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Category: Volunteer Citizen Stewards Initiatives

Back Cove August 2nd, 2017

Our “Slime Watchers” Are Keeping an Eye on the Bay

Back Cove August 2nd, 2017
Friends of Casco Bay volunteer Deb Dawson took this algal bloom photo over Portland’s Back Cove this summer to document how much the green slime had spread.

If you have ever thought about buying a drone but could not figure out what to use it for, take a lesson from Deb Dawson, a professional photographer and one of our volunteer water quality monitors. This past summer, Deb took her talents to even greater heights—right over Back Cove in Portland with her new drone outfitted with a video camera.

Executive Director Cathy Ramsdell, who regularly walks Baxter Boulevard, had reported seeing green algae growth spreading across Back Cove. She says, “We know that nitrogen fertilizes green plants in the ocean just as it does on land. It would be great if we could determine what is causing this bloom – excess fertilizer? – stormwater runoff? – sewage discharges? – a lack of predators? – car and factory emissions? – or all of the above!”

Before launching her drone, Deb checked with the Portland Jetport to make sure the route she had scouted out would not interfere with the traffic pattern of landing and departing planes.

Deb’s images confirmed what Cathy had feared: the Cove was quickly becoming carpeted in green slime. An email alert went out to Friends of Casco Bay members and the news media.

Other “green slime” reports have come in from other parts of Casco Bay. Report excess green slime by emailing slimewatchers@cascobay. org. Take a photo and tell us the location, with coordinates and landmarks, if you can.

Nabbing Nitrogen results

Nabbing Nitrogen Flash Mob: What We Learned

Nabbing Nitrogen results
Nitrogen levels were high at every place we sampled. The highest levels of
nitrogen were found closer to land, in tidal creeks and near combined sewer
overflows. Lower nitrogen levels were found further from shore.

On Sunday morning, July 10th, 2016, at precisely 10:10 a.m., 97 people knelt down along the edge of Portland Harbor and scooped up small vials of water from Casco Bay. They were not praising Poseidon—they were Nabbing Nitrogen.

A recent heavy rain had flushed a surge of stormwater into the Fore River, so we were not surprised that
the analysis of their water samples found elevated levels of nitrogen. The most important takeaway of the event, though, was that there is an amazing Casco Bay community of volunteers ready and willing to get involved when we send out a call to action!

Interactive Casco Bay Health Index

Interactive Health Index

Friends of Casco Bay has developed the Casco Bay Health Index, an easy-to-interpret, visual guide to the health of the Bay. The Index allows us to integrate data from selected water quality parameters into a single value to compare and rank each site as Good, Fair, or Poor.

 

Now we have our new Interactive Health Index!

By clicking here, or the image below, you can see and interact with the Health Index. The Interactive Health Index will open in a new tab. By clicking on the dots you can see more about each sampling location.

Interactive Casco Bay Health Index

Overall, the water quality in Casco Bay is good, but there are instances when low oxygen, low pH, and murky waters are cause for concern. The 2016 Health Index reveals that over 31% of the sites are considered Poor, but more than 36% of the sites meet the Good standard.

The relative rankings were calculated by analyzing dissolved oxygen, water clarity, and pH data from shoreside sites that our volunteer Citizen Stewards monitored from 2012 to 2016. The values we chose to use were the 90th percentile of the dissolved oxygen percent saturation, the mean of the Secchi depth, and the mean of the diurnal differences in pH.

Commonly Asked Questions about the Casco Bay Health Index

 

What is the Casco Bay Health Index?

The Casco Bay Health Index was developed to provide a reliable, uncomplicated composite indicator of the Bay’s health, while also illustrating relative levels of eutrophication. The Index allows the scientifically-sound data collected through Friends of Casco Bay’s Water Quality Monitoring Program to be presented in a format that is easy to understand and to update.

 

What is the goal of the Index?

The goal of the Health Index is to present water quality information in an easy-to-understand visual format by condensing a large amount of existing data into a single score for each monitoring site. By summarizing a suite of environmental parameters into one score for each water quality monitoring site, each site can be ranked relative to one another, and trends—if there are any—can be more readily identified. This product, while quantitative in nature, should be considered a qualitative place to begin to determine environmental health. The sites are assigned colors—red, yellow or green, and are mapped to indicate the health of the waters around Casco Bay. Then we can ask: Which sites, based on the selected criteria, require a closer look? What is the relative condition of sites across a region? Are these conditions improving or degrading over time?

