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What are the biggest challenges for the Bay?

Overall, Casco Bay is a healthy and productive system, but our coastal waters face a myriad of threats, including nitrogen pollution, ocean and coastal acidification, climate chaos, and stormwater pollution. As these challenges grow, government resources to tackle these threats continue to decline. More and more work and responsibilities are falling to local organizations such as ours.

What are the biggest threats to the Bay today?

In short, excess nitrogen, ocean and coastal acidification, stormwater pollution, and a lack of government resources to tackle these issues. As local, state, and federal governments’ budgets shrink, we are mobilizing more volunteers than ever to monitor water quality and help clean up our shorelines. As nitrogen pollution and acidification are changing the chemistry of the Bay, we are investigating innovative and collaborative ways to address these issues. As we focus our resources on protecting the health of Casco Bay, we are also continuing to build a resilient organization.

Climate change — Rising sea level, warming water temperature, and ocean acidity all impact our coastal waters. The resulting changes in weather patterns, storm surges, and coastal flooding are impacting our shorelines and Bay. Species shifts, infectious diseases, and invasive predators impact our ocean food web. Changes to our marine resources threaten the harvesting of traditional fisheries and innovations in aquaculture.

Nitrogen and coastal acidification — Nitrogen pollution from land is changing the chemistry of our Bay and putting stress on the health of our marine resources. Nitrogen is necessary for plant growth, but too much can trigger a population explosion of phytoplankton and green seaweeds. The “rise of slime” caused by nitrogen pollution results in mudflats smothered by mats of bright green algae, clam flats closed to harvesters by red tides, and murky waters choking out eelgrass beds.

Oil spills — As a major oil tanker port with a history of a only few major oil spills, we all need to  work to prevent spills and prepare to respond rapidly in the event of a spill.

Dredging — Deepening shipping channels and dredging our working waterfront must be managed to remove polluted sediments that can harm marine life.

Plastic pollution — Plastics are showing up in Casco Bay, from single-use shopping bags to nearly invisible microfibers. These plastics are swept into the ocean from land and off boats. 

We work on all these issues and so much more. We collect data on the health of the Bay and use this science to inform our advocacy and education. You can learn more about all of our areas of work here

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Cover photo: Photograph by Kevin Morris

Read more about the health of Casco Bay:

Testimony in Support of LD 1572: Resolve, To Analyze the Impact of Sea Level Rise

May 7, 2021

May 7, 2021 Senator Stacy Brenner Representative Ralph Tucker Environment and Natural Resources Committee ENR [at] legislature [dot] maine [dot] gov Re: Friends of Casco Bay Testimony in Support of LD 1572: Resolve, To Analyze the Impact of Sea Level Rise Dear Senator Brenner, Representative Tucker, and Esteemed Members of… Read more

Your Voice is Needed! Rising seas in Casco Bay

May 3, 2021

Casco Bay needs your voice! A crucial bill is making its way through the Maine Legislature: “LD 1572 Resolve, To Analyze the Impact of Sea Level Rise.” We hope you will lend your voice in support of this bill. This bill will require state agencies to incorporate sea level rise… Read more

Implementing Maine’s climate plan helps Casco Bay

April 28, 2021

Climate change threatens the health of Casco Bay. In March, more than 335 Friends of the Bay joined us for Sea Level Rise, Storms, and Surge Oh My! and told us the impacts of rising seas and stronger storms are a top concern. We agree. With climate change being such a large issue, to… Read more

Water Reporter Post of the Month: Sally Carlisle

April 22, 2021

Growing-up sailing the waters of Penobscot Bay with her dad, Water Reporter Sally Carlisle fell in love with the coast of Maine at a young age. Last fall, when Sally joined our community of Water Reporters, she began to notice something new about her life-long home. “Through all the years… Read more

Good news for Casco Bay!

April 16, 2021

We have great news to share: we reached the $1.5 million goal for our Climate Change and Casco Bay Fund for Technology, Monitoring, and Community Engagement! We launched the Fund to be used over the next decade to establish and maintain three oceanographic Continuous Monitoring Stations to collect data on… Read more

Celebrating Data From Our New Continuous Monitoring Stations — A Casco Bay Matters Event

April 15, 2021

We are hosting an online event to share data from all three of our Continuous Monitoring Stations and to celebrate the ways the Climate Change and Casco Bay Fund will enhance our efforts to improve and protect the health of the Bay for years to come. On Wednesday, June 16,… Read more