Habitat Protection & Restoration

Casco Bay’s diverse ecosystems—including extensive eelgrass meadows, productive mudflats, rocky intertidal zones, and fringing salt marshes—play a vital role in supporting a wide range of fish and wildlife species. Beyond providing critical habitats, these areas offer essential benefits like flood absorption, nutrient removal, and resilience against climatic extremes.

The Bay is nourished by a network of small coastal streams and a few larger rivers, which supply fresh water, sediments, nutrients, and other materials. These waterways are crucial for diadromous fish—species that migrate between the bay and freshwater bodies—contributing nutrients and food sources to inland waters. The long-term health of Casco Bay relies on preserving these habitats and maintaining connectivity between aquatic environments, ensuring that species can migrate, adapt to climatic changes, and sustain their populations despite various stressors.

However, both historical and ongoing human activities have significantly degraded these ecosystems, with impacts varying across different habitats. Eelgrass beds are particularly vulnerable to excess nutrients and poor water clarity, while dammed rivers create pond-like conditions that disrupt natural river communities. Tidal flows into salt marshes have been obstructed or reduced by roads, railways, and dikes, depriving these marshes of vital sediment. Additionally, poorly maintained septic systems continue to contaminate shellfish beds, limiting shellfish harvesting opportunities.

Casco Bay Estuary Partnership (CBEP), working closely with partner organizations and local communities, allocates resources toward projects that result in the protection, restoration, and enhancement of aquatic habitats that sustain the Bay’s health. Focus areas include:

• Conserving significant coastal habitats and areas that protect water quality, such as river corridors, wetlands, and headwater forests. Through its Habitat Protection Fund CBEP offers technical assistance, grant writing support, small grants, and project coordination to local communities and partners for initiatives like tidal restoration (culvert replacement) or eelgrass transplants, all aimed at restoring or enhancing vital coastal habitats. These projects often have the dual benefit of increasing resilience for both human and ecological communities.
• Restoring aquatic habitat connectivity. Barriers like dams and undersized culverts along streams and rivers often fragment these waterways into isolated sections, disrupting natural processes that allow the flow of floodwaters, fish, aquatic organisms, sediments, and wood through the watershed and into the Bay. CBEP collaborates with partners to restore these crucial connections, especially where barriers block the migration of fish like river herring and shad.
• Piloting new methods of enhancing ecosystems.  CBEP is working with partners to explore the use of locally available material such as recycled shell and wood to stabilize eroding shorelines, improve water quality, and maintain ecological processes where land meets the Bay. In 2020, Maine Geological Survey led a collaborative project with CBEP and other partners to pilot the use of “living shorelines” at sites in Brunswick and Yarmouth.