 

Where do the data for the Health Index come from?

The data used for the Health Index come from Friends of Casco Bay’s Citizen Stewards Water Quality Monitoring Program. Volunteers are well-trained using EPA-approved protocols developed by Friends of Casco Bay. They monitor specific sites and collect the data twice a day on 10 appointed Saturdays, between April and October. The Index incorporates the data for a 10-year span of time and can be updated annually by adding the most recent year’s data and eliminating the oldest. We can also look at the Index in five year increments to compare changes over time.

 

Which of the existing water quality parameters are most appropriate to use in the Index?

Friends of Casco Bay currently monitors five physical and chemical water quality parameters through our Citizen Stewards Water Quality Monitoring Program: temperature, salinity, dissolved oxygen (DO), Secchi depth, and pH. Of these, three have been selected for use in the Health Index—DO, Secchi depth, and pH.

 

Dissolved oxygen (DO) DO is expressed as Percent Saturation in order to incorporate temperature and salinity. When water holds all the oxygen it can at a given temperature and salinity, it is said to be 100% saturated. At a given site during a given sampling event, temperature and salinity are measured, and DO is measured in milligrams per liter (mg/l) and then compared with the mg/l for 100% saturation in those conditions. We look at the distribution of the Percent Saturation data; we consider the lowest 10th percentile as the worse-case conditions for a particular site. That 10th percentile threshold, expressed as a Percent Saturation number, becomes a component of the Health Index for that site.

 

Simply averaging all the DO data for a site might obscure the full extent of any challenged conditions. For example, if a site is eutrophic, wherein nitrogen pollution levels have resulted in a huge algal bloom, there will be large swings in DO levels between the morning and the afternoon; simply looking at the mean would obscure these swings.

 

Secchi depth Secchi depth is a measure of water clarity. The Index uses a mean of the data to characterize each site. Sites with more organic matter and sediments in the water will be murkier and will exhibit reduced clarity, resulting in shallower (lower) Secchi depth measurements.

 

pH pH is a measure of the acidity of the water. pH data exhibit tremendous variability—diurnal differences through the day and seasonal shifts through the year. The Water Quality Monitoring Program requires that measurements be collected at 7:00 a.m. and then again at 3:00 p.m. on each monitoring day. This allows for a look at the change in conditions over the course of a day. The pH at a site is influenced heavily by respiration and photosynthesis. Respiration by algae, both seaweeds and phytoplankton, adds carbon dioxide to the water, which lowers pH. Measurements collected in the early morning, at 7:00 a.m., reflect the conditions found after a night of respiration and no photosynthesis. Photosynthesis of course requires sunlight and removes carbon dioxide from the water, raising pH. By afternoon, at 3:00 p.m., pH measurements will reflect the result of photosynthesis. The change between the morning and afternoon measurements, termed the diurnal swing, can be indicative of the magnitude of respiration and photosynthesis, and, indirectly, the amount of algae in the water. Since an excessive bloom of algae is one symptom of nitrogen pollution, a large diurnal swing in pH can serve as an indicator of excess nitrogen. A small change in pH is expected in a healthy, productive coastal system, but a relatively large swing can indicate a challenged site. We calculate the difference between the morning and afternoon readings, the diurnal swing, then amass that dataset to calculate the mean for the Health Index for that site.

 

What ranges are most appropriate for the component parameters?

For each of the three components of the Health Index, we have defined ranges, between which we would expect to see worse-case and best-case conditions. These ranges have been defined by looking not only at data for Casco Bay, but also data from other regions, state and federal guidelines, and relevant scientific literature.

 

Parameter: 0 point value 100 point value
Percent Saturation of Dissolved Oxygen 65% 95%
Secchi Depth (meters) 0.2 m 3.0 m
pH (diurnal swing) 0.4 0.1

 

How is the Health Index score calculated?

Each of the components calculated for a given site is plotted along the scale for that parameter. We use a natural logarithm formula to determine where on the scale of 0 to 100 a particular component falls. For example, a site’s calculated 10th percentile threshold for the Percent Saturation parameter will fall between 65% and 95% at a specific point on the scale between 0 and 100. The same is done for the Secchi depth component and the diurnal swing in pH. Now we have three numbers which fall between 0 and 100. These are added together and divided by 3 to obtain the mean, which is the Health Index score for that site.

 

How are the final Health Index scores presented?

After each site has a Health Index score associated with it, it can be classified as Good, Fair, and Poor, determined by score thresholds. A score of 85 and above is considered “Good”, a score of 70 to 84 is “Fair”, and anything below 70 falls into the “Poor” category.

 

What is eutrophication?

Eutrophication occurs when too many nutrients (and occasionally other factors) fuel explosive plant growth. While nitrogen is an essential nutrient in marine systems, too much nitrogen can become a pollutant when it triggers excessive algal growth. This growth can result in low DO measurements, shallow Secchi depth readings, and wide variations in pH.

2016 Casco Bay Health Index

Casco Bay Health Index – Updated with 2016 data

2016 Casco Bay Health Index

 

Friends of Casco Bay has developed the Casco Bay Health Index, an easy-to-interpret, visual guide to the health of the Bay. The Index allows us to integrate data from selected water quality parameters into a single value to compare and rank each site as Good, Fair, or Poor.

Overall, the water quality in Casco Bay is good, but there are instances when low oxygen, low pH, and murky waters are cause for concern. The 2016 Health Index reveals that over 31% of the sites are considered Poor, but more than 36% of the sites meet the Good standard.

The relative rankings were calculated by analyzing dissolved oxygen, water clarity, and pH data from shoreside sites that our volunteer Citizen Stewards monitored from 2012 to 2016. The values we chose to use were the 90th percentile of the dissolved oxygen percent saturation, the mean of the Secchi depth, and the mean of the diurnal differences in pH.

Commonly Asked Questions about the Casco Bay Health Index

 

What is the Casco Bay Health Index?

The Casco Bay Health Index was developed to provide a reliable, uncomplicated composite indicator of the Bay’s health, while also illustrating relative levels of eutrophication. The Index allows the scientifically-sound data collected through Friends of Casco Bay’s Water Quality Monitoring Program to be presented in a format that is easy to understand and to update.

 

What is the goal of the Index?

The goal of the Health Index is to present water quality information in an easy-to-understand visual format by condensing a large amount of existing data into a single score for each monitoring site. By summarizing a suite of environmental parameters into one score for each water quality monitoring site, each site can be ranked relative to one another, and trends—if there are any—can be more readily identified. This product, while quantitative in nature, should be considered a qualitative place to begin to determine environmental health. The sites are assigned colors—red, yellow or green, and are mapped to indicate the health of the waters around Casco Bay. Then we can ask: Which sites, based on the selected criteria, require a closer look? What is the relative condition of sites across a region? Are these conditions improving or degrading over time?

 

Where do the data for the Health Index come from?

The data used for the Health Index come from Friends of Casco Bay’s Citizen Stewards Water Quality Monitoring Program. Volunteers are well-trained using EPA-approved protocols developed by Friends of Casco Bay. They monitor specific sites and collect the data twice a day on 10 appointed Saturdays, between April and October. The Index incorporates the data for a 10-year span of time and can be updated annually by adding the most recent year’s data and eliminating the oldest. We can also look at the Index in five year increments to compare changes over time.

 

Which of the existing water quality parameters are most appropriate to use in the Index?

Friends of Casco Bay currently monitors five physical and chemical water quality parameters through our Citizen Stewards Water Quality Monitoring Program: temperature, salinity, dissolved oxygen (DO), Secchi depth, and pH. Of these, three have been selected for use in the Health Index—DO, Secchi depth, and pH.

 

Dissolved oxygen (DO) DO is expressed as Percent Saturation in order to incorporate temperature and salinity. When water holds all the oxygen it can at a given temperature and salinity, it is said to be 100% saturated. At a given site during a given sampling event, temperature and salinity are measured, and DO is measured in milligrams per liter (mg/l) and then compared with the mg/l for 100% saturation in those conditions. We look at the distribution of the Percent Saturation data; we consider the lowest 10th percentile as the worse-case conditions for a particular site. That 10th percentile threshold, expressed as a Percent Saturation number, becomes a component of the Health Index for that site.

 

Simply averaging all the DO data for a site might obscure the full extent of any challenged conditions. For example, if a site is eutrophic, wherein nitrogen pollution levels have resulted in a huge algal bloom, there will be large swings in DO levels between the morning and the afternoon; simply looking at the mean would obscure these swings.

 

Secchi depth Secchi depth is a measure of water clarity. The Index uses a mean of the data to characterize each site. Sites with more organic matter and sediments in the water will be murkier and will exhibit reduced clarity, resulting in shallower (lower) Secchi depth measurements.

 

pH pH is a measure of the acidity of the water. pH data exhibit tremendous variability—diurnal differences through the day and seasonal shifts through the year. The Water Quality Monitoring Program requires that measurements be collected at 7:00 a.m. and then again at 3:00 p.m. on each monitoring day. This allows for a look at the change in conditions over the course of a day. The pH at a site is influenced heavily by respiration and photosynthesis. Respiration by algae, both seaweeds and phytoplankton, adds carbon dioxide to the water, which lowers pH. Measurements collected in the early morning, at 7:00 a.m., reflect the conditions found after a night of respiration and no photosynthesis. Photosynthesis of course requires sunlight and removes carbon dioxide from the water, raising pH. By afternoon, at 3:00 p.m., pH measurements will reflect the result of photosynthesis. The change between the morning and afternoon measurements, termed the diurnal swing, can be indicative of the magnitude of respiration and photosynthesis, and, indirectly, the amount of algae in the water. Since an excessive bloom of algae is one symptom of nitrogen pollution, a large diurnal swing in pH can serve as an indicator of excess nitrogen. A small change in pH is expected in a healthy, productive coastal system, but a relatively large swing can indicate a challenged site. We calculate the difference between the morning and afternoon readings, the diurnal swing, then amass that dataset to calculate the mean for the Health Index for that site.

 

What ranges are most appropriate for the component parameters?

For each of the three components of the Health Index, we have defined ranges, between which we would expect to see worse-case and best-case conditions. These ranges have been defined by looking not only at data for Casco Bay, but also data from other regions, state and federal guidelines, and relevant scientific literature.

 

Parameter: 0 point value 100 point value
Percent Saturation of Dissolved Oxygen 65% 95%
Secchi Depth (meters) 0.2 m 3.0 m
pH (diurnal swing) 0.4 0.1

 

How is the Health Index score calculated?

Each of the components calculated for a given site is plotted along the scale for that parameter. We use a natural logarithm formula to determine where on the scale of 0 to 100 a particular component falls. For example, a site’s calculated 10th percentile threshold for the Percent Saturation parameter will fall between 65% and 95% at a specific point on the scale between 0 and 100. The same is done for the Secchi depth component and the diurnal swing in pH. Now we have three numbers which fall between 0 and 100. These are added together and divided by 3 to obtain the mean, which is the Health Index score for that site.

 

How are the final Health Index scores presented?

After each site has a Health Index score associated with it, it can be classified as Good, Fair, and Poor, determined by score thresholds. A score of 85 and above is considered “Good”, a score of 70 to 84 is “Fair”, and anything below 70 falls into the “Poor” category.

 

What is eutrophication?

Eutrophication occurs when too many nutrients (and occasionally other factors) fuel explosive plant growth. While nitrogen is an essential nutrient in marine systems, too much nitrogen can become a pollutant when it triggers excessive algal growth. This growth can result in low DO measurements, shallow Secchi depth readings, and wide variations in pH.

Volunteer Andy Bertocci

Water quality monitoring season may be over, but the work continues

Volunteer Andy Bertocci
Andy Bertocci has been volunteering with Friends of Casco Bay for 25 years!

Volunteers, such as Andy Bertocci, finished their data collection on October 18, marking the end of the 2016 season. But, both for Andy and the organization, this also marks 25 years of data collection by Friends of Casco Bay!

Over 7 months, from April through October, our water quality monitors record their measurements of water temperature, salinity, water clarity, dissolved oxygen, and pH (the level of acidity of the water). They also make notes on weather conditions, air temperature, and any unusual or intriguing sightings, such as jumping fish, invasions of jellies, and the occasional oil spill.

Although our Citizens Stewards have turned in their data sheets and put their water quality kits to bed until next spring, the work continues back at the office, where staff members are busy. We are organizing, reviewing, and analyzing the data from 37 volunteer monitoring sites around Casco Bay.

Friends of Casco Bay Staff work on creating the Health Index

Database Assistant Sara Biron reviews the online data entries and enters additional data from spreadsheets entered by hand. She is the first to make sure the data makes sense; Citizen Stewards Coordinator Peter Milholland is responsible for checking it twice.

Peter explains the importance of this review, “Our volunteers are trained according to a comprehensive Quality Assurance Project Plan (QAPP) approved by EPA, which makes their data, after quality assurance checks by staff, scientifically defensible.”

Peter then passes the data along to Research Associate Mike Doan. Mike averages the data collected over the past five years for dissolved oxygen, pH, and water clarity (Secchi depth) to update the Casco Bay Health Index, an overview of the health of the waters around Casco Bay. Says Mike, “The Health Index enables us to assess: What is the relative condition of sites across a region? How does the health of regions of the Bay differ from each other? Which sites, based on the selected criteria, require a closer look? Are these conditions improving or degrading over time?

Development and Communications Associate Sarah Lyman then turns Mike’s analysis into an easy-to understand graphic, where each sampling site is assigned a color—red, yellow, or green—onto a map of the Bay. That chart lets everyone see the health of Casco Bay at a glance.

On January 24, Friends of Casco Bay will unveil the updated Casco Bay Health Index and show how different regions of Casco Bay are faring.

Join us on January 24 at our 2017 Volunteer Appreciation Celebration and Annual Meeting at the Hilton Garden Inn, Freeport (snow date 1/25).

Come spring, our volunteers will take up their kits once again, come in for their individual Quality Assurance review, and devote ten Saturdays in 2017, to helping us improve and protect the environmental health of Casco Bay.

Friends of Casco Bay, working with you to keep Casco Bay blue.

How can you keep Casco Bay blue?

Join us as a member by donating today!

Become a volunteer by filling out our volunteer application.

Learn what you can do to make a difference for Casco Bay in our Bay Paper.

Friends of Casco Bay’s mission is to improve and protect the environmental health of Casco Bay through research, advocacy, and education. Concerned citizens founded our organization in 1989, after a report labeled Casco Bay in southern Maine as one of the most polluted estuaries in the nation.

Since then, we have helped reduce pollution into the Bay through stewardship, monitoring water quality, education, and collaborative problem solving. We are on the water year-round, working to protect the water quality of Maine’s busiest Bay.

As a nonprofit conservation organization, we depend on the support of our 2,400 members, the volunteer efforts of more than 250 citizens, and the expertise of 10 staff and 21 Board members.

 

Photo by Kevin Morris

 

Mac Richardson Nabbing Nitrogen Photo credit: Dave Dostie

Nabbing Nitrogen: A water sampling “flash mob”

Too much nitrogen can turn Casco Bay from a healthy blue to an unhealthly green.

Mac Richardson Nabbing Nitrogen Photo credit: Dave Dostie
Mac Richardson Nabbing Nitrogen
Photo credit: Dave Dostie

On a rainy July 10, at precisely 10:10 a.m., 97 volunteers for Friends of Casco Bay hung out over docks or trudged through mud to collect jars of seawater. The analysis of their samples from sites along the Fore River in Portland and South Portland will increase our understanding of nitrogen levels in Portland Harbor. When we receive the lab results, our science staff will construct a map to show nitrogen concentrations at various sites around the harbor.

Already, these efforts have accomplished one of the main goals of the project: to explain to the public that excess nitrogen is one of the factors responsible for turning our mudflats an unhealthy green. All living things need nitrogen to grow, but an overdose can trigger excessive growth of nuisance algae, reduce water clarity, and lower oxygen levels. Sources of excess nitrogen in coastal waters include sewage, pet wastes, decaying plants and animals, and burning fossil fuels.

We partnered with Maine Department of Environmental Protection and the City of South Portland, and we raised funding for the project from Maine Outdoor Heritage Fund, RBC Blue Water Project, Casco Bay Estuary Partnership, Bowdoin College Common Good Grant, and our generous members.

Health Index Score over time for Custom House Wharf in Portland

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”.

Friends of Casco Bay Appreciates Its Volunteers

Photo: Will Everitt, David Brenneman, Lauren Leclerc, Stephen Brezinski, Beth Howe, and Mac Passano Not pictured: Don Gower, Michael Heskanen, and Darren McLellan (Credit Kevin Morris)

Friends of Casco Bay held its annual Volunteer Appreciation Event and Members Meeting on January 27th at the Harraseeket Inn in Freeport. Nine Citizen Stewards reached milestones in volunteering of 20 years, 10 years, and 5 years. These citizen scientists were recognized for their contributions to monitoring the health of the waters of Casco Bay. Many of the 170 guests at the event have volunteered for the marine stewardship organization in various capacities.

Darren McLellan has volunteered for Friends of Casco Bay for 20 years. He feels a deep connection to his water quality sampling site at Peabbles Cove in Cape Elizabeth. “My grandmother was a Peabbles, and my family has been here for a couple of hundred years.”

Will Everitt, Friends of Casco Bay’s Development Director, has volunteered as a back-up water quality monitor since he joined the staff in 2006.  

Mac Passano and his wife Beth Howe moved to Chebeague Island after retiring from teaching at the University of Wisconsin in 1991. They have been water quality volunteers at two sites on Chebeague for 10 years and 5 years respectively.

Don Gower retired after 40 years at B&M Baked Beans, where he rose from plant worker to plant manager. He has been sampling at Pinkham Point in Harpswell for 5 years.

Stephen Brezinski and his wife Roberta Brezinski sample water quality at Yankee Marina on the Royal River in Yarmouth. Steve was recognized for 5 years of monitoring, but he has been assisting Roberta unofficially for 17 years.  

Lauren Leclerc and David Brenneman, both professional wetland scientists, have been testing the water at Gun Point in Harpswell for 5 years. More recently, they have been joined by their infant daughter Elyse as an “honorary” monitor.  

Michael Heskanen also was honored for 5 years of service to Friends of Casco Bay’s Citizen Stewards Program. Michael travels by boat from his house in Brunswick to his water quality monitoring station at Indian Rest in Harpswell.

Blue Mussels: Hanging by a thread in Casco Bay

Ann Thayer on boat
Ann Thayer searches for mussel beds along the shores of Casco Bay.

When Ann Thayer goes out in her Boston Whaler, it’s not just to enjoy time on beautiful Casco Bay. This Friends of Casco Bay Board Member is scouting out mussel beds, and more often than not, she is not finding them.

Blue mussels (Mytilus edulis) are the common mussels found along the Maine coast. Ann explains, “In addition to providing a rich habitat for other sea life, dense mussel beds can provide protection to the shorefront against the effects of storm surges. Mussels are filter feeders, and they can siphon up to 25 gallons of water a day as they feed on microscopic algae and nutrients in the water column. In short, they are important contributors to the Bay!”

For the past few years, anecdotal accounts suggest that mussel beds once piled high with layers of living mussels are now all but gone. Ann, an environmental scientist by training, offered to lead a volunteer effort to survey the Bay to see if reports of disappearing mussel beds are true. Over the past two summers, she and a handful of other observers have looked at more than 25 areas between Portland and Harpswell, surveying by foot, kayak, and small boat.

Baby mussel spat, the floating plankton phase of mussels, appear to be plentiful in the water column. Commercial aquaculture growers are getting plenty of natural seed set on their ropegrown mussels. Juvenile mussels are being found on mooring ropes, wharf pilings, and floating docks. “It’s the intertidal and subtidal horizontal mussel beds that are missing,” Ann reports.

Dr. Brian Beal, Professor of Marine Ecology at University of Maine at Machias, and others suspect that bottom-dwelling crustaceans, such as lobsters, rock crabs, green crabs, and Asian shore crabs, may feed on baby mussels trying to establish a foothold on the ocean floor. But Brian says field testing is needed to prove or disprove this hypothesis. He suggests cordoning off some bottom areas from predators with cages or nets to see if juvenile mussels survive there.

Ann has found small juvenile mussels on flats in Brunswick. “What is disturbing is that when you do find pockets of mussels, they are just individuals of one age. You don’t find whole beds of mussels, with new mussels growing on older ones, like we used to see.”

Everyone seems to have a different theory as to why the once ubiquitous blue mussels have disappeared: green crabs and other predators, dragger nets destroying mussel beds, warming sea temperatures, and ocean acidification. Cathy Ramsdell, Friends of Casco Bay Executive Director/Casco Baykeeper Pro Tem, cautions, “There are a lot of theories, but there isn’t much research being done on the change in distribution patterns of blue mussels and the possible causes. All we have is speculation. Our current objective is to try to get a handle on presence or absence of beds along the coastline of Casco Bay.”

Ann Thayer says, “This project with Friends of Casco Bay is totally driven by citizen scientists. It’s another reason why our volunteers are so important. We are looking for people with small boats who can survey the eastern part of the Bay from Brunswick to the New Meadows River.” If you are interested in joining the search, contact Friends of Casco Bay at keeper [at] cascobay [dot] org.