Can Oysters Save New York Harbor?

Overview

On April 26, 2012, Science & the City at the New York Academy of Sciences, hosted Can Oysters Save New York Harbor?, the first installment of the Locavore's Dilemma series. The series of seminars explores the various issues encountered by New York locavores—those who only consume food produced locally. Oysters, once a staple of the local cuisine but long since depleted, are experiencing a steady resurgence in New York Harbor, thanks in great part to the concerted efforts of the Oyster Restoration Research Partnership. This meeting explored the progress towards, challenges to, and consequences of rehabilitating the oyster population of the Harbor. The meeting started with a presentation from student interns from the New York Harbor School on their Oyster Restoration Project. Then, Andrew Revkin, award-winning journalist and author, moderated a panel discussion and Q&A session.

Derek Thompson, Florence Bloomfield, and Alimot Yusuff, aquaculture student interns at the New York Harbor School, presented an overview of the school's collaborative restoration efforts. The Urban Assembly New York Harbor School (known as the Harbor School) is a public Career and Technical Education high school located on Governor's Island whose curriculum is built around the central mission of restoring the marine environment of New York City. The school was founded in 2003 and has grown to be a pivotal partner in the oyster restoration initiative in New York. The students gain valuable experience in every stage of the process, learning about everything from the bureaucratic and legislative requirements of permit applications, to the science of oyster breeding and the engineering of anchoring reefs. To date, a total of 1 million oysters have been grown by the school, and half a million have been anchored to five reef sites in the New York Harbor.

The students explained that oysters have become central to their mission because of the bivalves' positive impact on the ecosystem. Oysters are keystone species, crucial to the ecology of the environment, and disproportionately so, relative to their number. They are also exceptional for their bio-filtration capabilities: consuming algae, organic matter, and pollutants; thereby producing cleaner water. A single oyster can filter up to 50 gallons of water per day. Oysters also form densely packed oyster reefs that serve as a nursery and foraging habitat for various species of fish and for a variety of invertebrates, helping to support biodiversity.

The original oyster population (in the trillions) in New York Harbor was depleted as a result of several factors, largely because of industrialization. The Clean Water Act of 1972, regulating water pollution, has provided a framework for mitigating the threats against the oyster population. However, several obstacles still challenge oyster restoration efforts. In part because of shoreline engineering, strong currents are often present in inlets around the Harbor. These currents are harmful to growing oyster populations as oyster larvae, known as spats, need to attach securely to a hard substrate in order to develop fully. The students at the Harbor School address this by incubating and growing oyster larvae in a controlled nursery environment before attaching the densely packed oysters onto reef sites.

To stimulate oyster spawning to produce the spats, which occurs during the spring in the wild, the students place oysters in a large tank and gradually increase the temperature over a few weeks. Fertilization occurs externally: the spawning oysters release their gametes into the water (broadcasting), and the presence of gametes in the water stimulates other oysters to spawn at the same time (synchronously). The students then separate gametes by sex and combine them to mate.

Spat-on-oyster shells, grown at New York Harbor School, ready for deployment onto oyster reef. (Image courtesy of Alimot Yusuff, Florence Bloomfield, Derek Thompson, and Denzel John)

The New York Harbor students also grow algae for the oysters. As they grow, the oysters are fed two species of algae, one each from the genera Tetraselmis and Isochrysis, for a varied diet. These organisms are photosynthetic and require similar care as terrestrial plants. After fertilization, the oyster larvae undergo several stages. In the veliger stage the larvae utilize their cilia to create currents for feeding and locomotion. In their pedi-veliger stage, which comes next, larvae search for a substrate on which to grow. The students utilized crushed oyster shells as a substrate and explained that it is important to incubate the oysters during this period. In the wild, feeding and attachment is much more difficult because of strong currents. Once the oysters reach the spat-on-shell stage, where they have developed a shell, they are ready to be deployed.

The students then discussed their recent efforts in the field. They are now growing oysters in Wallabout Basin, in Brooklyn Navy Yard. This location is generally suitable because it is protected from strong currents and is located by the East River where the exchange of water will provide a good food source for the oysters. However, the students remarked, this area is plagued by a problem common in the Harbor: Combined Sewage Overflow (CSO). In many older cities the sewage system was designed to collect both waste water and storm runoff jointly. When the combined sewage and storm water volume exceeds a treatment plant's capacity the system overflows excess waste water directly into surrounding bodies of water (without treatment). In New York City it only takes a tenth of an inch of rainfall to cause CSO. The bacteria introduced by CSO are detrimental to the oysters as they compete for the oxygen in the water. The students concluded their presentation with a general reflection on the unique opportunities they have at the Harbor School.

