September 3rd, 2014

Published by Anna Farrell on

Eelgrass Committee Minutes (Click here to see a PDF of the Minutes with handouts)

Frenchman Bay Eelgrass Meeting
9-3-2014
MDIBL Davis Classroom
3-5 pm

Present: Terry Towne, Jenn Fortier, Chris Petersen, Anna Farrell, Jirias Charabati, George
Kidder, Jane Disney, Hamish Stevenson, James O’Donnell.

We started with introductions. Terry represents Maine Coast Heritage Trust, Chris Petersen,
College of the Atlantic professor and vice-president, Frenchman Bay Partners, Anna Farrell and
Jirias Charabati are both AmeriCorps Environmental Stewards at MDIBL, George Kidder and
Jane Disney are staff scientists at MDIBL working in the Community Environmental Health
Laboratory, and Hamish Stevenson and James O’Donnell are MDIHS students who are working
with Billy Helprin at Maine Coast Heritage Trust and who are interested in doing independent
study work in Environmental Science.

1. George Kidder presented his work on side scanning sonar. He presented background on
how side scanning sonar works as well as recent results. The handouts are appended to
these minutes.

The raw readout from the Lowrance system shows the result of 10,000 “pings” through the
transducer. The computer program being used to analyze the scans is from the Army Corps of
Engineers. It allows for the calculation of percent cover and canopy height. The program can
correct for tide height. Then, coordinates can be exported to GIS and visualized on a map. Points
are colored according to plant density. An example from near Stave Island shows that some
eelgrass is present where it was mapped historically. The ultimate goal is to be able to map
eelgrass around the bay each year using this system.

2. Jane presented an overview of the summer. Handouts are appended to these minutes.
Jane discussed the need to report out our progress in some way that is accessible to people. All
of our work may not be publishable in peer reviewed journals but will still be important for
partners to see.

She set the context of the work in summer 2014. Last summer (2013) eelgrass did not come up
in the upper bay. The reasons are still unknown. It may have been a variety of stressors
including green crabs. Then winter 2013-2014 was very cold and may have killed off a lot of
green crabs.

Eelgrass was transplanted in 5 areas in upper Frenchman Bay. The first restoration project took
place in Berry Cove. Four 8 ft. x 32 ft. crab exclusion fences were constructed in the water.
Grids were placed inside and outside of the exclosures. We will be checking in on the status of
plants this fall.

We did some incidental trapping, and since crab numbers seemed low, we did not construct
fences at other sites during the summer.

Funding from Army Corps of Engineers has not been released. State partnership in the eelgrass
restoration work is being required; the state must co-sign a cooperative agreement or Army
Corps will withdraw the grant. While trying to sort this out, MDIBL moved forward with project
partners.

We tried using two different wooden biodegradable grids this year. One had a wooden frame
with strings with ties for securing eelgrass. The other had a wooden frame with burlap into
which eelgrass was woven.

In addition to deploying wooden grids with eelgrass at Berry Cove, Hadley Point, Thomas
Island, Jordan River, and Goose Cove, other methods were tested. “Restoration runners” made of
burlap weighted with sandbags were deployed at Hadley Point and in Jordan River. Eelgrass
was tied onto metal washers and dropped at Hadley Point and in Jordan River as well. We tried
tying eelgrass onto rocks and dropping in Goose Cove in Trenton.

Anna presented “Restoration By the Numbers”, including how many volunteers, volunteer hours,
grids, and plants were involved in restoration this summer.

Jane reviewed the work of two interns at the Community Environmental Health Laboratory.
Alden Dirks studied the eelgrass from sites around MDI and tried to find anything that would tell
us why eelgrass is so abundant and doing so well in outer parts of Frenchman Bay but not in
upper Frenchman Bay. He compared plant abundance, biomass, composition, and tensile
strength. He found that these attributes varied among sites. He looked at the correlation between
these attributes and water quality variables. The only significant correlation that he found was
between plant biomass and nitrate levels in the water column.

Because silicate seemed to be lower in the upper bay in the last several years, it was
hypothesized that there might be a relationship between plant abundance or plant biomass, or
even tensile strength of plants and levels of silicate in the water column or in the plant tissue
itself. But these correlations were not found. An abstract of Alden’s work is attached to these
minutes.

In a tank experiment, where silicate (in the form of wollastonite) was added to three tanks with
eelgrass and not to three control tanks, no difference was seen in plant strength, or biomass, or
rhizome and root biomass. There was no difference in silicate levels in the water column either,
despite additions of wollastonite. We are waiting to find out if there are differences in the
amount of silicate in the plant tissue. This was a short term study that may require more time.
Alden and Mary mapped eelgrass in all of their study sites. It was suggested that areas without
eelgrass be mapped as well, or that we create a frame around the area in which mapping was
done, so that in the future we know if the mapped area was the full extent of the eelgrass or just
the area studied.

Jane mentioned that dried plant material will be sent off for analysis of cellulose and lignin,
which are indicators of plant strength. We will see if levels correlate with tensile strength, or can
in any other way explain the success of eelgrass in some areas but not others.
On a positive note, eelgrass seedlings are coming up around Hadley Point. This might mean that
eelgrass can come back in an area even after being absent for a full year.
Mary Badger studied the genetics of green crabs from around MDI and found that both northern
and southern varieties of green crabs could be found at all locations and that there was no
correlation between the proportion of crabs with northern haplotypes and eelgrass abundance. An
abstract of her work is attached to these minutes.

In order to assess whether differences in eelgrass abundance could be attributed to crab
abundance, a crab survey was conducted in the last week in all of the eelgrass study sites around
MDI. Preliminary results show that crab abundance does not seem to influence eelgrass
abundance or biomass. Preliminary data are attached to these minutes.

3. Jane then presented Anecdata.org and encouraged everyone to use the website to initiate
projects, add to existing projects, etc.

4. Next Steps:
a. The fencing will be removed from the Berry Cove restoration site next week. The plants
on several grids from inside and outside of fenced areas will be assessed. Chris P.
suggested looking at crab numbers inside and outside of the fence before removing the
fencing. If eelgrass looks good inside and outside of the fences, we will skip the crab
trapping effort.
b. In order to assess whether seedlings at Hadley Point are truly seedlings and not coming
up from rhizome remnants, we will take a closer look at the area. We plan to determine
shoot density in the area as well. Chris suggested planting some seeds in a test plot and
seeing if the seedlings look like the shoots we have at Hadley Point. This may help us
determine the source of these shoots at Hadley Point.
c. We will communicate with mussel harvesters to appreciate their cooperation, let them
know that shoots can come up even after a year with no growth, so that eelgrass areas
without eelgrass also need to be protected.
d. We will frame in eelgrass areas on GIS maps so that we know the extent of our mapping
efforts in 2014.
e. We may present findings at the Acadia Science Symposium in October.
f. Jane will follow up on the Army Corps Grant