THE VIRGINIAN-PILOT
Copyright (c) 1994, Landmark Communications, Inc.
DATE: Wednesday, July 27, 1994 TAG: 9407270403
SECTION: LOCAL PAGE: B5 EDITION: FINAL
SOURCE: NEWPORT NEWS DAILY PRESS
LENGTH: Medium: 82 lines
Oysters 1, Humans 0.
Scientists are scrambling to figure out how approximately 40 sterilized Japanese oysters in the York River suddenly became fertile.
``As best as anyone can tell, this is a previously unreported phenomenon,'' said Eugene M. Burreson, an oyster scientist at the Virginia Institute of Marine Science in Gloucester Point. ``It was so unexpected. Now we're struggling to understand it.''
Until they do, researchers assume they will not be allowed to place non-native, sterilized creatures into the Chesapeake Bay.
The story of Japanese oysters in the York began last summer, when 200 were sterilized and placed in the river, where the oysters were tested to see if they could resist two strains of parasites that kill most native oysters in the Chesapeake Bay.
If Japanese oysters were found to resist the parasites, maybe scientists could figure out how they did it and help native oysters do the same.
By October, scientists began drawing conclusions from their test: None of the Japanese oysters was infected by MSX, one of the parasitic strains. And dermo, the other strain, infected only 25 percent of them slightly.
But something strange happened in November.
Blood tests on some of the oysters showed that one of them now had the ability to reproduce. The sterilization process somehow had been reversed.
``We thought it was a mistake,'' Burreson said. ``Then we sent some more to be tested.'' By February scientists confirmed that about 40 of the 200 Japanese oysters in the York either had reversed the sterilization process or were close to doing so. Because it was the middle of the winter and the water was cold, the oysters could not spawn. But they were taken out of the York anyway.
Rutgers University geneticist Standish Allen, who developed the sterilization process, is baffled. Allen, who is working in France until December, could not be reached for comment.
Oysters 1, Humans 0.
Scientists are scrambling to figure out how approximately 40 sterilized Japanese oysters in the York River suddenly became fertile.
``As best as anyone can tell, this is a previously unreported phenomenon,'' said Eugene M. Burreson, an oyster scientist at the Virginia Institute of Marine Science in Gloucester Point. ``It was so unexpected. Now we're struggling to understand it.''
Until they do, researchers assume they will not be allowed to place non-native, sterilized creatures into the Chesapeake Bay.
The story of Japanese oysters in the York began last summer, when 200 were sterilized and placed in the river, where the oysters were tested to see if they could resist two strains of parasites that kill most native oysters in the Chesapeake Bay.
If Japanese oysters were found to resist the parasites, maybe scientists could figure out how they did it and help native oysters do the same.
By October, scientists began drawing conclusions from their test: None of the Japanese oysters was infected by MSX, one of the parasitic strains. And dermo, the other strain, infected only 25 percent of them slightly.
But in November, blood tests on some of the oysters showed that one of them now had the ability to reproduce. The sterilization process somehow had been reversed.
``We thought it was a mistake,'' Burreson said. ``Then we sent some more to be tested.'' By February scientists confirmed that about 40 of the 200 Japanese oysters in the York either had reversed the sterilization process or were close to doing so. Because it was the middle of the winter and the water was cold, the oysters could not spawn. But they were taken out of the York anyway.
Rutgers University geneticist Standish Allen, who developed the sterilization process, is baffled. Allen, who is working in France until December, could not be reached for comment. But he told the Bay Journal, a publication that devotes itself to the Chesapeake Bay, ``There was no reason to think, when the study began, that this would happen. There is no precedence for it in the animal kingdom that I've been able to find.''
Allen's sterilization process involved bathing oysters with a chemical that forces them to maintain an extra set of chromosomes. Any spawning by these oysters, Allen figured, always would result in an abnormal fertilized egg that either dies or becomes an abnormal oyster larvae, which would soon die. by CNB