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Warming Waters Are Hot Topic

As the purple line for 2020 shows, temperatures measured at our Continuous Monitoring Station in Yarmouth, Maine, are setting records. Our staff, board, and volunteers are using data from the station in conversations with community members and decision makers to explore what we need to do to address and adapt to changes that are happening.


Day after day, we watched temperature records being set. This year has been hotter than usual. Out of the first 243 days of this year, January through August, 2020,  132 days exhibited a daily average temperature higher than established for that day in any of the prior four years, 2016 – 2019.

“While warm water temperatures may have been great for swimming in the Bay,” says Staff Scientist Mike Doan, “there are significant downsides to warming water. Less oxygen, more invasive species, changes in the ocean food web, and the growth of nuisance and harmful algal blooms are all associated with warming temperatures.”

In addition to hourly data collected at the station, Friends of Casco Bay’s staff monitor another 22 sites around the Bay as part of our seasonal spot-checks. Those sites, too, have been extremely warm. Our offshore site in Broad Sound saw temperatures near 22°C [almost 72°F], and the upper New Meadows River had temperatures over 25°C [nearly 80°F].

Other researchers have noted similarly high temperatures offshore in the Gulf of Maine this year. In August, NOAA satellites measured an average sea surface temperature of 68.93°F, nearly reaching the record set in 2012.

These data are critical as we continue our advocacy work with the Maine Climate Council at the state level and Portland and South Portland’s One Climate Future initiative at the local level, to address and mitigate the impacts of looming changes.

“What we have been seeing this year reaffirms for me the urgency of our collective work to document change, address the root causes of climate change, and prepare for its consequences at community, regional, state, and national levels,” says Casco Baykeeper Ivy Frignoca.

What Casco Bay is telling us

We had a lively and informative What Casco Bay is telling us: a Casco Bay Matters Event as more than 100 Friends joined us for the conversation. Here is a video of the event, for those of you who were not able to attend live or would like to relisten.

If you don’t have time to watch the entire event, here are some key moments that you may want to check out:

In this 3½ minute clip, Casco Baykeeper Ivy Frignoca shares her observations on what the Bay was like during this very strange year.

Staff Scientist Mike Doan shares temperature data from our Continuous Monitoring Station (2½ minutes).

Mike explains how we can get a sense of the productivity of the base of the food chain and offers his thoughts as to why our waters have been so clear this season (3 minutes).

Ivy thanks our volunteer Water Reporters for the many ways they have helped us keep watch on the health of the Bay (2½ minutes).

Ivy reflects on what we must do to confront the impacts of climate change on the Bay (2 ½ minutes).

Last but not least, Cathy, Ivy, and Mike explain how our Climate Change and Casco Bay Fund is a game-changer for our work (4 minutes). [We are delighted that we have raised 94% of our $1.5 million goal for the Fund, with the help of many of you. If you have not yet made a contribution to the Fund, help us past the finish line!]

Water Reporter Post of the Month

With 200 square miles of water and 578 miles of shoreline, Casco Bay is large and ecologically diverse. A changing climate, rising seas, and other threats to the health of our waters can have extremely local impacts, affecting coves, embayments, and islands each in different ways. We depend on volunteers from every community around the Bay to help us track changes they are seeing through our Water Reporter project.

Lindsey Mills of News Center Maine joined Casco Baykeeper Ivy Frignoca in the field to get a better understanding of this work. See that coverage here.

The story features the Merepoint Boat Launch in Brunswick. Our Water Reporter post of the month shows this same location.

This post, made by volunteer Dan Emery, is just one of the more than 110 observations he has shared using the Water Reporter app on his smartphone.

Dan has been helping us track the presence or absence of nuisance algal blooms around the Bay. These observations are helpful because blooms can be an indicator of nitrogen pollution. You can see that by mid-September Dan reported no algae at the boat launch.

Like many of our volunteers, Dan uses our Water Reporter project as a good excuse to explore many of the Bay’s nooks and crannies. He often bikes to locations along the Bay, making Water Reporter posts as he travels.

Dan volunteers his time, supports us through yearly membership contributions, and is a donor to our Climate Change and Casco Bay Fund and our Anchor Society. He is concerned about climate change and appreciates being able to take part in work that helps us understand how the Bay is being impacted. “I like Friends of Casco Bay because it gathers significant data relevant to climate issues, works pragmatically to affect policy and enforcement, provides clear and helpful educational materials, and engages members in its activities. Seeing the effects of climate change reinforced to me the value of giving a bequest to Friends of Casco Bay.”

We thank Dan for all the ways he is a good Friend of Casco Bay!

