Editor’s note: This story was updated on Jan. 30.
In Maine’s warmer waters, oysters grow briny and firm, feeding on algae and plankton. Their cycle from hatchery to bay is only as successful as their location. Known as filter feeders, oysters’ size and flavor is fully reliant on the nutrients available in the water surrounding them.
Water depth, temperature and circulation set the stage for ocean ecosystems and can shift dramatically within a few miles; Maine’s coastline measures about 3,400.
This fickle business has grabbed the attention of University of Maine researchers and aquaculture specialists working to strengthen Maine’s blue economy.
NASA and U.S. Geological Survey satellites have been recording temperature and other data from Maine’s waters for years. Using that, UMaine researchers are developing an online tool that will allow growers to click on a coastal location and receive an estimate for oysters’ time-to-market. Prospective farmers are already using an early version that shows average sea surface temperatures in locations throughout the Gulf of Maine since 2013.
“Oyster growth relies on two things: food availability and temperature,” said lead researcher Tom Kiffney, a postdoctoral researcher at UMaine’s Aquaculture Research Institute. “Our model combines data on both to make a prediction about how long it would take oysters to grow. It takes some risk away when selecting a future farm site.”
Kiffney and Damian Brady, professor of marine sciences at UMaine, combined resources from the NASA-USGS Landsat satellite and the European Sentinel-2 satellite to form the foundation of their upcoming online tool and most recent study, published in the journal Aquaculture. Their model is able to predict how quickly eastern oysters reach market size by feeding it information on sea surface temperature and organic matter.
They analyzed 10 years of Landsat data from 2013-23 to establish average temperature patterns along the coast, while Sentinel-2 imagery added estimates of chlorophyll and nutrient presence. Brady said they validated the model against seven years of field data to prove its accuracy.
“To get an aquaculture lease is a long and arduous process,” Brady said. “Once you get a lease, you cannot simply move it somewhere else, so getting as much information about your site up front is crucial.”
Diversifying Maine’s blue economy
An industry that has increased in value 78% between 2011-21, oyster farming has become one alternative to catching lobsters. While oysters will likely never reach the lobster industry’s peak of $750 million, Brady said it has the potential to grow into the tens of millions of dollars.
He added that diversity in Maine’s blue economy makes it more resilient to change and allows people who work on the waterfront to have alternative options for revenue if one aspect of the coastal economy experiences disease or habitat changes, such as those faced by lobster populations in recent years.
Lobster and oyster culturing also occur in different environmental conditions, further diversifying Maine’s coastal economy. Lobsters thrive in colder waters, whereas oysters — while able to grow in a range of conditions — grow faster in warmer waters.
Oysters also aren’t resource limited like lobsters, whose populations fluctuate year to year depending on the ecosystem. Oysters are able to be cultivated as long as there is space in the water that is available and permissible.
In addition to creating a web tool that will be widely accessible to oyster farmers, the researchers help teach workshops through Maine’s Aquaculture in Shared Waters program on how to interpret and apply temperature and water clarity data to sites.
Read the full story on NASA’s website.
Contact: Ashley Yates; ashley.depew@maine.edu
