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How we work with you to keep Casco Bay blue

Casco Bay belongs to all of us. In 2019, we at Friends of Casco Bay are continuing our commitment to building a sense of shared ownership throughout our community, to help protect the health of this incredible resource. We see water as fundamental habitat and work to ensure that public policies keep the importance of the health of the Bay in mind.

Our community engagement opportunities provide a wide array of activities for citizens to assist us in our work and to advocate for the health of Casco Bay. For us, advocacy is about relationship building. We work to find common ground.

We pursue policies, laws, and limits based on sound science. Our advocacy efforts take place in many forums—from town halls to the halls of the State House to Washington, D.C. Sometimes, we protect the health of the Bay using education, convincing one homeowner or business at a time to change their practices. Other times, especially on regional or more complex problems, we advocate for the enforcement of existing laws and for the creation of new laws or ordinances. We look forward to working with you this year.

Spring Blooms in Casco Bay

What signs tell you that spring has arrived? Grass turning green? A robin in your yard? Ospreys returning to their nests?

What about huge blooms of phytoplankton in Casco Bay?

The chlorophyll fluorescence measurements in the graph above were recorded by our Continuous Monitoring Station, which has been in place for almost two years.

Chlorophyll fluorescence is a measure that provides an estimate of phytoplankton abundance. Chlorophyll is the green pigment in plants that traps the energy of the sun for photosynthesis.

The graph tells us that this year’s spring bloom of phytoplankton started around the same time as last year, but was bigger in magnitude this year than in 2017.

Why do we care about chlorophyll levels? Phytoplankton are the single-celled plants that make up the foundation of the ocean food web. Phytoplankton also provide half of all the oxygen we breath—so thank phytoplankton for every other breathe you take. You can read more about phytoplankton and chlorophyll in our recent post.

Photography by Kevin Morris

Every hour and every day, the Continuous Monitoring Station—a.k.a our “Cage of Science”—is building a more complete picture of the seasons beneath the Bay. Thanks to support from Casco Bay Estuary Partnership and generous donors, the Station collects measurements of temperature, salinity, pH, dissolved oxygen, carbon dioxide, and chlorophyll fluorescence year-round. Every other week, Research Associate Mike Doan cleans and calibrates the equipment, and downloads and graphs the data to track conditions in the Bay.

The looming question for the future— How is Casco Bay changing?

Photograph by Kevin Morris • Aerial support provided by LightHawk

We see water itself as fundamental habitat. When water quality deteriorates, eelgrass, plankton, clams, and other marine creatures suffer. Thanks to our 25-year data set on water quality in Casco Bay, we now have a better overall understanding of the health of the Bay. We understand when and which areas of the Bay are likely to exhibit challenged water quality conditions.

Armed with this baseline data, we can now begin to address the question How is the Bay changing?—thus, the establishment last year of our first automated Continuous Monitoring Station. We will also continue to monitor selected sites at the surface, to supplement the historical data set compiled by our Citizen Stewards Program. And, we will look more intensively, using surface-to-bottom transects, at those regions of the Bay which present challenged conditions. New data and observations may help us begin to understand how climate change, excess nitrogen, and the changing chemistry of Casco Bay may be impacting the ocean food web.

Our Nabbing Nitrogen event in 2016 signaled to us that there is a huge reservoir of goodwill from people who want to help protect the health of the Bay and are willing to do that in short bursts of data collection efforts. We foresee new volunteer opportunities in this type of data collection, as well as in expanding other community service projects, such as coastal clean-ups, storm drain stenciling efforts, and issue-education events to inspire Champions for the Bay.

Citizen Steward volunteers will continue to be key to our organization as they help us move into this next phase of work to improve and protect the environmental health of Casco Bay. Casco Bay belongs to all of us, and this Bay is fortunate to have so many Friends.

Cathy L Ramsdell, CPA, CGMA
Executive Director

Cathy Ramsdell Interview

After a rainstorm, millions of gallons of polluted stormwater pour into Casco Bay.

Stormwater: the Largest Source of Pollution into Casco Bay

Presumscot River Creates a Brown Bay
A wedge of polluted fresh water floats on top of Casco Bay.

MS4. Unless you are a civil engineer or a municipal public works director charged with dealing with discharge permits, you may not know that “MS4” stands for municipal separate storm sewer systems (called MS4 because “s” is repeated four times). An MS4 is a system of storm drains, pipes, or ditches that collect and carry stormwater, untreated, into our waterways (not to a sewage treatment facility).

