HomeMy WebLinkAboutPerera Pond - 2025 YER
December 1, 2025
Yarmouth Conservation Commission
1146 Route 28
South Yarmouth, MA 02664
Sent via email: bdirienzo@yarmouth.ma.us, kbrooks@yarmouth.ma.us
Re: Perera Pond, Yarmouth Port, MA – 2025 Year End Report (DEP# SE83-2142)
Dear Ms. DiRienzo, Ms. Brooks, and Commission Members,
It is our pleasure to present a year end summary report regarding
the 2025 Aquatic Management Program at Perera Pond (Figure 1).
The pond is approximately 0.4 surface acres and is located in
Yarmouth Port, MA. This waterbody is surrounded by two homes
with a saltwater marsh to the north. A slim barrier of shrubbery and
larger vegetation act as a buffer between the houses and the
shoreline to the Pond.
Historically, Perera Pond has battled nuisance densities of aquatic
native vegetation species (Potamogeton sp.) and algae, with
occurrences of invasive species common reed (Phragmites
Australis) and Japanese knotweed (Reynoutria japonica) during the
2025 season. The goal of the 2025 program was to manage the
invasive species and nuisance densities of native species/algae
while monitoring basic water quality through a proactive monthly
schedule. This would be accomplished by implementing an Aquatic Management Program that focused
around performing all applicable tasks, including planning, permitting, surveys, treatments, and
reporting.
During each visit to the pond, a survey was conducted
using visual observation paired with a standard throw -
rake and handheld GPS/ArcGIS Field Maps, as applicable.
Additionally, dissolved o xygen (DO) and temperature
readings were collected throughout the season using a
calibrated YSI meter with optical sensor. Dissolved
oxygen is the amount of oxygen in water that is available
to aquatic organisms. DO is necessary to support fish
spawning, growth, and activity. Tolerance varies by
species, but the figure shown provides a general range of
fish tolerance (Source: epa.gov). Dissolved oxygen can be
affected by many outside factors, such as: temperature, time of day, and pollution. Dissolved o xygen
levels are typically lowest early in the morning. Healthy water should generally have concentrations of
about 6.5-8+ mg/L. All readings are included in tables throughout this report.
Figure 1: Perera Pond – Yarmouth, MA
Figure 2: Dissolved Oxygen Table
All permitting, treatments, and survey tasks were completed without issue and at the proper times. The
table below provides the specific dates of each task. Below the table, each visit/task performed is
described in additional detail.
Summary Of 2025 Management Activities
Date Task/Description
May 21, 2025
A pre-treatment survey was conducted to gauge the baseline condition of the
pond and to document species/densities; Initial algaecide treatment was
performed; Aeration system was inspected
June 13, 2025 Post-treatment survey was conducted to assess t he effectiveness of the
previous treatment; Aeration system was inspected
July 16, 2025 A survey performed to assess the conditions of the Pond; An herbicide
treatment was performed; Aeration system was inspected
August 27, 2025 A survey was performed to determine treatment areas; An upland invasives
treatment and an algaecide treatment was conducted
September 9, 2025
An end of season survey was conducted to assess the effectiveness of the
2025 management program and guide recommendations for 2026; A follow-
up upland treatment was performed
May 21, 2025 – Pre-Management Survey / Algaecide Treatment
On 5/21/25, Aquatic Field Biologist, Brian Sweeney, and Field
Biologist, Irini Stefanakos, made a visit to Perera Pond. Upon arrival
to the site, a survey was conducted using visual observation paired
with a standard throw-rake and handheld GPS/ArcGIS Field Maps, as
applicable. Plants documented during the survey are documented in
the table below.
Species Identified
Common Name Latin Name
Filamentous Algae
Common Waterweed/Elodea Elodea canadensis
This site visit included a survey and algaecide treatment as well as
basic water quality data collection. Filamentous algae was
documented and treated during the site visit. There were no
restrictions associated with this treatment. Both aerators in the pond were fully functioning as well. Water
clarity was slightly below average due to recent weather events but dissolved oxygen levels were within
an average range. We would continue to monitor and treat as necessary for the remainder of the season.
