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

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