Casco Bay Monitoring Plan

Investigate Our


The Casco Bay Monitoring Plan provides a coordinated framework for the monitoring of Casco Bay and its watershed. The framework leverages existing data collection programs, identifies emerging information needs, and highlights data gaps. The Plan was first written in 1996 and was updated in 2004. 

A revision of the Monitoring Plan was completed by CBEP and the Casco Bay Monitoring Network in 2020. The Network is an informal community of individuals, organizations, and agencies involved with monitoring conditions in Casco Bay. It meets on a roughly semi-annual schedule to discuss recent observations, changes in monitoring plans and practices, and emerging monitoring needs.

The 2020 Casco Bay Monitoring Plan contains a catalog of 34 monitoring programs in Casco Bay, an extensive compendium of reports on monitoring efforts, conceptual diagrams detailing Stressors-State-Responses that highlight inter-relationships and identify information gaps, as well as a rank-ordered list of recommendations.

The Monitoring Plan addresses four questions through its Priority Topics: Are anthropogenic nutrients making the Bay less healthy? Are coastal habitats of Casco Bay both healthy and abundant enough to support ecosystem processes and protect the vitality of the Bay? Is the food web of Casco Bay changing and does it support marine biodiversity, food production and key ecosystem services? How do humans derive material and cultural benefits from the Bay?”

Nutrients and Water Quality ​

Priority 1

Nutrients and Water Quality

Track changes in nutrients and related water quality issues in fresh water and in the Bay.


Priority 2


Gauge the health and extent of priority habitats, including salt marshes, tidal flats, eelgrass beds, and connected waterways for migratory fish.

Food Web ​

Priority 3

Food Web

Monitor how the Casco Bay ecosystem links primary producers like phytoplankton and marine algae to fish and wildlife, charismatic species, and marine harvests.

Human Benefits​

Priority 4

Human Benefits

Understand how the Bay provides benefits to the people living along its shores and in its watershed and especially how coastal communities and economies depend on and connect to the Bay.