Figure 3: Filamentous algae observed
along the shore of Perera Pond during
May visit
A treatment was conducted for the control of algae. The liquid contact algaecide was applied using a
treatment boat equipped with a calibrated sub-surface injection system. This application methodology
allows for even coverage within the treatment areas. T he treatment was completed without issue.
Temperature & Dissolved Oxygen
Surface Temp (℃) Surface DO (mg/L)
12.8 7.95
Secchi Disk Clarity
Secchi Disk Depth (Feet) 1’4”
June 13, 2025 – Post-Treatment Survey
On 6/13/25, Senior Aquatic Biologist, Colin Gosselin, made a visit to
Perera Pond. Upon arrival to the site, a survey was conducted using
visual observation paired with a standard throw -rake and handheld
GPS/ArcGIS Field Maps, as applicable. Plants documented during the
survey are documented in the table below. (*) denotes an invasive
species. Invasive species are non-native to the ecosystem and are
likely to cause economic harm, environmental harm, or harm to
human health.
Species Identified
Common Name Latin Name
Cattails Typha
Common Reed* Phragmites australis
Common Waterweed/Elodea Elodea canadensis
The site visit consisted of collecting basic water quality and completing a survey. Overall, the pond looked
excellent. The aeration unit was working properly. No algae present at the time of inspection. A small
population of immature common reed was near the far end of the pond, but the other stands appeared
to be under control. A small healthy patch of cattails (Typha sp.) was also present.
Temperature & Dissolved Oxygen
Surface Temp (℃) Surface DO (mg/L)
22.4 8.97
Figure 4: Perera Pond’s shoreline during
June visit
July 16, 2025 – Mid-Season Survey / Herbicide Treatment
On 7/16/25, Aquatic Field Biologist, Brian O'Leary, and Aquatic Field
Biologist, Jake McNary, made a visit to Perera Pond. Upon arrival to
the site, a survey was conducted using visual observation paired with
a standard throw-rake and handheld GPS/ArcGIS Field Maps, as
applicable. Plants documented during the survey are documented in
the table below. (*) denotes an invasive species. Invasive species are
non-native to the ecosystem and are likely to cause economic harm,
environmental harm, or harm to human health.
This site visit to Perera Pond
consisted of a survey and the
collection of basic water quality
data. Water clarity was average at
the time of visit. The average depth
of the pond appeared to be around 2 -3 feet, with a maximum depth of approximately 4 feet 3 inches ,
measurements requested by the Perera Family. Dissolved oxygen levels were high, but appropriate
considering the plant assemblage. Moderate densities of thin-leaf pondweed (Potamogeton pusillus) and
elodea (Elodea canadensis) were noted throughout the pond. Sparse densities of duckweed (Lemna) lined
the shorelines, along with a few mature purple loosestrife (Lythrum salicaria) plants along the eastern
perimeter. A couple patches of both cattails and invasive phragmites were also noted. No significant algae
blooms were observed within the pond. Additionally, no Japanese knotweed was observed around the
pond at the time of visit, but fox grape bushes were noted along the eastern shoreline.
Due to the state of the vegetation within the waterbody, an herbicide treatment was conducted in order
to curb the presence of any near-nuisance density elodea and thin-leaf pondweed. The treatment was
guided by day-of-treatment survey data and excellent c overage was achieved within the target area of
the western edge. This treatment would help to facilitate a healthier aquatic environment within Perera
Pond. Weather conditions were optimal for treatment. We w ould continue to monitor the pond's
condition and treat as/if necessary throughout the remainder of the season.
A treatment was conducted for the control of target nuisance/invasive plant growth. The liquid contact
herbicide(s) was applied using a treatment boat equipped with a calibrated sub-surface injection
system. This application methodology allows for even coverage within the treatment areas. The
Species Identified
Common Name Latin Name
Common Waterweed/Elodea Elodea canadensis
Cattails Typha
Common Reed* Phragmites australis
Duckweed Lemna
Purple Loosestrife* Lythrum salicaria
Thin-leaf Pondweed Potamogeton pusillus
Fox Grape
Figure 5: Perera Pond during July visit
treatment was completed without issue. We anticipated plant die-off within just a few days to a few
weeks.
