysters in one of their development stages. Most oysters are two to three years old and about 3 inches long when they go to market. At this stage they have not reach reproductive maturity, but are considered the most marketable to consumers. Bob Rheault photo

Pre-Columbian Native Americans enjoyed abundant oysters for centuries and left deep shell piles (middens) along the New England coast—most notably in Damariscotta, Maine, at the Whaleback Shell Midden, which consists primarily of oyster shells. It is located on the east side of the Damariscotta River. Other shell middens are located on the estuary in both Damariscotta and nearby Newcastle. The middens in this area were formed over about 1,000 years between 200 BC to AD 1000. Originally, the Whaleback midden was more than thirty feet deep, more than 1,650 feet in length, and a width varying from 1,320 to 1,650 feet. It got its name from its shape.

America’s oldest restaurant is the Union Oyster House in Boston, MA (note: it was supported by the oysters harvested from the near by Mystic river estuary, today the most polluted part of the Boston Harbor). It is surrounded by a handful of 18th and 19th century buildings that survived 1960s urban “renewal” bulldozers. Built near the shore in the 1700s, today the Union Oyster House building is more than a quarter of a mile from the edge of Boston Harbor. (Maine oysters are on the menu there.) That relocation is part of the story behind the oyster’s demise in the northern hemisphere. The shoreline, not the building, moved as the coastline was filled in, taking with it estuaries, salt marshes, eelgrass and oyster reefs—all critical nursery habitat for a wide range of interconnected marine species, including the “sacred” cod.

Another method of growing oysters out to market maturity. Cages suspended from cables where oysters filter feed in the water column. They can also be grown directly on the bottom and harvested there. In restoring oyster reefs the oysters are left to reach reproductive maturity and build mass vertically. This mass of shell and internal passages becomes a protected feeding area for many other species. The reef as a whole becomes a protective barrier against coastal storm surges. Bob Rheault photo

The scale of the oyster fishery was reaching the heights of harvesting when Ernest Ingersoll published his 300-page opus, The Oyster Industry in 1881* (Department of the Interior-10th United States Census. The History and Present Condition of the Fishery Industry – The Oyster Industry, Washington: Government Printing Office, 1881). One schooner in one day in 1870 harvested 1.5 million oysters from the Wellfleet Harbor. In 2015 the harvest for the entire year there was 7.5 million, mainly from aquaculture, while 1.4 million from commercial oyster harvest.

Before Europeans arrived there in 1600s there were oyster reefs in what Europeans recognized as harbors, because those harbors were estuaries the best areas for human settlements. Estuaries are places where rivers meet the sea, they are nurseries for fish, shellfish and a wide range of animals and plants. Oysters clean the water and produce food for other sea life. “Oyster reefs are the coral reefs of the northern hemisphere,” said marine biologist Dr. Anamarija Frankic.. She added that the Texas coast 100 years ago was embraced by reefs 6-7 feet high that ran for miles Blasting oyster reefs to allow ship passage in harbors was common practice in past centuries. Increasingly industrial-scale mechanical oyster harvesting and man-made pollution in a very short time brought one of nature’s crowning achievements to its knees. “We all need to give Mother Nature a leg up through an interdisciplinary effort to restore the oyster,” said Kahren Dowcett, Director of the International Oyster Symposium 6.

Today, many of us know that disregarding nature in this way is an eventual dead end. However, most of us have forgotten or have never known how rich and truly self-sustaining our marine resources and coastal systems once were. The oyster is a good example of how quickly we are able to forget an essential and enormous structural component of a resource upon which we ultimately all depend.

Before image is from 2011. The town of Wellfleet, MA on Cape Cod designated a 2-acre area in Duck Creek for oyster restoration. Wellfleet Harbor had been a very productive area for oysters. It had no oysters when this photo was taken.

The 6th biennial International Oyster Symposium (IOS) was held in Falmouth, Massachusetts on Cape Cod on October 21-23. Since being established, the IOS has met in world capitals where the oyster has had a long cultural and economic presence. The IOS was started in Japan by Dr. Katsuyoshi Mori, a leading marine biologist. The World Oyster Society, which established the IOS in 2005, has on its website the following mission statement: The Mission of the World Oyster Society is to be an instrument of goodwill, friendship and cooperation for all who have some linkage to oyster research, production and use anywhere in the world.

After image: Cultch (shells) were placed as suitable substrate for natural spat settlement. Two years later image shows an established oyster population of 5.8 million oysters. If the environmental conditions are suitable for oysters, they would establish reefs within several years if the area is closed for shellfishing. A sustainable oyster habitat could be developed within 5 years if working with nature.

IOS spokesperson Dowcett said the goal of this symposium was to promote interdisciplinary interests to advance oyster aquaculture and oyster restoration around the world and to foster an understanding of the importance the oyster and the general public. It is the only conference in the world solely devoted to the oyster. Dowcett said it is noteworthy that the symposium was held in Falmouth, Cape Cod. “The oyster has played a significant role in Asian culture, medicine and the life of the people for 4,000 years. We have a lot to learn from oysters regarding its adaptive properties given all the changes Earth has gone through over millions of years,” said Dowcett.

