35th Anniversary logo for Friends of Casco Bay

Questions Lead to More Questions

Have you ever heard grown-ups growl at persistently curious children, “You ask too many questions!”?

Never say that to scientists. As soon as they start to research one question, scientists discover more questions along the way — lots more.

Since 1993, Friends of Casco Bay has trained more than 650 citizen scientists to monitor the health of Casco Bay. The data these volunteers collect twice a day on ten selected Saturdays between April and October comprises the basis of the Casco Bay Health Index. The Health Index provides a reliable, easy-to-understand indicator of the Bay’s overall water quality.

Our scientists use the Health Index to begin to address these questions, and more:

  • Which sites, based on below-average water quality, may require a closer look?
  • What is the relative condition of sites across a region?
  • How does each site compare to the other?
  • Are there parts of the Bay where we should be able to expect better or worse conditions?


At our Volunteer Appreciation Celebration, Research Associate Mike Doan reported on his analysis of the last five years of water quality data in order to answer another question: How has each site changed over time?


Mike said that the Health Index will be updated every year, incorporating the most recent data collected by our citizen scientists. This way, we can track which sites are improving, which are staying the same, and which are being degraded. “Wouldn’t it be great, moving forward, for us to focus more attention on those regions that consistently score lower?” Mike mused.

ike shared a graph of Health Index Score over time for Custom House Wharf in Portland, which showed the greatest change — for the worse. The yellow bars indicate a Health index score of “fair” and the red bars indicate a health index score of “poor”.