A song of praise, and great concern for Crassostrea and us

Why do oysters matter?

Oysters are the proverbial 'canary in the coal mine'.*  What happens to them is likely to happen to us.

The American oyster is amazing. It turn a speck of sand into a pearl, since the mid-19th century it has been an invaluable asset for coastal North Carolina. A single oyster can filter about 1½ gallons of water an hour, extracting nutrients and sediment as they feed. When oysters were at their peak population, they cleansed the waters of the entire coast every few days.

Oysters thrive in the sounds, bays and rivers. Vast reefs of oysters teem with sea life, an essential habitat and refuge. An area of one square yard can support as many as 5,000 oysters.

Oysters are a very good indicator of the overall health of coastal Carolina, and what's good for the oyster is good for the rest of us.

That's why its so disturbing to witness the gradual disappearance of the eastern oyster, crassostrea.

Oysters and the reefs they create have declined by 99% in North Carolina since the early 20th century.

Oysters are dying because our coastal ecosystem is grossly out of balance. We have changed the salinity of the near-coastal waters by our habits of ditching wetlands, and hard surface paving which allows stormwater runoff to rush straight to the sounds in large amounts instead of filtering through soils and grasses first.

Runoff is polluting water with nutrients, bacteria and heavy metals. Miles of wooden bulkheads leach out their poisons. The oxygen in coastal creeks, rivers and sounds is becoming more often depleted, leading to large stretches of 'dead water'.

There was a time in North Carolina when the estuaries were clean and the oysters were plentiful. Native Americans gathered at many areas up and down the coast and left piles of oyster shells in piles of two acres, piled 7-8 feet high.

As recently as 100 years ago, oyster reefs were so massive that they posed a navigational hazard to ships. The Swiss writer, Michel, wrote in 1701:

"The abundance of oysters is incredible. There are whole banks of them so that the ships must avoid them. A sloop, which was to land us at Kingscreek, struck an oyster bed, where we had to wait about two hours for the tide. They surpass those in England by far in size, indeed they are four times as large. I often cut them in two, before I could put them in my mouth."

With the expansion of the railroads in the mid-1800s, new markets began to open because oysters could be shucked, iced and sold in markets hundreds of miles away. With more oyster fishermen at work, the oyster harvest climbed as high as 27 million bushels a year during 1880 - 1910. Oysters quickly became a common and affordable food throughout the eastern and Midwestern states.

In 1880 there were about 38,000 oystermen, but by the end of the 20th century about 4,300 oystermen were able to harvest only 5.9 million bushels.

All shellfish waters undergo sanitary surveys to determine the amount of contamination and bacteria, primarily fecal coliform.

About 1.43 million acres are open to shellfishing in North Carolina, another 364,000 acres are permanently closed, and another 50,000 acres 'conditionally open' shut down temporarily during periods of heavy rain with consequently heavy runoff.

(Thanks to the folks at the North Carolina Coastal Federation for their '2002' State Of The Coast' report)

Oysters and Our Estuaries

	Wetlands play an important part in the coastal ecosystem. They help control flooding by absorbing rainfall and releasing it slowly. One acre of wetland can store 1½ million gallons of floodwater. Wetlands also filter out organic wastes and other pollutants, improving water quality, and serve as nurseries for fish and shellfish. Unfortunately, almost half of North Carolina's wetlands have been lost due to the greed of forestry operation operators and urban developers.
	Agricultural runoff is the leading cause of non-point pollution. Nutrients and pesticides are channeled into sensitive waters by storm water. Agricultural runoff has contributed to the impairment of almost 60% of the state's polluted waters.
	UNC-Wilmington researchers have concluded that as little as 10% impervious surface coverage (paving) degrades the quality of the stream into which it drains. 30% coverage devastates the water quality of the receiving water body. Most existing residential developments contain surface coverage of 20-50%.
	Between 1990 and 1996, NC Division of Coastal Management authorized construction of more than 133 miles of bulkheads that eliminate the shallow water habitat critical to the ecohealth of the estuary, and wooden bulkheads slowly release into the water the chemical preservatives and poisons that prevent wood decay.
	Runoff from streets, sidewalks and parking lots accounted for 39% of the polluted water, and with that runoff comes harmful bacteria, which accounted for 41% of the polluted acres in our state's estuaries.
	Unfortunately, recreational and commercial boating pose risks to the ecosystem, not only from wake erosion of the water's edge, but also the petroleum contaminants that find their way into the water from exhausts and spills, and the poisons released from boat bottom anti-fouling paints.

Civil War Oyster

To supplement the diets of tens of thousands of federal troops operating in the watershed, quartermasters harvested oysters from the Bay. Likewise, the 30,000 Confederate prisoners interned at Fort Point Lookout at the mouth of the Potomac River stayed alive by foraging for oysters. When these soldiers returned home, they took a taste for oysters with them. The Bay's oyster industry grew after the war to meet this new demand. Over time, demand outstripped supply to such an extent that, today, most of the oysters are gone.

In the olden days, miners who went deep into coal shafts used to carry a golden canary with them into the chambers below. The miners, usually people who had spent their entire lives in the depths of mining shafts, were unable to sense when toxic gasses were escaping from the walls. The rule was simple, if you looked over and saw that the canary was laying on its side with "Xs" for eyes, you knew it was time to run as fast as you could towards an elevator.