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  • Sean P. McNally, Brianna Shaughnessy

Sustainability and Sustainable Intensification of Oyster Production

Global Sustainability

The term “sustainability” came to recent prominence when it was defined by the Brundtland commission in 1987 as development that “meets the needs of the present without compromising the ability of future generations to meet their own needs” (For further reading, see Brundtland 1987). This is playing out on a local level with the rising popularity in products that are sustainably produced in an environmentally friendly manner.

Recent news about population growth demands, along with climate change, are fueling a push for more efficient utilization of resources and sustainable approaches that are in line with the Brundtland 1987 definition. This current global condition calls for an overhaul of food production strategies as well as improving resources for alternative sources of protein, leading to an increased focus on innovative sustainable food solutions. In our Gulf of Maine region, sustainability labels are being applied to fisheries and aquaculture, with an increasing number of labels being used from producer to retailer.

The human population will continue to increase with estimates that by 2050 we will have over 9 billion people on the planet. This population will require significantly more food, and the United Nations Food and Agriculture Organization (FAO) estimates that global aquaculture production will need to increase 250% by 2030 just to maintain current global per capita fish supplies. How can such an ambitious target be achieved, while maintaining any semblance of “sustainability”?

From the North American perspective, there is a concerted effort to increase seafood production and consumption, with the caveat that consumers want a sustainable product but do not want to pay high prices. As noted, aquaculture production is one means to increase the amount of seafood in the marketplace that meet these standards. Since the harvest of wild species (both freshwater and marine) cannot sustain any significant increase, aquaculture is perceived to have the “greatest potential to meet the growing demand for aquatic food,” as noted by FAO.

Globally, markets are specifically turning to aquaculture to help achieve future food demands in a sustainable manner. In their most recent 2016 report, FAO reported that in 2014 the production of aquatic animals from aquaculture surpassed global wild-caught fish contribution for human consumption for the first time. Total aquaculture production amounted to 73.8 million tons globally, with an estimated value of $160.2 billion. More importantly, in terms of food security and the environment, this 2016 report estimates half of the world’s aquaculture production of animals and plants is comprised of non-fed species (i.e., filter feeding species like bivalves, molluscs, and seaweeds). Such aquaculture products can help mediate coastal impacts as they can remove nitrogen from the water and help to increase water quality. Additionally, non-fed species and multi-use crop ocean-cultivated products are attractive to a wide variety of industries, spanning markets for food, dietary supplements, bioremediation, and even energy.

The commercial practice of shellfish aquaculture, specifically oyster aquaculture, arguably offers one of the best avenues to meet this goal while also meeting the needs of a sustainable practice. The requirements for shellfish aquaculture at scale are high quality waters, unimpeded and free access to a leased site, exclusivity of that site, and environmental integrity.

Oyster Production

Globally, oysters are the second-most produced animal (by group) in aquaculture. Regionally, oysters are the key production species in Massachusetts where shellfish production (oyster and quahogs) has increased 660% between 2004 and 2017.

The Massachusetts coastal zone is composed of 78 coastal communities, 1,500 miles of shoreline, and 2,500 square miles of oceanic and estuarine systems. In 2017, there were 390+ shellfish growers on 1,300 acres. Their social license or acceptance is generally positive as they are renowned for their water filtration abilities and are associated with a time gone-by when water quality was greater, in part from expansive oyster reefs. This is exemplified by a “green” rating by the Monterrey Bay SeaFood Watch Program.

While oysters offer important functions for a healthy ecosystem, what is the maximum number that should be produced in each community? This move towards greater production while maintaining ecosystem function is referred to as sustainable intensification.

To understand sustainable intensification in the Massachusetts oyster industry, it is important to understand why farmers select to operate their farms at their specific densities, why they select to grow animals to the specific sizes, and how these decisions impact the overall farm profitability.

In Massachusetts, the coastal zone is considered public space for multiple sector use, i.e., fishing, swimming, navigation, recreation, etc. However, shellfish aquaculture presents a challenge as it does not fall under the public trust doctrine. Thus, the community, residents, and land owners can have a significant voice in determining where oyster aquaculture activities can be sited based on their concerns.

Yet an important component of sustainable intensification is to balance the environmental impacts within a social operating space. Not all stakeholders within Massachusetts have equal optimism for oyster production. Some bristle at the aesthetics of a working waterfront, or the gear in the water, while others are concerned that ecosystem function is not being maintained. This can result in negative backlash at public meetings, and a differing philosophy as to the aesthetic impact of various production practices.

Massachusetts is interesting from a sustainable intensification standpoint in that there is a three-fold difference

between low- and high -density oyster plots. This difference is ultimately influenced by the methods local farmers employ as well as the local perception of the overall sustainability of oyster farming. And herein lies the challenge – everyone has a personal idea about what constitutes sustainable food production. How can it be quantified so that the needs of the growers, the local community, and the environment are all respected?

At this time, we have no definitive answers. Researchers across the globe have been investigating sustainable intensification for a large number of products. However, the Gulf of Maine environment and its residents are unique enough that solutions used elsewhere should be adopted with caution.

The Gulf of Maine is warming faster than almost 99% of the world’s oceans. This in itself deserves our attention and action, but it also has consequences for food production as it affects natural seafood resources. From the need to create more food to locating food production near urban centers, we might look to the inherent benefits of aquaculture as a solution to our future sustainable food challenges.

For more information on aquaculture sustainability, see


Sean P. McNally is a PhD candidate at UMass Boston Intercampus Marine Science & Technology program working with Dr. Michael Tlusty. His studies within Dr. Tlusty’s lab focus on examining state and municipal permitting systems and how to integrate new technologies into current aquaculture siting, monitoring, and regulation schemes.

Brianna Shaughnessy is a PhD Student in Environmental Biology at UMass Boston. Prior to joining Dr. Jarrett Byrnes' lab as a Coasts and Communities Fellow, she completed a Master of Professional Science through Northeastern University's Three Seas Program. Her past research focused on surveying kelp forests with the purpose of assessing the impacts of global change on such critical ecosystems. As a native of Cape Cod, MA, an integral part of Brianna's upbringing involved constantly questioning and developing a deep respect for coastal communities. Her current research focuses on the development of sustainable fisheries practices in hopes of acting as liaison between the community that raised her, and the scientists aiming to understand and protect it.

Dr. Michael Tlusty is an Associate Professor of Sustainability and Food Solutionsat UMass Boston. His work and that of his students focuses on linking science, technology, and innovation to transform the world's aquatic food systems by working to create more, waste less and do a better job producing what we already produce. Working collaboratively with stakeholders across all sectors to support and advance practical and sustainable solutions to the issues facing our aquatic food systems

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