The World Oyster Society promotes both oyster cultivation and wild oyster restoration. The restoration is necessary for the ecosystem services the oyster provides to maintain water quality and nursering habitats for many marine species. Filter-feeding oysters (one adult oyster ~50 gallon of water /day) clean the water. Dawcett said it’s important to bring leading thinkers together to restore this keystone species to support the survival of the oceans. (repetitive) “People are beginning to recognize the importance of the oyster and the services it provides,” she said.

Rhode Island oyster farmer Bob Rheault said he has seen the almost immediate return of other species after putting out a half dozen oyster cages over what had been devastated bottom. In southern New England, wastewater treatment plants and the decline of forests have resulted in a lot of bottom being buried in mud that limits sea life habitat. Oyster cultivation has been restoring some of that bottom.

Marine biologist Dr. Anamarija Frankic, Director of the Green Harbors Project, said there is a need for restoring the oyster beds ,which would improve coastal water quality, increase biodiversity and protect our shorelines from storms and erosion, as well as adapt to sea level rise. Water quality and shellfish monitoring and testing determine where and how shellfish can be harvested or where shellfish aquaculture can be practiced, she said.. However, Dr. Frankic, explained that it is important to extend monitoring of the sea food to many other pollutants including heavy metals, pharmaceuticals, persistent organic pollutants, pesticides and nano-plastics that remain in the water column and bioaccumulate in the seafood. Wastewater plants cannot remove these pollutants from the water.

Setting up an oyster buffet on a bed of crushed ice. Most oysters are consumed fresh in restaurants and at buffets. Shucking oysters requires a some technique, practice and a special knife. Demand for oysters in the U.S. has grown rapidly in recent years. Rhode Island oyster grower Bob Rheault said oyster harvests have doubled in the last 5 years and demand is growing faster than supply. Bob Rheault photo

Ocean acidity may be the biggest gorilla in the ocean health room today. Dr. Frankic said that the shells of shellfish—calcium carbonate—should be recycled back into the coastal systems, which together with oyster reef restoration could potentially mitigate ocean acidification (oysters can act as ‘tums’), Marine dead zones in many parts of the world, 400 at last count, are the result of man made pollution, including excess fertilizers. These zones have grown explosively in the last 50 years, said Frankic. More recently, biogeoscientists have found that many of these dead zones are larger and deeper, and that the pH of the water there is double what was previously thought (visit earthobservatory.nasa.gov/IOTD).

Frankic said we, humans need to listen and learn from nature. There are oyster restoration efforts underway along the east coast, in Wellfleet, Orleans and Boston, Mass., New York, San Francisco and the Gulf of Mexico. “We want to replicate oyster habitat on a small scale, cove by cove.. There is no single recipe or a guide book, as every place is unique. Fishermen provide amazing recourses and scientists and the public need to include the traditional knowledge in the research projects and solutions” she said.

Rheault said the number of oyster farms in Massachusetts has grown rapidly over the last decade, as has the market demand for oysters. Massachusetts has 77 oyster farms, 6 hatcheries and 580 acres of bottom being used to cultivate oysters. Rheault said there are well over 500 named oyster suppliers today in the United States.

At the turn of the nineteenth century, American oysters were regularly shipped to European capitals like Paris because they were considered the best in the world. A large percentage of the oysters shipped to the world were harvested in in New York Harbor as late as the 1920’s. A single oyster can filter 50 gallons of water in a single day. Restoration is not just about restoring oysters. It is about the species and systems that relied on the oyster to have a chance to survive. These organisms, along with oysters, are an integral part of the web of life in the ocean.

The restorative power of the oyster is demonstrated in the return of fin fish species to Boston Harbor, said Frankic. The new sewage treatment system had a huge positive effect, as we are not dumping sewage directly into the harbor, so the nature has the capacity to restore it self, as nature is resilient she said.

Most people know the oyster as the two- to three-year-old, 3-inch-long shellfish served on a half shell in restaurants. But oysters can live from 30 to probably 80 years and grow to 12 inches long. The 2-3-year-old oyster appeals to the market because of its size and it is easy to eat. Frankic questions the viability of inducing the rapid oyster reef restoration the ocean needs given the practice of consuming so much of the oyster population before it reaches sexual maturity.

Anamarija Frankic founded the Green Harbors Project, which seeks to restore natural coastal habitats including oyster reefs as no take zones, salt marshes and eel grass beds based on biomimicry principles, in New England estuaries and harbors. (www.umb.edu/ghp)

More on oysters:

http://worldoyster.org/vision_e.html

Estuary Video: https://www.estuaries.org/estuary-science#zonesofanestuary