Oyster reefs are among the most threatened marine habitats on Earth. Roughly 85% have disappeared in less than 150 years — since the late 1800s — and in more than a third of the bays studied they are now functionally extinct.1
Where we are
- Chesapeake Bay, USA — native oysters are at about 1% of historic levels.2
- Europe — more than 95% of native flat-oyster reefs are gone.3
- Australia — over 90% of shellfish reefs have been lost.4
Why it happened
- Industrial commercial dredging — the leading cause: 19th- and 20th-century commercial fleets dredged reefs away faster than they could rebuild, stripping the shell young oysters need to settle on.
- Chemical pollution & runoff — today’s biggest barrier to recovery and the hardest to reverse: fertilizer and sewage nutrients fuel algae blooms and low-oxygen dead zones, while industrial chemicals, pesticides and heavy metals poison the water oysters filter.
- Disease — MSX and Dermo parasites devastated weakened populations.
- Lost habitat — coastal development and altered freshwater flows destroyed reef ground.
- Climate change — human-caused global warming is heating coastal waters, and the CO₂ the ocean absorbs makes it more acidic, dissolving the shells young oysters build. Stronger storms and rising seas add to the stress.
Why it matters: one adult oyster filters up to 50 gallons of water a day; reefs shelter fish and crabs and shield shorelines from storms.
🦪 The good news: restoration works — but it can’t do the job alone. Lasting recovery also means stopping the causes: ending destructive industrial dredging, cutting chemical pollution at its source and protecting the coasts reefs depend on. Harvesting done right isn’t the problem — as the old oystermen say, “the beds like to be worked.” Beds that are worked with care can be cultivated and helped to thrive. This project is dedicated to both.