Narragansett, R.I. -- March 26, 2001 --
A two-year survey of Gulf of Maine coastal
waters has revealed the presence of toxic
marine organisms that can lead to
contaminated shellfish and diarrhetic
shellfish poisoning (DSP). These organisms
are present at several sites along the
coast, but pose no immediate concern to
the general public.
GSO biological oceanographers
Lucie
Maranda and
Paul
Hargraves and their colleagues from
the Bigelow Laboratory for Ocean Sciences
and the Maine Department of Marine
Resources collected samples of organisms
associated with mussels and sediments and
found the toxic alga Prorocentrum lima .
Cells of the toxic organism were found at
eleven sites along the coast including a
shellfish nursery site. Although the
survey suggests that the toxic organism is
relatively rare at most sampling stations,
its presence indicates the need for
increased monitoring.
These toxins accumulate in shellfish
that have been feeding on the organisms.
The ingestion of shellfish containing the
toxins can lead to DSP, a severe
gastrointestinal illness in humans.
"We still need a better understanding of
the population dynamics of Prorocentrum
lima, and of the relationship between its
abundance and shellfish contamination
along the coast of New England," said
Maranda. "In the future we plan to work in
close collaboration with shellfish farmers
to find out when and to what extent this
DSP potential could be realized and under
what conditions. The ultimate goal is to
provide adequate information that can be
used for the sensible management of a
resource: protection of public health and
protection of an important fisheries."
In a recent article in the
Journal
of Shellfish Research, Maranda reports
that she was prompted to conduct the study
of Prorocentrum lima as the result of
three incidents pointing to the presence
of the toxic organism in Gulf of Maine
waters.
The first incident occurred in the late
1980s, when several shipments of oysters
originating from Maine and sent overseas
tested positive for DSP and were refused
at a great economic loss to shellfish
farmers. The source of DSP toxins was not
determined and remains controversial. In
1990, the first confirmed DSP event in
North America involved cultured mussels on
the Atlantic coast of Nova Scotia, Canada,
in waters contiguous to the Gulf of Maine.
The DSP toxicity was linked to populations
of Prorocentrum lima. In 1994, the same
toxic organism was found in the Gulf of
Maine in an offshore plankton net sample
collected in the Great South Channel, west
of Georges Bank.
Besides Maranda, other members of the
scientific team include the late Maureen
D. Keller of Bigelow Laboratory for Ocean
Sciences in West Boothbay Harbor, Maine,
John W. Hurst, Jr., Laurie L. Bean, and
Jay D. McGowan of the Maine Department of
Marine Resources, and Paul Hargraves of
the URI Graduate School of Oceanography.
The research was funded by a grant from
the National Oceanic and Atmospheric
Administration.
The URI Graduate School of Oceanography
is one of the country's largest marine
science education programs, and one of the
world's foremost marine research
institutions. Founded in 1961 in
Narragansett, RI, GSO serves a community
of scientists who are researching the
causes of and solutions to such problems
as acid rain, global warming, air and
water pollution, oil spills, overfishing,
and coastal erosion. GSO is home to the
Coastal Institute, the Coastal Resources
Center, Rhode Island Sea Grant, the Ocean
Technology Center, and the National Sea
Grant Library.
Contact: Lisa Cugini, (401) 764-6642,
lcugini@gso.uri.edu
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