Temperature & Dissolved Oxygen
Surface Temp (℃) Surface DO (mg/L)
32.4 14.17
Secchi Disk Clarity
Secchi Disk Depth (Feet) 4'3" (to the bottom)
August 27, 2025 – Phragmites Treatment / Algaecide Treatment
On 8/27/25, Aquatic Field Biologist, Jake McNary, made a visit to Perera (114 Wharf Lane). Upon arrival
to the site, a survey was conducted using visual observation paired with a standard throw -rake and
handheld GPS/ArcGIS Field Maps, as applicable. Plants documented during the survey are documented in
the table below. (*) denotes an invasive species. Invasive species are
non-native to the ecosystem and are likely to cause economic harm,
environmental harm, or harm to human health.
This site visit included the collection of basic water quality data, a
brief survey of the pond and its shoreline, an upland invasive species treatment, and an algaecide
application. The survey was conducted to assess overall plant diversity and species assemblage. Several
upland invasive species were observed, including phra gmites, purple loosestrife, Japanese knotweed,
Asiatic bittersweet (Celatrus orbiculatus), and multiflora rose (Rosa multifora). These species were treated
where found. However, some patches of Asiatic bittersweet located within predominantly native plant
areas were left untreated to protect desirable vegetation.
Following the upland invasive treatment, an algaecide application was performed in response to dense
mats of algae observed floating on the water’s surface. Brittle naiad (Najas minor) and duckweed were
also present in the pond. Brittle naiad which had been treated during the previous visit, appeared mostly
Species Identified
Common Name Latin Name
Purple Loosestrife* Lythrum salicaria
Common Reed* Phragmites australis
Cattails Typha
Asiatic Bittersweet* Celastrus orbiculatus
Japanese Knotweed* Reynoutria japonica
Multiflora Rose* Rosa multiflora
Brittle Naiad* Najas minor
Filamentous Algae
Duckweed Lemna Figure 6: Upland invasives treated
during the visit
dead or showed visible signs of decline. The health of the pond would continue to be monitored
throughout the remainder of the season to track treatment outcomes and inform future management.
A treatment was conducted for the control of invasive phragmites and various upland invasives. The liquid
herbicide was applied using foliar application methodology. Phragmites and target species in low densities
and/or plants in close proximity to non-target native species were individually hand-wiped to
minimize/negate any non-target impacts. These methods allow for even and precise coverage. The
phragmites were accessed either on foot or via boat, as most applicable. Weather was also closely
monitored prior to treatment to ensure a treatment date without rain or high winds.
A second treatment was conducted for the control of algae. The liquid contact algaecide was applied using
a treatment boat equipped with a calibrated sub-surface injection system. This application methodology
allows for even coverage within the treatment areas. The treatment was completed without issue.
Temperature & Dissolved Oxygen
Surface Temp (℃) Surface DO (mg/L)
27.6 14.45
September 9, 2025 – Post-Management Survey / Upland Treatment
On 9/9/25, Senior Aquatic Biologist, Colin Gosselin, made a visit
to Perera Pond. Upon arrival to the site, a survey was conducted
using visual observation paired with a standard throw-rake and
handheld GPS/ArcGIS Field Maps, as applicable. Plants documented
during the survey are documented in the table below. (*) denotes an
invasive species. Invasive species are non-native to the ecosystem
and are likely to cause economic harm, environmental harm, or harm
to human health.
Species Identified
Common Name Latin Name
Common Reed* Phragmites australis
Japanese Knotweed* Reynoutria japonica
This site visit consisted of collecting basic water quality data,
conducting a brief survey of the pond and shoreline, and performing
a follow-up foliar herbicide treatment targeting phragmites and Japanese knotweed. One small stand of
Japanese knotweed and a larger stand of phragmites were treated using a backpack sprayer, with
thorough coverage achieved. If left unmanaged, these invasi ve species can displace native vegetation,
reduce habitat diversity, and alter shoreline hydrology; targeted control helps maintain ecological
Secchi Disk Clarity
Secchi Disk Depth (Feet) 2’3 (to the bottom)
Figure 7: Knotweed observed during
September visit
function and access. Overall, the pond was in very good condition. The previous herbicide/algaecide
treatment appeared effective, with no nuisance plant growth or algae observed. The aeration unit
was operating properly, and the water level was full and st able.