To reduce stormwater pollution, the Clean Water Act requires larger cities and towns to develop an MS4 plan that includes six Minimum Control Measures: public education, public involvement and participation, illicit discharge
detection and elimination (finding and eliminating sources of contamination that improperly enter the pipes), construction measures designed to reduce stormwater pollution, post construction inspections to ensure compliance, and municipal pollution prevention practices.

MS4 permits for these plans must be renewed every five years. Casco Baykeeper Ivy Frignoca is participating in the stakeholder process initiated by Maine’s Department of Environmental Protection, as it drafts the next MS4 permit.
You may have noticed that storms are more intesne, and the pollutants that rainstorms are flushing into the Bay are increasing dramatically. After one heavy rainstorm, we found a wedge of polluted stormwater 18 feet deep floating on top of seawater in Portland Harbor. Ivy worries,“Imagine what it would be like for a fish trying to navigate through that toxic mix of oil and gas from city streets, pesticides, bacteria, and nitrogen pollution from sewage and fertilizers!”

Ivy says, “The goal is to improve water quality and reduce nitrogen inputs and other pollutants. Reviewing and commenting on drafts of the next MS4 permit gives us an opportunity to help reduce the impacts of the largest source of pollution into Casco Bay.”

Storm Drain Stenciling

Friends of Casco Bay Volunteers Take to the Streets—and the Beach

This past summer, volunteers undertook several community service projects to help keep Casco Bay clean. Thank you to TD Green Team, the Leadership Development Program at Windsor Mountain Summer Camp, IDEXX, and Yelp for cleaning up our coastline. Thank you to Bowdoin Women’s lacrosse team, RBC, and Mark Edwards and Jane Braun for stenciling storm drains!

Continuous Monitoring Station

Monitoring a Changing Casco Bay 365 Days a Year

Continuous Monitoring Station
When we haul up the Continuous Monitoring Station to download data and recalibrate the equipment, we also track marine creatures that may have found a home on our “cage of science.”

Covered with sea squirts, sea stars, and other marine hitchhikers, the newest member of our monitoring team looks like an abandoned lobster trap. It may be homely, but we are pretty impressed with what it does, collecting water quality data hourly, 24 hours a day, 365 days a year. It is our Continuous Monitoring Station, which will help us answer the question “How are our coastal waters changing over time?” Research Associate Mike Doan calls it “the cage of science.”

It has been just over a year since we placed a carbon dioxide sensor and a data sonde—an electronic device that records temperature, pH, and other characteristics of water quality—inside this modified lobster trap and moored it in healthy waters near the center of Casco Bay off Cousins Island in Yarmouth.

After one full year, we have over 8,760 hours of data on oxygen levels, carbon dioxide, pH (the level of acidity of the water), salinity, temperature, chlorophyll fluorescence (estimated phytoplankton abundance), water clarity, and water depth.

Thanks to our 26-year data set on water quality in Casco Bay, we understand when and which areas of the Bay are likely to exhibit challenged water quality conditions that require further study. Armed with this baseline data, we can now consider how to address the question, How is the Bay changing?

The steady flow of data from the Station already is helping us detect and document how climate change and emerging coastal stressors may be affecting the Bay. Hourly data helps us identify daily, seasonal,
and annual trends to better understand the extent to which ocean acidification may be impacting the water chemistry of Casco Bay. In future years, we hope to deploy two more “cages of science,” one in challenged waters in Portland Harbor and one near Harpswell to help detect the influence the Kennebec River has on Eastern Casco Bay.

What is a data sonde?
A data sonde, such as the one being used by Research Associate Mike Doan, is an oceanographic
monitoring instrument that takes multiple measurements of water quality simultaneously. In
addition to being used as part of our Continuous Monitoring Station, data sondes are used by
staff scientists in other water quality monitoring efforts from shore and by boat. The data is
downloaded to a computer and analyzed to provide a long-term picture of water quality over
time. We thank Casco Bay Estuary Partnership and our generous members for helping fund
our Continuous Monitoring Station’s first year.


Casco Bay: Then and Now

THEN—Sewage, Sappi, and oil spills

Early on in our history, Friends of Casco Bay confronted the fact that millions of gallons of raw sewage emptied into Casco Bay each year from overflowing sewer pipes. Sewage from boats was also a concern, leading us to establish a marine toilet pumpout service for recreational boats. Our advocacy for regulations to prevent cruise ships from discharging polluted water right at the dock helped make Casco Bay one of the most protected bays in the nation from vessel sewage and other wastewater.

