Friends of Casco Bay Executive Director Cathy Ramsdell and Mike Doan, research associate, collect water samples in Portland Harbor. Doan, who has collected water-quality data for the past two decades, said, “We realized we didn’t have the frequency of data to really track change.” Photo courtesy of Friends of Casco Bay

Researchers for Friends of Casco Bay plan to add two round-the-clock water-quality monitoring stations to better track temperature, acidity and potential marine “stressors” in a busy corner of the fast-changing Gulf of Maine.

After roughly 30 years of manually collecting and testing water samples once a month, Friends of Casco Bay launched the nonprofit’s first “continuous monitoring station” near Cousins Island in Yarmouth in 2016.

The station has collected hourly data on water temperature, salinity, dissolved oxygen and other environmental conditions as the organization sought to build upon the “snapshot” of monthly data that was clearly showing changes in Casco Bay.

“It wasn’t enough to go out once a month. We needed to start documenting the changes we’ve been seeing,” said Mike Doan, the research associate at Friends of Casco Bay who has collected much of that data for the past two decades. “We realized we didn’t have the frequency of data to really track change. If you want to get serious about documenting change, you need frequent data.”

With three years of hourly data now on hand, Friends of Casco Bay hopes to deploy similar continuous monitoring stations in Portland Harbor and in the New Meadows area near Harpswell. Those stations could shed light on local differences in a heavily trafficked area (Portland) as well as an area that has become a prime destination for aquaculture operators (New Meadows).

“We are really looking 30 years out,” Doan said. “And hopefully we’ll have those two new stations … and then we’ll be off and running.”


Friends of Casco Bay is among more than a dozen nonprofits, universities and government agencies that monitor different conditions in a bay that stretches from Cape Elizabeth to Phippsburg. Some track fish and invertebrate populations while others monitor nutrient levels, biotoxins or the phenomenon known as “ocean acidification.”

The Casco Bay Estuary Partnership then works with and between those dozen-plus organizations to collect that data and make it available to the other groups or the public. Some of that information is then posted online through the Casco Bay Monitoring Network.

Taken together, the various monitoring programs provide a more holistic view of conditions in Casco Bay at a time when the broader Gulf of Maine is undergoing dramatic shifts as a result of the changing climate.

Zachary Whitener, a research associate who helps coordinate the Gulf of Maine Research Institute’s Casco Bay Aquatic System Survey, said the various monitoring programs complement each other as different organizations zero in on different areas.

The Portland-based Gulf of Maine Research Institute, for instance, is perhaps best known for its research on fish species and fisheries. So the institute’s Casco Bay Aquatic System Survey (CBASS, for short) has focused on documenting codfish populations in the bay, potential nonpoint pollution sources through sampling of mussels in specific areas and monitoring of species in near-shore areas.

In the latter example, Whitener and other GMRI staff or interns use 150-foot seine nets to “see who’s home” every few weeks at about a dozen area beaches. That research helps them better understand both the seasonal changes in the marine environment – such as when tomcod and juvenile pollock move out and juvenile herring and alewives move in – but also the gradual, year-over-year changes.


Equally important, Whitener said, is it gives him and other scientists a chance to engage the public in conversations about the ecology and health of Casco Bay as they see researchers documenting the fish, crabs and other critters they find.

“What’s really important about these monitoring projects that everyone is doing around Casco Bay is, not only is it valuable science, but it is a valuable way for us to interact with the public,” Whitener said. “It’s a great opportunity with this monitoring work to show the public the work that we are doing and why it is important.”

Other groups or organizations monitoring conditions in Casco Bay include the University of Maine, Bowdoin College, Southern Maine Community College, the University of New Hampshire, the Island Institute, Casco Bay Estuary Partnership, Maine Coastal Program, Maine Healthy Beaches, the U.S. Environmental Protection Agency, the Maine Department of Marine Resources and the Maine Department of Environmental Protection.

Friends of Casco Bay is in the initial stages of a fundraising campaign to raise money for the next two continuous monitoring stations, each of which can cost upward of $70,000 plus maintenance.

Each station is actually a modern lobster trap – or “cage of science,” as Doan calls it – that has been retrofitted to safely and securely house a “data sonde,” a device that records various water conditions simultaneously. A separate instrument then measures carbon dioxide, which is a key concern in Maine and elsewhere as climate change causes more ocean acidification.

As humans pump more carbon dioxide into the atmosphere by burning fossil fuels, the world’s oceans absorb a greater share of the gas. That changes the ocean chemistry, leading to more acidic waters. And higher acidity can make it more difficult for shellfish – including lobsters and clams – to form their shells.

The three years of data collected by Friends of Casco Bay through their continuous monitoring station isn’t enough to make any decisive conclusions on changes. But the hourly data is allowing Friends of Casco Bay to more closely document the local trends as the wider Gulf of Maine heats up earlier in the year and stays warm longer.

The two additional stations will enhance that understanding of how conditions in other areas of Casco Bay are changing.

“Our goal is to track long-term change,” Doan said.

Comments are no longer available on this story