Safe, Healthy Shellfish - Land Use is Part of the Picture

While increasing the number of clam flats that are open to harvesting does not directly correlate to increased clam landings, the University of Maine at Machias Marine Ecology Department concludes that the size of the harvest can increase as a result of multiple factors:

• Better management of shellfish areas,
• Addressing predation,
• Shellfish habitat conservation,
• Limiting closures to only the extent necessary to protect public health,
• Expansion of shellfish aquaculture,
• Marketing and promotion to enhance the economic value of the shellfish industry, AND
• Improvements in water quality.

Water quality testing is a significant factor in choosing to close or open clam flats. Landowners and municipal officials can focus on land use decisions that affect water quality, while recognizing all the other factors.

 

Land Use Affects Water Quality

When it rains, pollution happens. Developed areas have five times the amount of run-off than what is generated by buffered, vegetated areas. Developed areas contribute the following pollutants into the water:

• Sediments
• Bacteria
• Temperature increases or spikes
• Nutrients
• Petroleum derivatives
• Pesticides
• Herbicides
• Heavy metals

More than 180,000 acres of Maine’s coastal waters are classified as having impaired water quality under normal conditions. Shellfish harvesting is prohibited or restricted in these areas.

Rough calculations suggest that annual losses in gross harvester sales of soft-shell clams could range from $288 to $14,400 per intertidal acre of suitable clam habitat, according to research prepared by Dr. Kevin Athearn of the University of Maine at Machias.

 

What can landowners and municipal officials do?

Landowners and municipal officials support shellfish by learning where pollution originates, sharing stories and providing education, and then taking action to address water quality concerns. Funding sources and assistance are also identified on these pages:

• The landowner toolbox contains information and actions available to address water quality
• The municipal toolbox contains resources and approaches available for local officials
• Mudflats Mapped--find your watershed, identify the hot spots
• Raise awareness with services provided by WCCOG
• Find partners and other resources