The Nature Conservancy. Protecting nature. Preserving life.™

In the 1970s more than half of the hard clams eaten in the entire United States came from the Great South Bay. When clams were abundant, they also filtered 40% of the water in the Great South Bay — every single day. 

But overharvesting caused a great decline in shellfish populations, and today there are only enough hard clams to filter about 1% of this vast body of water daily.

The Circle of Life

Without shellfish, water quality declines - and creatures that depend on clams, scallops, and oysters as a food source (including humans!) also suffer.

Clams, scallops and other bivalves are filter-feeders. Without them in abundance, harmful algae blooms (also known as brown tide) can become worse. Brown tide also shades seagrass meadows, preventing them from getting ample sunlight, and seagrass provides a home for shellfish to live! This has probably caused further harm to the shellfish population.  

In some areas of Great South Bay shellfish numbers are so low that they are unable to recover on their own.

Giving Shellfish a Fighting Chance

In 2004, The Nature Conservancy acquired 13,400 acres of underwater land in Great South Bay. This land, known as bottomlands, has provided us with an opportunity to restore the clam populations so important to the ecosystem of Great South Bay.

“After stocking more than 3.5 million adult clams into the bay, we couldn’t be happier to see the clam population start to show initial signs of recovery for the first time in decades,” said Carl LoBue, senior marine scientist for The Nature Conservancy on Long Island. “We are excited about our progress, and have laid out a solid foundation to continue, but we also recognize that the commitment and patience of our partners will be needed to reach our goals.”

Along with eight government agencies, scientific experts, and community interests, the group in the process of developing a long-term plan to restore a robust self-sustaining hard clam population to Great South Bay by 2020.

Successful Findings to Date:

• More Adult Clams = More Baby Clams
  It’s as simple as it sounds. Clams need to be close together in proximity in order to reproduce. We stocked a high density of adult clams into protected areas in our underwater sanctuary and “pow!” baby clams were made. The number of babies born in 2007 exceeded even The Nature Conservancy’s optimistic projections.
• Clam Larvae ‘Go With The Tide’
  Just like kids off to college, free-swimming clam larvae spread and settle over areas that are hundreds of times the size of the protected areas they are from. This news is very encouraging, as there was concern that Great South Bay may no longer be a suitable environment for clam production.

Current and Future Challenges:

• Drink Plenty of Clean Water
  Clams help filter water and keep it clean, but they also need clean water to survive. Great South Bay’s clam population remains susceptible to harmful algal blooms. Case in point: the most severe brown tide on record started in 2008 and stretched into 2009. This affected the survival and growth of juvenile clams, and impacted the survival and spawning of adults.
   
• You Can’t Survive on Potato Chips
  Even without brown tide, poor nutrition poses a problem for clams. Poor food quality in Great South Bay reduces spawning and slows growth, leaving juvenile clams susceptible to predators for longer, making this water body a more challenging growing environment than some other Long Island waters.

The Nature Conservancy and its partners are working throughout Long Island to make our waters thrive once again...and here's how we're doing it:

• restoring shellfish populations by creating "spawner sanctuaries" and shellfish nurseries where clams and scallops can grow, reproduce, and live safely.
• monitoring the role shellfish play in improving our water quality, controlling harmful algal blooms, and enhancing habitat for other marine life.
• engaging partners to help us in our mission to restore the Great South Bay to its former health.