Andrew Revkin, world-renowned environmental journalist, echoed the students' excitement for their work as he picked up the second half of the event, praising the unique multidisciplinary effort that invigorates the Harbor School's initiative. He was joined by Kate Orff, a professor and landscape architect whose studio SCAPE launched "Oyster-Tecture," a unique ecology and urban design initiative that uses oyster reefs to reshape and clean the inland shoreline along Governor's Island. Pete Malinowski, founder of the aquaculture and oyster restoration program at the Harbor School, and Paul Greenberg, award-winning author, also joined the discussion.

The panelists presented a rich history of the oyster and its ecology in New York and explored various themes as related to these fascinating bivalve creatures. While acknowledging the human-induced decimation of the oyster population in New York in the last century (before 1900 the average New Yorker ate 600 oysters each year), Greenberg was resistant to focusing the narrative on the usual lamentations of the ills caused by past actions. Instead, his view was optimistically forward facing. As a result of the Clean Water Act, oysters have the opportunity to thrive in the Harbor again.

Shifting the discussion, Orff presented what oyster restoration can do to revitalize public space by reengineering shoreline. Hard shorelines and strong currents, damaging to oyster reefs, also discourage recreational use of water spaces. Hard shoreline engineering, used to control erosion and flooding at the shoreline through structures such as concrete slabs and bulkheads, often causes erosion down-coast and has been shown to adversely affect wildlife. By coordinating conservation and urban design approaches, we can, Orff noted, design spaces that use humans and oysters both as agents and as beneficiaries of change. Initiatives can increase the oyster population, and oyster reefs can act as wave attenuators that make shorelines more accessible for recreational purposes.

Panelists also discussed the evolving role and perceptions of the oyster industry. Historically, oysters have been enjoyed as a food source. As a result, the oyster industry grew quite powerful across the country. They fought for environmental regulations that would protect their asset, the oyster. Greenberg mentioned that the first waste water treatment plant in the country came about in Baltimore because of the oyster industry's demand for it to ensure the safety of the oysters. That power has since waned. Now, rather than initiating regulation to protect oysters from human-created toxins, the oyster industry is experiencing resistance from health regulators who seek to protect people from the potential health hazards of eating wild oysters.

Greenberg believes regulators may view oysters as an attractive nuisance—a legal doctrine that holds landowners responsible for injuries to children injured while trespassing on land if the injury is caused by a hazardous object that attracted the children to the land and if the children are unable to assess the risk associated with that object. Greenberg disagrees with applying this perspective to the oyster situation as it infantilizes the population. To combat against the 'risk' of humans being drawn to eat oysters they might encounter in the wild, the panelists agreed that the solution is simply to clean the water. They believe the onus is on regulators to crack down on CSO and other polluters, rather than on the oyster producers. Malinowski recognized that the Department of Environmental Protection has demonstrated some commitment to reduce CSO waste by 35%–40% over the next 5–10 years by pledging $6 billion to the effort. However, he said, much more needs to be done, and he hopes that by raising awareness he and others can spur greater investment that would enable further reductions in CSO waste.

Panelists were hopeful that environmental policy in New York would help oyster restoration efforts. Orff pointed to examples of success in Maryland as motivators. There, she remarked, an integrated government initiative with clear organizational structure has proven effective. Greenberg held hope that perhaps, as with many other things, New York could become the beacon for oyster restoration projects around the country, saying of an oyster "if [it] can make it here, [it] can make it anywhere."

Use the tab above to find multimedia from this event.

Media available from panel discussion featuring:
Moderator: Andrew C. Revkin (Journalist)
Panelists: Paul Greenberg (Author), Pete Malinowski (Marine Science Aquaculture teacher), and Kate Orff (Landscape architect)
Student presenters: Florence Bloomfield, Denzel John, Derek Thompson, and Alimot Yusuff (Aquaculture Intern, Oyster Restorer NYHS)

A video podcast about the New York Harbor School project is also available.

Presented by

The Harbor School

Pace University