Help Track a Surprising New Arrival on Our Shores

For WHOI Sea Grant/Cape Cod Cooperative Extension’s marine team, it started with a text message back in the spring of 2023:  “Any idea what this strange clam is?” And from there a story has begun to unfold. Spotted by commercial harvesters in Chatham and Wellfleet, Manila Clams (Ruditapes philippinarum) had not been documented in New England waters, but are extensively farmed on the West Coast.

Working with the Center for Coastal Studies, the marine team started to document sightings of Manila Clams on the Outer Cape.  They enlisted the assistance of scientists from across the region who specialize in marine invasive species to see if anybody else was noticing them.  At around the same time, research groups in the Boston area were starting to see these clams in their environment surveys in the Greater Boston Harbor area.  Many of these sightings are documented on the citizen science website iNaturalist.

Collectively, the groups are still in the early stages of understanding the full extent of where these clams are, how they got here, and how they will affect our native clam species.  We ask that anybody who might be out on the flats and might run across one of these clams document it and either submit a report to iNaturalist or email aputnam@umass.edu with your sighting. Please include the following information: a photo, state if found alive or dead, estimate of length, and the number of clams found.