From boaters and shoreline residents to municipal and
regional agencies seeking to protect one of Connecticut’s largest
fresh-water resources, the wide community of stakeholders with an
interest in preserving the ecological balance of Candlewood Lake
will benefit greatly from scientific research conducted this summer
by WCSU students and faculty.
Under the faculty supervision of WCSU Professor
of Biological and Environmental Sciences Dr. Mitch Wagener, Western
biology students are participating in two research projects designed
to explore the environmental impact of invasive plant and mollusk
species that have spread to lakes in western Connecticut. The
studies have been conducted in collaboration with the Candlewood
Lake Authority (CLA), an agency representing the five municipalities
bordering the lake. The CLA has provided a paid internship for
Western senior Catrina Morgan to participate in the research work,
and a $6,000 grant from the Connecticut Department of Environmental
Protection has financed purchase of equipment and supplies for the
A team of four Western biology students
coordinated by Morgan this summer continued a research project
initiated in 2008 to evaluate the effectiveness of a promising
biological tool to control the growth of the pest weed Eurasian
milfoil in the shallows near the shoreline of Candlewood Lake.
Pursuing an innovative
strategy to implant a species of weevils known to damage milfoil
stems, the Ohio-based ecological consulting firm EnviroScience has
continued annual stocking to implant weevil eggs on milfoil stems at
several test sites in an effort to build weevil populations to a
level sufficiently large to control or reverse milfoil
Morgan has worked with seniors Bruna Oliveira
and Heather Shepard and junior Emma Canfield to conduct field and
laboratory studies that have focused on a single test location in a
sheltered cove along the northern shoreline of Candlewood Lake.
Field work requires periodic visits to the cove for snorkel dives to
collect stem samples from milfoil at the weevil implantation site,
as well as milfoil from a designated control site where no eggs were
stocked. The student researchers bring these samples to the Science
Building biology lab for investigation to check for damage to the
milfoil and to identify weevil populations found on the stems.
Wagener observed that research sampling this
year has been conducted at a sheltered cove location because it
offers “a better nursery environment for the weevils and they are
less likely to scatter in the lake.”
Studies to date have provided no clear answer as to whether
the weevil implantations will contain milfoil spread, he added. “In
order for weevils to have an impact, they need to be present in
larger numbers, and we’re not there yet.”
In the wake of the discovery last year of the
zebra mussel species in the waters of Lake Zoar and Lake Lillinonah
— a short distance downstream in the Housatonic River watershed from
Candlewood Lake — the CLA convened a Zebra Mussel Task Force
comprised of representatives drawn from the area community and a
wide range of municipal, regional and state agencies, as well as
WCSU and FirstLight
Power Resources, owner of the Candlewood Lake reservoir and its
power generating facilities.
As a task force member, Wagener participated in
the group’s discussions that produced an interim report in March
offering background on the zebra mussel threat and recommendations
for prevention and control of the spread of the invasive mollusk in
Candlewood Lake and the surrounding area. An important
recommendation of the task force was to establish a program for
early detection and monitoring of zebra mussel presence in
Candlewood Lake, as well as Lake Lillinonah and Lake Zoar.
To implement this recommendation, Wagener has
overseen a research project this spring and summer to collect
plankton in water samples at Candlewood, Lillinonah, Zoar and
Houstanic River test sites on a biweekly basis. Biology seniors
Morgan and Oliveira have joined the research team to provide support
in the field work, using long funnel-shaped nets of fine mesh to
draw up plankton samples for placement in collection jars returned
to the Science Building lab for analysis to determine the presence
or absence of zebra mussel veligers, or larvae.
Wagener has supervised microscopic
investigation of the samples to search for evidence of zebra mussel
larvae. Associate Professor of Biological and Environmental Sciences
Dr. Ed Wong has provided additional support by applying a molecular
genetics technique known as polymerase chain reaction, or PCR, to
reproduce and analyze sections of DNA from the plankton samples.
Wong’s search for DNA sequence matches provides an important tool to
confirm whether zebra mussel larvae are present.
CLA Executive Director Larry Marsicano has
noted that the early detection effort will provide useful
documentation and baseline information concerning the presence or
absence of zebra mussel veligers at various locations in the
Housatonic watershed, as well as early warning of any contamination
found in Candlewood Lake.
Wagener credited the CLA, the Friends of
Lillinonah and the Lake Zoar Authority for important contributions
to the zebra mussel research through their assistance in making
boating and other logistical arrangements to support sample
collection in the field.