We battled pollution on many fronts, all while building an organization based on scientific credibility and a “work with” approach. By pushing to enforce existing environmental regulations, we helped to eliminate the biggest source of pollution to Casco Bay—pulp wastes from the Westbrook paper mill. This wastewater sucked the oxygen from the Presumpscot River and delivered toxic water to Casco Bay.

As one of the busiest oil delivery ports on the East Coast, Portland needed to prepare for the very real possibility of an oil spill. Friends of Casco Bay lobbied for more training and cleanup equipment. This preparation enabled responders to recover 78% of the 180,000 gallons of oil spilled when the Julie N tanker hit the Casco Bay Bridge in 1996.

To learn about pollution in the past, click here.

NOW—Nitrogen pollution, ocean acidification, and sinking oil—threats we didn’t even think about a generation ago

Today, Casco Bay faces new challenges. Our research shows that parts of Casco Bay are acidic enough to dissolve juvenile clams. The cause? Carbon dioxide from emissions from tailpipes and smokestacks and nitrogen pollution from sewage discharges, fertilizers, and stormwater runoff. Excess nitrogen triggers algae blooms that result in more carbon dioxide and less oxygen in seawater.

We are again warning that Portland Harbor needs to be better prepared for an oil spill, including spills of heavy crude oils, which may sink to the bottom of the Bay, making our current cleanup tools ineffective.

We often say, “Think local, act local”, a mantra that we find ourselves using more and more, as local communities become the change agents for environmental activism/progress to combat pollution and climate change. We help municipalities craft ordinances on pesticides, plastics, stormwater pollution, and other issues that later are adopted by neighboring cities and towns.

While our focus remains Casco Bay, we recognize that global climate change threatens every water body, and indeed, every individual on the planet. The impact of rising seas, warming water, and acidifying oceans is truly a game changer, creating environmental and social challenges faster than anyone anticipated.

Did you know…How many lighthouses are in Casco Bay?

Did you know…How many lighthouses are in Casco Bay?
All are in the southwest region of the Bay, which is not surprising, since this where ship traffic is concentrated. Draw them on a chart of Casco Bay.
1. “Bug Light,” South Portland, Portland Breakwater
2. Spring Point Ledge, South Portland, Southern Maine Community College campus
3. Ram Island Ledge
4. Portland Head Light
5. Two Lights, Cape Elizabeth
6. Halfway Rock Lighthouse, south of Baily Island
7. Echo Point Light, Great Diamond Island (a tiny lighthouse on the southwest tip of the island)
8. Little Mark Island, south of Bailey Island (this light is on a monument and is not officially a lighthouse)


So you think you know Casco Bay

So You Think You Know Casco Bay


1. What are the landward and seaward boundaries of Casco Bay?


_________________ _______________________

2. How many coastal or island communities border Casco Bay?



3. What is an estuary and why is it important?






4. What are some of the leading threats to the environmental health of Casco Bay?




5. Name two important marine residents of Casco Bay and describe why they are important.

______________________ ________________________________________


______________________ ________________________________________


6. Describe one action children and/or their families can take to protect Casco Bay.


ANSWERS: So You Think You Know Casco Bay

1 What are the landward and seaward boundaries of Casco Bay?
Cape Elizabeth (Two Lights), Cape Small (Phippsburg), Halfway Rock

2 How many coastal or island communities border Casco Bay? 14

3 What is an estuary and why is it important?
Where rivers and ocean meet; important as feeding, breeding, and nursery grounds for marine life and birds; protected, food-rich settlements for humans

4 What are some of the leading threats to the environmental health of Casco Bay?
Stormwater runoff, nitrogen pollution, sewage, coastal acidification

5 Name two important marine residents of Casco Bay and describe why you think they are important.
Lobsters most important fishery in Maine
Eelgrass nursery for many marine animals
Soft-shell clams 2rd most important fishery in Maine
Harbor seals iconic marine life
Mackerel, striped bass, bluefish popular among recreational fishermen
Pogies (menhaden) caught commercially for lobster bait

6 Describe one action your family can take to protect Casco Bay.
Reduce use of fertilizers and pesticides, don’t discard cigarette butts, pick up dog wastes, any other actions that reduce pollution that can run into the Bay


Field trip!
Go to Buoy Park, the small park next to the Casco Bay Lines terminal along Commercial Street in downtown Portland. You will find four panels that explain the history of Casco Bay. (If you can’t get there, read them here [http://www.cascobayestuary.org/resources/graphics-signs/)
Find three facts you did not know and create your own “So you think you know Casco Bay” to quiz your family and friends.


