Current Conditions

Planning to swim, paddle, or dig clams? These sources are updated by the agencies and organizations that monitor our waters. We link to them rather than repeating their information, so you always get the latest.

Cyanobacteria (blue-green algae) advisories

MV CYANO — Great Pond Foundation and Island Boards of Health Weekly monitoring of cyanobacteria in Island ponds during the warm months, with color-coded status for each pond, from no bloom up to a bloom advisory. Blooms can produce toxins harmful to people and especially to dogs. Check before swimming or letting pets in the water in mid to late summer. greatpondfoundation.org/mvcyano

Shellfishing: what's open and closed in Tisbury

Tisbury Shellfish Department The Shellfish Constable is the authoritative source for which areas of Lake Tashmoo, Lagoon Pond, and Vineyard Haven Harbor are open. The department also sells permits, sets season dates, and publishes the town shellfish regulations and area maps. Office at 19 Owen Park, 508-696-4249. tisburyma.gov/203/Shellfish

Massachusetts Division of Marine Fisheries Emergency shellfish closure and reopening notices, often issued after heavy rain, plus the state's shellfish area classifications. Note: the state's classification maps show how areas are managed, not whether they're open today. Always confirm with the Shellfish Constable before harvesting. Emergency closure notices · Shellfish classification areas

Beach water quality

Massachusetts Department of Public Health Bacteria test results and swimming closures for public beaches statewide, including Tisbury's. Updated daily during the beach season, roughly Memorial Day to Labor Day. Select "Tisbury" to see local beaches. mass.gov/beachdata

Pond water quality over time

Martha's Vineyard Commission Summer water-quality monitoring results for Lake Tashmoo, Lagoon Pond, and other Island ponds. This is the place to see long-term trends rather than today's conditions. Ponds of the Vineyard

Links checked: 10/2026