Oysters may be small, but collectively they can help improve our oceans.
Farming oysters for food consumption means more oysters cleaning our coastal waters. Restored oyster reefs can help protect shorelines. Let’s learn how these mighty mollusks are so important to our local ocean ecosystems!
How Oysters Can Help Improve Water Quality
A single oyster can filter 50 gallons of water in one day, and an acre of oysters can filter the equivalent of 36 Olympic swimming pools every day! And since you can have too much of a good thing, oysters help by filtering out excess nutrients in the water. Having more oysters in local waters can improve water quality.
With responsible oyster farming management, farmers can supply safe, high-quality oysters year round. The more we eat, the more demand there will be in the marketplace. This increased demand will support local oyster farmers and lead to a higher number of oysters overall in our coastal waters at any given time.
So when you’re looking to dine on a delicious seafood, look for farmed oysters on the menu or at your local fish monger. Even better if it’s a locally farmed oyster!
How Oyster Reefs Can Protect Shorelines
Historical data suggest that until about the early 1800s there was a series of robust oyster reefs that ran from New England potentially to the southern tip of Florida. Records from here in Boston show there were large reefs at the mouth of the Charles and Mystic rivers. In addition to helping filter and clean our coastal waters, these reefs provided a number of other benefits for ecosystems as well as humans.
Like other kinds of reefs, oyster reefs provide a buffer from storm surges. Reintroducing oysters is more important than ever as we now face rising sea levels caused by a warming ocean. Not only would reintroduced oysters provide protection of coastal areas during a storm, they could also provide ongoing protection from the rising sea.
Because they are complex, three-dimensional structures, oyster reefs are also a great habitat for other animals. Restored oyster reefs support the growth of fishes and invertebrates at about 1.46 tons per acre per year! More diverse habitats with more animals are healthier, and this is also great news for other parts of the New England seafood industry.
About 1900, oysters in Boston were thought by some to be extinct. Due to a combination of constructing on ocean fill, pollution, and overconsumption, what were once extensive reefs were all but gone. Luckily for us, they held on despite their severely diminished populations. Despite times of poor water quality, Boston Harbor has come a long way, due in large part to the Deer Island water treatment plant. Boston now has among the cleanest city beaches in the country.
There are also many oyster restoration projects that focus on planting reefs purely for habitat and not for human consumption. Here in Massachusetts, you can check out the work of Mass Oyster Project and even sign up to volunteer with one of its projects!
The Mighty Little Oyster
Oysters are in the group of animals called mollusks, making them related to snails and octopuses. They are what we call bivalve (meaning “two shells”) mollusks, making them most closely related to other shellfish such as clams, mussels, and scallops. There are many different kinds of oysters, but the ones we farm in New England are the eastern oysters (Crassostrea virginica).
Clams and mussels have a “foot,” a muscular appendage with which they are able to move themselves. Oysters do not have a foot and cannot easily move themselves. This is due to the fact that their ideal growing condition is in a reef. Larval oysters settle the best on the shell of another oyster. The shells then will cement together. As this happens generation after generation, eventually a reef forms.