URI Oceanographers Link Warmer
Water Temperatures
and the Decline of Winter Flounder
Narragansett, RI -- September 13, 2001
-- Biological oceanographers
Aimee
Keller and
Grace
Klein-MacPhee at the University of
Rhode Island’s Graduate School of
Oceanography have conducted experiments on
winter flounder that suggest that the
decline of the species in Narragansett Bay
may be the result of elevated winter water
temperatures.
In a recent study, reported in the
Canadian
Journal of Fisheries and Aquatic
Sciences, Keller and Klein-MacPhee
tested the direct link between warmer
temperatures and the growth and survival
of winter flounder larvae and examined the
relationship between temperature and the
components leading to larval fish. The
study was conducted in the mesocosms of
the
Marine
Ecosystem Research Laboratory at the
URI Narragansett Bay Campus.
Keller and Klein-MacPhee’s study,
funded by a U.S. Environmental Protection
Agency Cooperative Agreement with the
National Academy of Sciences of the
National Research Council, found that the
cumulative impact of warmer temperatures
on the early life history of winter
flounder from hatching through the late
larval stage resulted in 10-16% fewer
larvae surviving to the metamorphosis
stage at 6 weeks.
Winter water temperatures in Narragansett
Bay have significantly increased over the
past 40 years. The warmer temperatures
impact the winter-spring bloom, having an
influence on the availability of food to
higher level organisms. In a previous
study by Keller, she found that the
winter-spring bloom failed to occur in
warm systems, similar to its failure to
appear in the Bay in recent years.
Elevated temperatures may also lead to
increased metabolic activity of potential
predators, leading to increased predation
rates.
Although overfishing plays a role in the
population decline, other factors are
important in controlling the spawning and
survival of winter flounder. Annual
abundance is negatively correlated with
winter temperature, indicating that warmer
temperatures during spawning result in
fewer fish.
"These results, together with the
potential for increased predation as a
result of elevated winter water
temperature, suggest that temperature and
its impact on the predation rate may play
a major role in regulating winter flounder
abundance," said Klein-MacPhee. "Now that
we know that this effect exists, regional
managers should attempt to incorporate the
potential impact of warm winters in their
management plans."
Keller, formerly of Narragansett,
received her B.A., M.S. and Ph.D. from the
University of Rhode Island. She now lives
in Washington state. Klein-MacPhee, a
resident of Narragansett, received her
B.A. and M.A. degrees from Boston
University, and a Ph.D. from the
University of Rhode Island.
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) 874-6642,
lcugini@gso.uri.edu
Back to
GSO
News.
|
