less turbidity, more light is transmitted through 

 the water, expanding areas of submerged aquatic 

 vegetation (SAV), an important nursery habitat for 

 a variety of species. 



"The health of North Carolina's oyster 

 populations is a good indicator of the overall 

 health of our estuaries; all prudent measures 

 should be taken to ensure a viable oyster 

 resource," according to a DMF report. 



In North Carolina, oysters are found from 

 the extreme southeastern end of the Albemarle 

 Sound near the northern end of Roanoke Island 

 southward through the Croatan, Roanoke and 

 Pamlico sounds to the estuaries of the southern 

 part of the state to the South Carolina border. 



Since before recorded history, the oyster has 

 been an important source of food in coastal North 

 Carolina. When the first Europeans arrived they 

 were amazed at the number of oysters found. 



The Carolina oyster industry hit its ascent 

 in the 1 880s, when Baltimore companies built 

 larger canneries in coastal towns. Schooners 

 from outside North Carolina introduced oyster 

 dredges and longer, sturdier tongs into the local 

 oyster industry. Despite later attempts to restrict 

 dredging, most of the damage to oyster beds 

 already had occurred by 1910, according to DMF. 



In the 1960s, ecological changes began 

 affecting oyster harvests. Harmful intrusions 

 — disease and polluted waters, combined with 

 other factors — have tainted the once prolific 

 resource. 



In recent years, there has been a decline in 



the number of leases for oysters. In 2003, the state 

 issued 273 leases in comparison to 294 in 1993, 

 according to DMF. The highest density of leases 

 is on the Newport River in Carteret County and 

 Stump Sound in Onslow and Pender counties, 

 according to Hardy. 



OYSTER DISEASE 



Since the late 1980s, Dermo (Perkinsus 

 marinus) has been responsible for major oyster 

 kills in North Carolina. Harmless to humans, the 

 parasite wears down oysters over many months, 

 killing them before they reach a harvestable size. 



The disease first hit the Pamlico Sound in 

 the early 1990s, explains Hardy. 



"Since then, it has spread up and down the 

 coast," he adds. "Dermo seems to be driven more 

 by climatic and salinity-driven issues. From the 

 late 1980s to 2002, North Carolina had drought 

 conditions that provided warm, dry winters, 

 where the water temperature didn't drop, and the 

 salinity was high. Dermo, like oysters, thrives in 

 medium salinity water." 



There also have been isolated incidents of 

 MSX — a parasite that typically thrives in cooler 

 waters north of North Carolina. 



A combination of environmental factors 

 has forced the closing of many oyster beds. Of 

 1.43 million acres of North Carolina salt water 

 suitable for shellfishing, more than 365,000 acres 

 have been closed for shellfish due to pollution, 

 according to Hardy. 



To address the oyster crisis, DMF adopted 



an oyster management plan in August 200 1 . 



"We are in the process of incorporating 

 recommendations," says Hardy. DMF staff 

 members have identified areas where only 

 hand-harvest methods will be allowed to provide 

 protection from the effects of mechanical harvest 

 gear, he adds. 



"Hand-harvest gear usually does not 

 damage undersized oysters that must be returned 

 to the bottom, where they were caught, nor the 

 structural integrity of the reef system or oyster 

 rock, to the degree that mechanical methods do," 

 Hardy explains. 



In recent years, research on oyster disease 

 has gained momentum. 



Through funding from the National Sea 

 Grant College Program, Charles "Pete" Peterson, 

 of the UNC-Chapel Hill Institute for Marine 

 Sciences, and Sean Powers, now of the Dauphin 

 Island Sea Lab in Alabama, are studying the 

 influence of local small-scale variations of land- 

 scape setting on Dermo and Eastern oysters. 



"A lot of native oysters in North Carolina 

 have been lost to disease in the last 20 or more 

 years," says Peterson. "We hope this research 

 will help the oyster industry get back on their 

 feet." 



In previous Sea Grant studies, Peterson 

 examined the influence of large-scale envi- 

 ronmental factors on oyster disease, including 

 salinity and temperature. The scientists found 

 that there were lower incidences and less severity 



Continued 



COASTWATCH 9 