We appreciate Dan’s pledge and bequest to our Climate Change and Casco Bay Fund. If you would like to learn more about the Fund, you can do so here.

And, if you want to volunteer like Dan does, you can sign up here.

Join us for What is Casco Bay telling us?

This year has been unprecedented. Casco Bay is exhibiting changing conditions that may impact our community, marine heritage, and our economy in years to come.

Join Executive Director Cathy Ramsdell, Casco Baykeeper Ivy Frignoca, and Staff Scientist Mike Doan for a conversation about what we have been seeing out on the Bay this year, what our data are telling us, and what we, as a community and a state, need to do to address some of the impacts of climate change on the Bay.

On Wednesday, October 21, grab your lunch, log on to Zoom, and join the conversation.

You must register to join this event. We would love you to join us.

Register Now

What: What Casco Bay Is Telling Us: A Casco Bay Matters Event

When: Wednesday, October 21, 12:15 p.m. to 1 p.m.

This event will take place via Zoom. We will send you instructions for joining the event after you register.

What warming waters could mean for Casco Bay


This year has been one of the warmest on record. Why is that bad for the health of Casco Bay? Check out this short video as Staff Scientist Mike Doan takes a quick dive into our Continuous Monitoring Station’s data to share one of the biggest reasons we should be concerned about warming waters.

As always, you can always find our most recent Continuous Monitoring Station data on our website.

In case you missed them, here are the first three videos of Mike’s Field Notes:


Keeping up with the Casco Baykeeper

For Casco Baykeeper Ivy Frignoca, the summer has been full of moments of concern and moments of magic.

How was your summer?

Summer means being on the Bay! Staff Scientist Mike Doan and I continued to collect our seasonal data on the health of Casco Bay by land and sea. As we collected water quality data, we had the opportunity to speak with people who rely on the Bay for their livelihoods and deepened our conversations about what we were seeing and how to use our data to shape our advocacy work.

How did the pandemic affect your Baykeeping work this summer?

We kept up with water quality monitoring by limiting crew on our Baykeeper boat, R/V Joseph E. Payne, to just two of us at any one time. We continued to collect hourly data from our Continuous Monitoring Station. We kept up with all water quality monitoring, including responding to the unexpected.

What changed and what we really missed was inviting others out on the boat with us. We love using the boat as our summer office, a way to gather people who can work together to find solutions to problems that impair the health of the Bay. It makes a big difference to view issues from the water and have people aboard with expertise and authority to address problems. We couldn’t do that this year.

What was the most concerning issue you saw this summer?

What stands out was a day in mid-July when we saw a large area of brownish water extending from the mouth of the Royal River. Mike and I thought it might be a phytoplankton bloom. But when we put our sonde in the water, it measured low salinity levels that were startling, extending out almost to Moshier Island. We had captured a stormwater plume from a recent major rainstorm.

What also stands out was how uniformly high water temperatures remained this summer. Broad Cove saw temperatures near 20°C [70°F] and the upper New Meadows River had temperatures between 25-26.5°C [nearly 80°F].

What we saw this summer reaffirmed for me the urgency of our collective work to document change, reduce the causes of climate change, and prepare for its consequences at community, regional, state and national levels.

How about some of your favorite moments of the summer?

There are always moments of astounding beauty on the Bay. Every day on Casco Bay is magical. Watching terns feeding, bald eagles soaring above the boat, leaping sturgeons in a school of bait fish, or the sunlight reflecting like a mirror on the water are moments of magic that underlie why we work to protect this amazing place.

I really enjoyed becoming more deeply connected to our volunteer Water Reporters. Their posts track important issues and give us a great view of what is happening around the Bay. Working with Community Engagement Coordinator Sarah Lyman, I spent some socially-distanced time with Water Reporters, following up with them as they tracked algae blooms, marsh conditions, reported pollution, and posted about other changes they were seeing in the Bay. It’s awesome knowing that there is a whole team of people in the community helping with our Baykeeping work.

How rainstorms affect the Bay

Today’s rain reminds us that heavy rainstorms can deliver a significant insult to the health of Casco Bay.

Rainwater runoff resulting from intense storms flows into the Bay, bringing with it a host of pollutants including nitrogen, pesticides, oil, and heavy metals. If rainfall is heavy enough, the large dose of freshwater can temporarily lower the salinity, or saltiness, of the Bay.

This year we experienced a long stretch of dry weather through May and into June, which was followed by almost three inches of rain in just two days in late June. This combination created conditions that brought a large amount of freshwater into the Bay through both runoff and increased river flow. The river flow increase can be seen in the United States Geological Survey river gauge data from the Royal River. The Royal empties into Casco Bay near our Continuous Monitoring Station.

