What Four Years of Reef Data Tell Us

Building a reef is the exciting part. Measuring it, season after season, is how we know it's working. Since 2022, East Hampton High School interns have monitored every South Fork Sea Farmers reef, counting oysters bag by bag and tracking survival, shell growth, water quality and natural set.

Here's what the numbers through 2025 show.

Reef #1, Accabonac Harbor (installed September 2022)

Survival was 98.2% at the first count and 96.9% at the second. Shells grew from 3.3–3.7 cm to 3.5–4.1 cm in the first eight weeks. The big news came in June 2024: monitors found juvenile oysters that had settled on the reef without any hatchery seeding. The reef is reproducing on its own.

Reef #2, Accabonac Harbor (installed December 2023)

Average spat size grew from about 17 mm at installation to 80.2 mm in the deep bag and 72.8 mm in the shallow bag by October 2024, nearly fivefold in 44 weeks. Survival fell to 60.5% in December 2024, then rebounded to 86.7% by October 2025.

Reef #3, Accabonac Harbor (installed July 2024)

Survival was 82.1% at the October 2024 count. Spat grew from 4.1 cm to 5.9 cm by October 2025, a 44% increase year over year.

Reef #4, Three Mile Harbor (installed July 2025)

Survival was 85.5% at the October 2025 count. This is our first reef outside Accabonac, and it shows the model can work in other East Hampton harbors.

Why this matters

A reef that survives is good. A reef that reproduces is the goal: it means the bay is starting to restore itself. Every surviving oyster is filtration capacity our harbors didn't have before, working against the nitrogen that fuels algal blooms and bacteria.

It also matters who is collecting this data. These are high school students doing real field science, presenting to the Town Trustees, and seeing the results of their own work.

Read the full Reef Report Card, and help us keep building. Every gift goes into the water.