Before #Sustainability was a hashtag or even a buzzword, Chloe Starr ’04 took care in her Science Fair projects to study environmental impact. One year she researched tree rings and another she looked closely at local nitrogen-fixing. Today Starr, an environmental engineer and graduate of the Tufts School of Engineering, is Farm and Wholesale Manager of the Aquacultural Research Corporation (ARC) in Barnstable and Wellfleet.
Speaking to the Falmouth Academy Women in Science & Engineering Club (WISE), she talked about climate change and sustainability.
“Shellfish are actually a carbon-negative product. They remove more carbon from the atmosphere when producing them in comparison to something like beef or chicken who puts more carbon back in. You’re doing good for the world by eating oysters.”
Starr and her crew lease plots in the ocean from local towns. They put baby oysters into mesh bags to keep them in one place and tie them on racks or put them in “hotels” and use the natural wave motion of the ocean to provide a stable food source and keep them clean. The ocean carries nutrients to the developing oysters from algae and the tides keep them clean and free of algae, barnacles, and sponges which dry and fall off in low tide. As the oysters grow, they are split into groups of 30 to 40 bags to give them enough space to increase in size.
Land-based aquaculture such as fish farms, Starr said, pack fish in such tight bundles that they are prone to bacteria and illness. The farms use antibiotics to keep the oysters healthy because if one gets sick, they all get sick. “This is terrible for the animals and the water.”
Ocean-based shellfish farms are far more environmentally friendly, she said. “We don’t use any kind of fertilizer. We don’t use antibiotics and it’s mostly all manual labor. We also don’t have to run big boats or trawlers that use a lot of diesel fuel.”
Because oysters are filter feeders, they filter out algae from the water as they feed. But runoff from things like stormwater, golf courses, and people’s lawns can cause algae blooms due to excess nitrogen. Algae blooms are not good for the water column. Naturally-occurring algae are good for oysters and shellfish, but algae blooms aren't since they deplete the oxygen in the water body. Oysters sequester that nitrogen and carbon into the creation of their shells, so as they process it, they remove it from the water column.
“Since we are out on the water every day, we see the cyclical nature of things and we’ve started to notice quite a bit how climate change is becoming an everyday reality rather than a far-off thing,” said Starr.
“As there’s more carbon in the atmosphere, the oceans become more acidic as they have to absorb more of that carbon to reach equilibrium. Having more acidic oceans is affecting the growth of oyster shells. They don’t grow as well or as quickly, and they’re not as thick and hearty. So, especially in wild populations, you’re seeing more breakage, and the young ones die more frequently.”
Starr said there is a lot of work going on right now to mitigate this and plan for the future. “Can we breed oysters with a harder shell in more acidic water? If the water quality is getting worse closer to shore, is there such a thing as a deeper water oyster farm where the water may not yet have gotten as acidic?”
While winters are getting shorter, the water is not getting as cold as it used to and oysters start to feed earlier in the season. “While not having such harsh winters is good for the survival rate of oysters, it does not bode well for the ecosystem as a whole. I think we’d all rather have harsh winters than deal with what we know is coming,” she said.
Learn more about sustainability efforts and local and regional shellfish at www.archatchery.com
.Photos courtesy of A.R.C. Hatchery