Northeast Aquatic Research
74 Higgins Highway
Mansfield Center, CT 06250
860 - 456 - 3179
October 31, 2014
Crystal Lake Association
Ellington, CT 06029
RE: Aquatic Plant Mapping at Crystal Lake in 2014.
Dear Mr. Arzt:
On September 23, 2014, NEAR conducted a comprehensive aquatic plant survey of the
littoral zone of Crystal Lake; the survey did not include exploring either cove.
Survey Results:
1) No new invasive species were found during the survey on September 23, 2014.
2) Variable-leaf milfoil (Figure 1),
a. Milfoil plants were numerous offshore of the town beach in water depths
between 3 and 6 feet deep (see Figure 1). Red points on Figure 1
represent areas where more than one plant was present, these were mostly
outside of areas worked by New England Aquatic Services. Although
most of these plants were laying on the sediment surface, each was long—
greater than 1 foot—and some were at least 3 feet long. Some of the
plants were large and multi-stemmed, indicating that they may reach the
surface in the future. Based on the survey observations, the plants in
Aborn Cove may be seeding the lake with new fragments that are taking
root in the lake outside of the cove.
b. No milfoil was found in the center channel of the outlet cove between the
sandbar and the dam. Along the eastern shore of the cove, we saw three
tiny plants: two were approx. 2 inches tall and the other around8 inches.
c. Several milfoil plants were found offshore of Northeast Cove in about 2-8
feet of water, though much less than was found in 2013.
3) Large-leaf pondweed,
a. No large-leaf pondweed was found in the lake during the September 2014
survey.
b. Beds of large-leaf pondweed identified during prior surveys offshore of
the town beach were not present this season.
4) Red-leaf pondweed (Figure 3),
a. Red-leaf pondweed was most numerous offshore of Northeast Cove, but
less was present in 2014 then was seen in 2013. A couple of plants were
also found offshore of town beach and sporadically in the outlet channel.
Crystal Lake Aquatic Plant Survey
October 2014
5) Recommendations for 2015:
1. Focus milfoil removal efforts on
1)
Plants offshore of the town beach—south side of the lake.
Many plants were found in this area as noted in Figure 1.
Several of these plants were multi-stemmed clumps with long
shoots. Plants were growing in water depths between 3 and 6
feet deep.
2)
Plants offshore of the Northeast Cove-- several small
plants, and clumps of small plants, were found between 2 and
8 feet of water depth.
3)
Removal efforts in Aborn Cove were difficult to
ascertain. Although some areas appeared to have been
cleared of milfoil, large beds of dense plants were still
present. In addition, beds of very small plants covered large
portions of the very shallow sediments near the mouth of
Aborn Brook and toward the shore of the eastern side of the
cove. These plants may be very difficult to remove using
current methods of suction harvesting because the sediments
are deep and unconsolidated. However, some long-term
control is needed because plants in the cove are almost
certainly sending fragments out into the lake, based on the
presence of significant numbers of established milfoil plants
offshore of this area.
4)
Continue to observe milfoil in the outlet channel for
regrowth and remove as necessary. Only very tiny plants
were found in this area, so the outlet channel does not feature
highly on the priority list.
2. Continue to observe the lake for new beds of large-leaf pondweed and
remove as necessary. No large-leaf pondweed was found in lake during
the September 2014 survey. However, new plants are likely to appear in
the future.
3. Conduct a comprehensive lake-wide survey in the fall of 2015.
4. Consider controlling milfoil in off-site ponds that feed to the lake.
Northeast Aquatic Research
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Crystal Lake Aquatic Plant Survey
October 2014
Figure 1 – Locations of variable-leaf milfoil in Crystal Lake September 2014 showing
approximate areas of suction harvesting in 2014 as red highlighted areas
Northeast Aquatic Research
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Crystal Lake Aquatic Plant Survey
October 2014
Figure 2- Locations of variable-leaf milfoil in Crystal Lake October 2013
Northeast Aquatic Research
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Crystal Lake Aquatic Plant Survey
October 2014
Figure 3 – Locations of red-leaf pondweed in Crystal Lake in September 2014
Northeast Aquatic Research
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Crystal Lake Aquatic Plant Survey
October 2014
Figure 4 – Locations of red-leaf pondweed in Crystal Lake in October 2013
Northeast Aquatic Research
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