A treatment was conducted for the control of invasive phragmites and Japanese knotweed. The liquid
herbicide was applied using foliar application methodology. When in low densities and/or plants in close
proximity to non-target native species were individually hand-wiped to minimize/negate any non-target
impacts. These methods allow for even and precise coverage. The species were accessed either on foot
or via boat, as most applicable. Weather was also closely monitored prior to treatment to ensure a
treatment date without rain or high winds.
Temperature & Dissolved Oxygen
Surface Temp (℃) Surface DO (mg/L)
21.7 7.94
Summary / 2026 Recommendations
The 2025 aquatic management program at Perera Pond was conducted successfully, with all surveys,
treatments, water quality sampling, and upland invasive species management completed at the
appropriate times. As documented throughout the season, the pond re mained in good condition overall,
and each site visit showed steady improvement in ecological stability. Filamentous algae, documented
during the May visit, was treated promptly and did not become a recurring issue. Dissolved oxygen
remained within accepta ble ranges throughout the season, aided by the fully functioning aeration system.
Nuisance densities of elodea and thin-leaf pondweed were controlled effectively during the July
treatment, and water clarity remained stable, with Secchi depths ranging from 1’4” during early-season
turbidity episodes to 4’3” later in the year. Upland invasive species including phragmites, purple
loosestrife, Asiatic bittersweet, Japanese knotweed, and multiflora rose were treated through foliar
applications and selective hand-wiping where necessary. By the September visit, the pond exhibited very
good overall condition, with the previous treatments having provided clear improvements in both aquatic
and upland vegetation.
Looking ahead to 2026, we recommend continuing the structured, monitoring -driven approach that has
proven effective for this small, ecologically sensitive pond. Because vegetation conditions shift rapidly in
shallow waterbodies and because upland invasives continue to re-emerge from adjacent seed sources,
regular monthly monitoring should remain the centerpiece of the program. Early -season surveys (May –
June) will again guide algaecide and herbicide decisions, particularly for filamentous algae and early -
growth elodea or pondweed. As in 2025, contact herbicides remain appropriate for managing nuisance
densities of these native species. If thin-leaf pondweed or elodea reach near-surface growth during 2026,
a follow-up spot-treatment should again be applied to preserve open-water habitat.
Upland invasive species management should continue to be incorporated into each visit, as the 2025
season demonstrated that Phragmites australis, Japanese knotweed, purple loosestrife, and bittersweet
can reappear even after successful control. Hand-wiping and selective foliar treatment remain the
preferred approaches, as they minimize non-target impacts while preventing reestablishment. Knotweed
in particular should remain a monitoring priority, as it was observed again during the September visit.
Water quality monitoring should continue during every site visit, with dissolved oxygen, water
temperature, and Secchi clarity used to track long -term trends and guide the timing of treatments. The
aeration system should continue to be inspected during eac h visit, as its consistent performance in 2025
was an important factor in maintaining acceptable DO levels, especially during warm -weather conditions.
Algae monitoring should also remain part of the program, as shifts in temperature and precipitation
patterns such as those documented in 2025 can quickly trigger new blooms in shallow systems.
Overall, the management program at Perera Pond remains stable and effective, and the results from 2025
show that the combined approach of monitoring, targeted treatment, and upland invasive management
continues to maintain healthy pond conditions. By continuing these strategies in 2026, the ecological
function, visual quality, and long -term health of Perera Pond will remain protected.
We greatly appreciate the opportunity to continue working with the Town of Yarmouth and the Perera
Pond property owners. We look forward to supporting the ongoing health of Perera Pond in 2026 and
beyond. Should you have any questions about this report or future management strategies, please do not
hesitate to reach out.
Sincerely,
James Lacasse
Branch Manager
Senior Environmental Scientist
c: 774-276-6098
o: 888-4WETLAN(D)
james@waterandwetland.com
www.waterandwetland.com