State of the Bay



Download Full Text (18.1 MB)

Download 2015 State of the Bay Summary Flyer (776 KB)

Download Indicator: Bay Water Quality (1.9 MB)

Download Indicator: Climate Change (2.2 MB)

Download Indicator: Combined Sewer Overflows (1.7 MB)

Download Indicator: Conserved Lands (3.2 MB)

Download Indicator: Education and Stewardship (596 KB)

Download Indicator: Eelgrass Beds (1.5 MB)

Download Indicator: Impervious Surfaces (3.0 MB)

Download Indicator: Inland Water Quality (4.4 MB)

Download Indicator: Invasive Species (1.9 MB)

Download Indicator: Population and Land Cover (1.3 MB)

Download Indicator: Toxics (2.1 MB)

Download Indicator: Status of Shellfish Beds (2.1 MB)

Download Indicator: Stormwater (2.0 MB)

Download Indicator: Stream Connectivity (5.7 MB)

Download Indicator: Swimming Beaches (1.1 MB)

Download Indicator: Water Birds (1.2 MB)

Download 2015 State of the Bay Bibliography (134 KB)


The Casco Bay Estuary Partnership helps track and report on changing conditions within the Bay and its watershed. Every five years, in its State of the Bay report, the Partnership portrays how Casco Bay is faring—what trends are evident, what progress is visible, and what new challenges are emerging. By tracking indicators at regular intervals over decades, the Partnership helps identify the collective work needed to sustain the region.

State of the Bay 2015, summarized here and detailed online at, reveals a complex array of factors shaping the ecology and economy of the Casco Bay region. There’s a mix of encouraging news, interspersed with unsettling trends. The warming climate represents a vast and unpredictable driver of regional change—with hotter ocean and air temperatures, more frequent and extreme precipitation, and rising seas (already evident in flooding at extreme high tides).

Indicators used in the past (and included in the 2015 report) do not fully account for the dynamic interplay of forces currently at work on Casco Bay. Future reports will include new indicators to help gauge the pace and impacts of far reaching change.

Publication Date



water quality, toxics, habitat, eelgrass, climate change, CBEP


This document has been funded by the US Environmental Protection Agency under Cooperative Agreements #CE96185501 and #CE96190301 with the University of Southern Maine.

Recommended Citation:

Casco Bay Estuary Partnership. 2015. State of the Bay 2015 Report. Portland, Maine. Cover map of Casco Bay created by MollyMaps for the Envisioning Change Project ( Design: Waterview Consulting • GIS Maps: Center for Community GIS


Casco Bay, State of the Bay


Casco Bay, Casco Bay watershed

2015 State of the Bay Report



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