The graph above compares the flow of water in the Royal to the salinity at our Station in Yarmouth. The increase in fresh water following the storm causes a decrease in salinity at the station. It takes significant amounts of freshwater to dilute the water in the Bay. This suggests large amounts of stormwater runoff deliver pollutants to the Bay.

The increased river flow was still visible into mid-July. While out conducting our Seasonal Water Quality Monitoring on July 15, Staff Scientist Mike Doan and Casco Baykeeper Ivy Frignoca measured salinity values of 6.4 parts per thousand (ppt) at the mouth of the river where values are typically around 29.0 or 30.0 ppt. As they moved away from the river mouth and out toward deeper water, values were still lower than usual at 12 to 15 ppt.

In the period of time following the storm, we saw a dramatic increase in blooms of nuisance algae. This is potentially the result of increased nutrients in the stormwater runoff, as well as high water temperatures.

As Casco Bay continues to get warmer and we experience more frequent and intense rain storms because of climate change, we may see more pollutants and more nuisance algal blooms in the Bay.

This is one of the many reasons why Friends of Casco Bay launched the Climate Change and Casco Bay Fund, which will help us put two more Continuous Monitoring Stations in the Bay, one near Portland and one near Harpswell, and operate all three stations for ten years. The $1.5 million Climate Change and Casco Bay Fund will be used over the next decade to understand the ways in which our waters are changing, while we engage the community in assessing and adapting to climate change. You can read more about the Fund and our 10-year plan here.

What can you do about stormwater pollution?

  • Did you know that the fertilizers and pesticides you put on your lawn may end up in Casco Bay and contribute to these problems?
  • Keep pollutants from entering the Bay by reducing or eliminating the fertilizers and pesticides you apply to your lawn.
  • Become a Water Reporter. Our volunteer observing network tracks the spread of algal blooms around Casco Bay. We use that information to alert the State to changes in our coastal waters.
  • Make a donation to support the Climate Change and Casco Bay Fund.

Announcing the Climate Change and Casco Bay Fund

Casco Bay is changing and changing quickly. In the two minute video above, Executive Director Cathy Ramsdell announces the public phase of our Climate Change and Casco Bay Fund for Technology, Monitoring, and Community Engagement. We are creating a $1.5 million fund to be used over the next ten years to understand the ways in which our waters are threatened, while we engage the community in assessing and adapting to climate change.

The great news is that we are 86% of our way to our goal! You can help push us over the top!

We invite you to make a donation to our Climate Change and Casco Bay Fund.

Working together as a community to take care of this place may be our only hope to address climate
change; the cavalry is not coming to help. It is up to us.

If you would like to learn more about the Fund, you can read about our 10-year plan and make a donation here.

Casco Bay is heating up

Seem hotter than usual? Yes, indeed.

Our Continuous Monitoring Station has been collecting hourly data on the health of the Bay for more than four years.

Data from the station show that this summer has been the hottest one we have recorded since our “Cage of Science” has been in the water.

This graph compares water temperatures from 2016 to this month. The lavender-colored line represents the daily averages for this year.

Staff Scientist Mike Doan says “The data are concerning. This summer’s temperatures were on average the warmest we have seen at the station.”

You can find the most recent data for all the parameters we measure at our Cage of Science here.

In addition to collecting hourly data, for nearly 30 years, we have been spot-checking sites in the Bay. The temperature data from our three Sentinel Sites (see graph below for annual average, data collected May through October each year) show an upward trend as temperatures in Casco Bay have risen by 2.4° Fahrenheit [1.3° Celsius].

annual temperatures graph 2019

“Casco Bay is changing and changing quickly,” reports Executive Director Cathy Ramsdell. “That’s why we have launched the Climate Change and Casco Bay Fund, which will help us put two more Continuous Monitoring Stations in the water, one near Portland and one near Harpswell, and operate all three stations for ten years.”

The $1.5 million Climate Change and Casco Bay Fund will be used over the next decade to understand the ways in which our waters are changing, while we engage the community in assessing and adapting to climate change. Friends of Casco Bay has raised 87% of its goal for the Fund. You can read more about the Fund, our 10-year plan, and make a secure donation here.

Working with you to Keep Casco Bay Blue


We are excited to share a short film made by Knack Factory in honor of our 30th anniversary.

The Knack Factory team joined Friends of Casco Bay staff and volunteers on the water over the course of a week last fall to create a short film about our work.

Knack Factory is a Maine-based creative agency specializing in video production. They are a creative, highly-skilled community of story-tellers. There is no job too big or small (or crazy or weird or impossible) for them to tackle.