Video by CBF Staff.
I recently spent several days on the Chester River watching concrete from a demolished dam get turned into a new oyster reef. Baby oysters clinging to older oyster shells were placed on top of the concrete bed. The whole operation was fascinating in all sorts of ways. Here are my top 10 interesting facts about the new reef, built by the Chesapeake Bay Foundation with the help from many partners at Swan Point at the mouth of the Chester River:
1. The oyster bed for this reef is 2,800 cubic feet of concrete and granite from the demolished Simkins dam at Ellicott City and two other sources.
2. The Simkins concrete was crushed and screened to 1” to 12” pieces, and cleaned. It was hauled to the oyster site by barge, with water cannons used to blow it over a two-acre site.
3. With the demolition of Simkins and other dams along the Patapsco River, 42 miles of river and 374 miles of tributaries will be opened for passage and spawning by American eel, alewife, blueback herring, and American shad. The American Rivers organization, and the National Oceanic and Atmospheric Administration, spearheaded the dam removals.
4. More than 20 tons of oyster shells were placed on top of the concrete bed at Swan Point.
5. Attached to the oyster shells were about 7.3 million young oysters, or “spat.”
6. Oysters start reproducing early in their lives. Even spat, young oysters of less than an inch, can spawn. During the first year oysters spawn as males, releasing sperm, but in subsequent years as they grow larger, they spawn as females, releasing eggs.
7. Oysters filter and clean water to get nourishment. In the process they remove nitrates. That’s great news for the Chesapeake Bay because it suffers from an excess of nitrogen and phosphorous. An adult oyster can filter 50 gallons of water a day.
8. Being a Bay oyster can be tough. Disease, pollution, and harvesting have reduced the oyster population to less than one percent of the historic population.
9. But there’s good news for oyster survival, too. Last year’s official government survey of Chesapeake oyster beds found the survival rate had doubled from when disease started killing oysters several decades ago. Scientists believe oysters are starting to develop resistance to those diseases.
10. Higher than normal flows of fresh water killed the large majority of oysters in some areas of the Bay north of the Chesapeake Bay Bridge this summer and fall (not uncommon in this section of the Bay directly below the Susquehanna River), but the Swan Point area of the Chester River apparently was unaffected, and looks to be a good home for 7.3 million new residents at Swan Point.