Windbreaker,
This is a good conservation thread, thanks for starting it.
Tom,
We have never met, but I think you are involved in VA fisheries issues, correct? I have not met Goose or Crow either. I know were Goose lives from his posts and I fish the Severn sometimes, and I think Crow is involved in MD fisheries issues. I hope to meet all of you as well as others on this thread and a lot of other Tidalfishers someday.
The posts on this thread in some ways reflect the different perspective between MD and VA, with the MD portion of the Bay having more freshwater influence and lower salinity and the associated differences in oyster survival. I fundamentally agree with the point Goose made. I think we should be doing everything possible to promote viable populations of native oysters that have disease resistance, but it seems like that may be a more realistic approach in MD waters than it is in most of the VA portion of the Bay and tribs.
New posting on MD DNR page today, seems appropriate to note it in this post:
DNR Biologists Complete Annual Oyster Surveys
DNR Biologists Complete Annual Oyster Surveys
5th Consecutive Year of Good Native-Oyster Survivorship
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Oxford, Md. - Maryland Department of Natural Resources fisheries biologists recently concluded the 2008 oyster survey, an annual assessment of the health and population of oyster bars in Maryland's portion of the Chesapeake Bay. Since 1939, each fall biologists use a dredge to monitor natural oyster bars, seed production and planting areas, dredged and fresh shell plantings and oyster sanctuaries.
"Preliminary results from 2008 indicate that reproduction was poor throughout most of the bay, with the exception of the lower eastern shore areas of Tangier Sound, Honga River, and the Little Choptank River," said Mitch Tarnowski, DNR fisheries biologist. "In general, mortalities and oyster disease levels appear to be relatively low again this year."
During the late 1950's, biologists starting seeing the effects of Dermo (Perkinsus marinus) and MSX (Haplosporidium nelsoni) diseases on the bay's oyster population. While not harmful to humans, these parasitic organisms infect oysters and have lead to the death of up to 90 percent of oysters in some areas. Both diseases thrive in higher salinities, so mortality is much higher in the lower parts of the Bay.
Typically, disease causes the greatest problems during years with higher than average salinity brought about by lower than normal stream flow. With higher salinity in the bay between 1999 and 2002, MSX, Dermo and oyster mortality was higher than average. The relatively wet years between 2003 and 2006 translated to reduced disease pressure and lower oyster mortality.
As part of the 2008 survey, biologists assessed more than 1,800 oysters collected from 282 oyster bars. The dry summer of 2007 did not result in high disease levels similar to previous dry years. Dermo increased in 2007, but remained below normal in both prevalence and intensity. MSX increased in frequency, but for the fifth straight year observed oyster mortality remained low.
"Oyster mortality in 2006 and 2007 were the two lowest years since the 1980's. It's too early to know if this is a trend, but this is a very positive development that we will be monitoring carefully," said Mike Naylor, Director of DNR's Shellfish Program.
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January 13, 2009 Contact: Olivia Campbell
410-260-8016 office I 410-507-7525 cell
ocampbell@dnr.state.md.us
Edit: Goose, our emails crossed in the ether