Ecology: What makes Casco Bay an estuary?

Estuaries are defined as “where the river meets the sea”

Estuaries form where river meets the sea and fresh water mixes with salt. Teeming with life, these places of salt marshes, eelgrass beds, mudflats, and tidal waters serve as nursery areas for oceangoing fish, migratory stopovers for shorebirds, and homes for an amazing diversity of shellfish, fish, mammals, horseshoe crabs, crabs, plankton, and many others sea creatures.

Casco Bay is saltier than most estuaries because the rivers that flow into Casco Bay are small and do not contribute much fresh water to the system.

Salinity variations in Casco Bay are less a result of changing tides, as in many estuaries, than the distance from freshwater inputs (rivers and rain runoff)


Find the rivers of Casco Bay

Look at a map of the towns that border Casco Bay, from Cape Elizabeth to Phippsburg. [link] Find the rivers that flow into Casco Bay (Fore River, Presumpscot River, Royal River, and Harraseeket River).

Lay a string along the twists and turns of each river from its source to the sea, and then straighten it out on a ruler to find the length. Which is longest?

Which one is closest to where you live?

Look at a chart of Casco Bay.

Here’s a trick question: Which river delivers the most freshwater to Casco Bay?

The river that delivers the most freshwater to Casco Bay isn’t even in Casco Bay; it’s the Kennebec River, which flows into the ocean between Phippsburg and Georgetown, just beyond Casco Bay. It carries water from several rivers, including the Kennebec, Cathance, and Androscoggin rivers. All are considerably longer than any rivers that flow into Casco Bay. This freshwater input curls around and into eastern Casco Bay.


Fresh to Salty

Find 3 sites on the chart: a river mouth, a nearshore site, and offshore:

  • Mouth of the Presumpscot River, Falmouth
  • Fort Gorges, which is just off the Presumpscot and Fore rivers
  • Ram Island Ledge at the entrance Portland Harbor (not far from Portland head Light)


Which one do you think is the saltiest? Which one is the least saltiest?


A river has zero salinity; Casco Bay’s average salinity ranges from 25 to 32 parts per thousand (ppt), and open ocean water has salinity of about 32-35 ppt. Thus, the average salinity of seawater is about 0.3%.


Another way to figure out which site is saltiest is to look out the actual data collected by Friends of Casco Bay.


How did we collect this information? Volunteers collected water samples along the shoreline between April and October; staff scientists sampled by boat year-round.


Average Surface Salinities at 3 Sites in Casco Bay, 2001-2005

Measured in parts per thousand (ppt)

Compare the average monthly salinity data for those three sites in Casco Bay.


Month                  Presumpscot River                          Ft. Gorges           Ram Island Ledge


January                                                                                                29.4 ppt                                32.0 ppt

February                                                                              31.0                                        32.1

March                                                                                   27.8                                        30.7

April                       1.3 ppt                                                  28.7                                        30.0

May                       2.6                                                          30.0                                        30.6

June                      1.3                                                          28.0                                        30.3

July                        2.4                                                          29.9                                        30.6

August                  2.3                                                          30.1                                        31.2

September         4.2                                                          30.5                                        31.4

October               3.1                                                          29.5                                        31.7

November                                                                          29.5                                        31.3

December                                                                           28.1                                        32.9


What’s left behind?

What factors affect the salinity in Casco Bay? (rivers, tides, rain, melting snow, evaporation, ocean currents).

Collect jars of water from a river, from just where the river meets the bay, and from the ocean. Put each sample into a separate aluminum pan and allow the water to evaporate over the next day or two. What is the residue left at the bottom of pan?  How do they differ?

After all the water has evaporated, mix up the pie plates and challenge others to figure out which is from the river (hint: no salt, maybe a little sand), the mouth of the estuary (some salt), and open ocean (most salt).

Caution: Don’t let anyone try to figure out which is saltiest by tasting the granules! Why not?


Books that trace the river to the sea

  • The Secret Bay by Kimberly Ridley and Rebekah Raye, Tilbury House, 2015
    The Secret Bay uses a variety of formats to explain the life of estuaries:  poetry, natural-history sidebars, and field guide
  • A Day in the Salt Marsh. by Kevin Kurtz, Sylvan Dell Publishing, 2007
    Hourly changes brought on by the tides


What is the value of estuaries?

Brainstorm a list of ways that an estuary is valuable for wildlife (including marine life, birds, and terrestrial animals). If you need ideas, check out the resources below: