Our approach to conservation is ecosystem-based.

We use the natural environment to solve the problems humans have created. We have implemented six innovative programs that focus on mitigating contamination and restoring the bay for fishing and recreational use.

Revitalizing the bay one oyster at a time


Creating a market for the invasive green crab


Tracking the health of Quahog Bay


Fishing for plastics


Removing pollutants that contaminate our waters


Educating current and future stewards


QBC’s Sustainable Oyster Aquaculture program, otherwise known as Snow Island Oysters, demonstrates a powerful method of naturally cleaning the ocean environment while generating funding for our conservation operations.

Oysters are an integral part of marine ecosystems, improving water quality. While filter feeding, each adult oyster can process one to two gallons of water per hour, removing algae, plankton, and other particles that impact water clarity. In addition, oysters may mitigate the effects of nutrient pollution in coastal waters by fixing nitrogen and phosphorous in their shells, tissues, and excrement.

QBC’s Sustainable Oyster Aquaculture program has made significant progress toward restoring Quahog Bay while reinvesting 100% of the proceeds from Snow Island Oyster sales in our conservation activities in the bay—creating a sustainable self-funding model for local environmental action. Please visit the Snow Island Oyster page for more information.

Growing oysters is a delicate process. A hatchery grows the larva. In about three weeks, the larvae go through what is known as settlement, the process by which a larva fuses itself to a tiny fragment of oyster shell. At this point, the tiny oyster is only 1.5 to 2mm and is called a seed.

We buy the seed from local Maine hatcheries. When the seeds are delivered they are immediately placed into QBC’s upweller, a specialized tank system that functions like a nursery for infant oysters.

The upweller’s job is to help the oysters grow as fast as possible to a size that can be safely handled with a limited risk of mortality. It works by pumping fresh, nutrient-rich water up through a mesh screen on which the tiny oysters rest. The animals filter the nutrients from the upwelling water. In about three weeks they grow rapidly from just a couple millimeters to a half-inch or more.

The oysters are then transferred to mesh bags, which are placed in our floating cages around both Snow and Dogs Head Island. From there the oysters require two years to reach maturity. They are then sold to restaurants, markets and seafood distributors.

At any given time we have about 600,000+ oysters in cages around Snow Island. Within a few years we intend to increase that number to almost one million.

100% of the proceeds from the sale of our oysters are returned to the QBC to fund our many programs to clean the bay.

Please ask for Snow Island Oysters at your favorite market or restaurant. We think you’ll agree, being green never tasted so good.

We are currently in the process of setting up our online order forms. For now, to purchase Snow Island Oysters, please call our office number (207) 522-1105 or email

You can find them locally at:

Glidden Point Oyster Co.
637 River Road
Edgecomb, ME 04556
Phone: (207) 315-7066

Gurnet Trading Co
602 Gurnet Rd,
Brunswick, ME 04011
Phone: (207) 729-7300

The Shop
123 Washington Ave,
Portland, ME 04101
Phone: (207) 699-4466

There are innumerable microscopic algae drifting through the ocean. These tiny algae are essential components of ocean life, fueling the food chain by harnessing energy from sunlight. However, when supplied with excess nutrients that flow down river from inland areas, they can multiply uncontrollably and smother nearby ocean life.

This can happen naturally, as rivers flood and carry nutrient-rich soil from forests and grasslands, but it can also happen when fertilizer and excrement from livestock travel down those same waterways or when coastal development leads to excess erosion. Some algae species, like the dinoflagellate Karenia brevis, color the ocean surface a deep red, inspiring the name “red tide.” But not all red tides are red, and not all of them become dense enough to color the water.

Red tide can be harmful to both the environment and humans. In Maine, we monitor for dinoflagellates that are dangerous to human health if consumed, specifically Alexandrium, Pseudo-nitzschia, and Dinophysis.

Paralytic Shellfish Poisoning (PSP): Alexandrium does not usually produce red water, however it is referred to as “red tide.” People usually display PSP symptoms within two hours of consuming impacted shellfish. Mild symptoms include numbness and tingling of the face, arms, and legs, followed by headache, dizziness, nausea, and muscular incoordination. Severe poisoning causes muscle paralysis and respiratory failure within two to 25 hours.

Diarrhetic Shellfish Poisoning (DSP): As the name suggests, this syndrome manifests itself as diarrhea and abdominal pains. Nausea and vomiting may occur too. DSP is caused by Dinophysis, and its symptoms usually set in within a half-hour of ingesting impacted shellfish. Symptoms last for about one day, and recovery usually occurs within three days, with or without medical treatment.

Amnesic Shellfish Poisoning (ASP): If high levels of Pseudo-nitzschia are consumed, symptoms will include vomiting, nausea, diarrhea, and abdominal cramps within 24 hours of ingestion. In more severe cases, neurological symptoms develop within 48 hours and include headache, dizziness, confusion, disorientation, short-term memory loss, motor weakness, seizures, profuse respiratory secretions, cardiac arrhythmias, coma, and possible death. Short-term memory loss can be permanent.

It is important to know when shellfish are safe to collect and eat. Toxic shellfish can be found even in clear, clean, and remote waters off the coast of Maine. Toxic shellfish do not look or taste any different from non-toxic shellfish and toxins cannot be cooked out.

For updates on whether it is safe to harvest in a specific area, visit the State of Maine Department of Marine Resources website.


Green Crab Harvesting Sites

The European green crab (Carcinus maenas) is one of the most aggressive invasive predators in coastal marine systems, having established itself on every continent except Antarctica. The green crab came to the Atlantic coast of North America nearly 200 years ago, and today is one of the most ecologically and economically damaging predators. Our cold waters had kept their population in check, but now, with the Gulf of Maine warming 99% faster than any other world ocean, the green crab populations have rapidly expanded in size and range.

Green crabs consume nearly everything in their paths, destroying mussel beds, clam flats, and scallop stocks. This has devastating impact on local fishers who depend on shellfish production for their livelihood. In addition, green crabs slice through eelgrass habitat and burrow in salt marshes, causing increased erosion in bays and estuaries.

As the forces of climate change continue to amplify this threat, new strategies are needed to mitigate its ecological and socioeconomic impacts. QBC has developed a localized management plan that investigates and collects data on green crab population dynamics. We will use that information to increase our catch per unit effort (CPUE) and learn more about the species. Our management plan includes a) Prevention and Containment; b) Detection and Forecasting; c) Removal, Control, and Mitigation; and d) Data Management and Education.

QBC’s management plan takes a three-phase approach that aims to solve the green crab crisis.

Phase I: Remove Green Crabs. It is highly unlikely that we will ever be able to eradicate them entirely. Yet, to alleviate the pressure that green crabs have put on our ecosystem, we want to remove as many as we can. As the largest green crab harvester in Maine, QBC has developed harvesting methods that remove thousands of pounds of green crab each year.

Phase II: Research Green Crabs. We collect data every time we fish for green crab. We track their abundance in Quahog Bay and population trends from May through November, creating a database for monitoring year to year.

Phase III: Develop a Lucrative Fishery. Our goal is to create a viable product that would provide a new source of economic opportunity for fishers and coastal communities. Utilizing an invasive species to diversify fisheries’ resources may ultimately enhance the future resiliency of Maine’s coastal communities. This could serve as a model for how to mitigate and adapt to the ecological and socioeconomic impacts of climate-driven change.

QBC has partnered with local fishers to investigate the viability of green crab as a fertilizer. We are partnering with businesses and other stakeholders in our marine ecosystem to identify and develop other ideas for eradicating the green crab.

Figure 1. The total number of green crabs and the net weight fished from 11 different
coves in Quahog Bay (see Image 1). Data collection began on July 7, 2019, summing to
8,470 individuals with a total weight of 1,350 pounds (last updated 9/12/19).


Water Quality Monitoring Sites

Each week, the QBC team collects water samples at nine different sites in Quahog Bay. Data is collected from the surface waters at each location and then processed and analyzed in our lab. We collect measurements of temperature, salinity, pH, and dissolved oxygen. In addition, we monitor levels of bacteria and various species of phytoplankton in order to track harmful algal blooms (HABs), more commonly known as “red tide” (visit our Snow Island Oyster Page: “What is Red Tide?” [LINK] for more information).

What do these measurements tell us about water quality?

Temperature – Research has shown that the Gulf of Maine is warming 99% faster than any other world ocean. We collect temperature data in Quahog Bay to monitor local trends and the seasonal turnover of the water column.

Salinity – Salinity is the amount of dissolved salts in water. On average, the salinity of seawater is 35 parts per thousand (ppt), meaning there are 35 grams of dissolved salts in every one liter. Freshwater has a salinity of 0 ppt. After a heavy rainstorm (a large freshwater influence), we often observe lower salinity values in the surface waters.

pH – The scale by which “acidity” is measured. Acidity indicates the concentration of hydrogen ions in a liquid. Biological, physical, and geological processes all naturally affect acidity levels, but human influences such as CO2 pollution can also impact ocean pH. A drop in pH indicates an increase in ocean acidity, which can affect shellfish by inhibiting calcification (skeleton/shell building).

pH scale with examples of common solutions and their pH values (NOAA)

Dissolved Oxygen (DO) – The amount of oxygen present (dissolved) in water. All aquatic animals need DO to breathe. Lower oxygen levels often occur in bottom waters where organic matter is decomposing and microorganisms are consuming DO. DO levels below 3 milligrams per liter (mg/L) raise concern for poor water quality that cannot sustain many species of marine life.

Bacteria – Bacteria are a natural part of microbiology. We test for the presence of disease-causing organisms or pathogenic bacteria, which indicate that the water has been contaminated with the fecal material of humans or other animals.

Phytoplankton – Phytoplankton are the foundation of the marine food web. Cell counts of different species of phytoplankton inform us about the abundance of each species in the seawater. Many species bloom in the spring and fall, but some are toxic to humans and have been categorized as harmful algal blooms (HABs) and/or red tide (see Snow Island Oyster Page: “What is Red Tide?” for more information).

We have identified six OBD systems and have removed and replaced four of them. We are currently negotiating with the last two property owners to update their systems.

In 2018,  QBC team was trained by DMR Public Health Officials to be phytoplankton volunteers. We collect water samples in the spring, summer, and fall using field microscopes to identify toxic phytoplankton species. Volunteers work independently after receiving training and equipment needed to collect samples.

Figure 1. Average temperature and salinity measurements of surface water in Quahog Bay during the summer of 2019. Data was collected from 9 different sampling locations (see Image 2) and averaged for each date.

Figure 2. Average surface water pH and dissolved oxygen (DO) of 9 different sampling sites in Quahog Bay (see Image 2). Data collection began on June 25, 2019 and was last updated August 13, 2019.


Since 2014, we have removed hundreds of cubic yards of marine debris from the bay— enough fishing gear, Styrofoam, bottles, cigarette butts, tires, and even car batteries to fill massive dumpsters.

If we see trash on the water or on the shore, we go get it. But we don’t stop there. We have certified divers on staff who use SCUBA gear to find and remove trash from the seabed, and we have a boat with a mechanical lift to haul heavy debris to the surface.

We also work to educate the community about the impact of trash on the health and beauty of the Quahog Bay.


An ounce of prevention is worth a pound of cure. To that end, QBC offers free, on-call pump-out service to any boats anchored within the boundaries of Quahog Bay. We pump waste from boats and transport it to a local licensed facility, potentially preventing thousands of gallons of black wastewater from being discharged into the bay every year. We also educate boaters about our free service and encourage them to take advantage of it.

One of our most impactful initiatives to date has been to locate, remove, and replace Quahog Bay’s antique sewage systems with eco-friendly contained systems. For many decades, the waters of Quahog Bay have been plagued by a handful of turn-of-the-century septic systems on older properties. These legacy systems (known as Overboard Discharge Systems, or OBDs) pump their untreated sewage directly into the bay. This sewage was the primary driver of Quahog Bay’s shellfish harvesting ban.

If your boating plans call for a visit to Quahog Bay please call the QBC Pump Out phone for service at (207) 522-1105.

We’re here to pump you out!


Monday – Friday: 8:00 am – 3:00 pm
Saturday & Sunday: Sporadic – volunteers choice


  1. Boat Description
    1. Name
    2. Color
    3. Sailboat/Powerboat
  2. Location
  3. Desired day and time for a pumpout
  4. Estimated number of gallons needed to be pumped


Our Education & Outreach program strives to create a balanced relationship between our community and the natural world. The program works by engaging community members with the marine ecosystem in a meaningful way, with the goal of promoting and enhancing environmental stewardship.

To encourage the development of Maine’s future marine scientists, QBC supports senior-level research projects by undergraduate students attending any university in the state. Since 2016, we have allocated $10,000 from our annual budget to support student capstone projects. Additionally, we work with local high schools to create hands-on opportunities for the next generation of environmental stewards.

QBC also hosts a number of educational events and workshops. Check the “Take Action” page on our website and follow us on social media for upcoming opportunities.

Rachel Borisko, Winner 2018
Published Research on Research Gate


Aidan F. Coyle, Winner 2017

Connor Daugherty, Winner 2017


Cassandra Lopez, Winner 2017

Caroline Foy, Winner 2017

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