Have you seen blue mussels lately? Help scientists track the once-abundant bivalve

We know that our intrepid Harwich Conservation Trust (HCT) community is always ready to pitch in for citizen science efforts. Well, here’s a chance to “flex your mussels” and contribute to a study that is tracking the story of a bivalve that appears to be in decline.

The Association to Preserve Cape Cod (APCC) is gathering both current observations and anecdotal information about blue mussels in our region. They are asking residents, folks who shellfish, municipal staff, beach walkers, boaters, anglers, naturalists, and anyone with knowledge of local shorelines to share what they have seen.

Five regions of the MassBays National Estuary Partnership are working together to track blue mussel abundance across Massachusetts, with APCC coordinating the Cape Cod effort.

Blue mussel information from APCC

For decades, blue mussels were one of the most familiar sights on New England’s rocky shores. They formed dense beds along intertidal shorelines, jetties, pilings, and other hard surfaces, creating habitat for small marine life and providing food for fish, birds, and other coastal species.

However, across the region, scientists have documented major declines in wild blue mussel populations over the past several decades. In some places where mussel beds were once thick and widespread, they are now sparse or nearly absent.

Blue mussels are considered a foundation species because they help shape the intertidal community around them. Mussel beds provide shelter for small marine animals, serve as an important food source, and help filter coastal waters.

When mussels disappear, the shoreline community changes with them.

Complex causes of decline

The causes of these declines are complex. Warming air and water temperatures, predation from invasive European green crabs, pollution, storm impacts, and other changing coastal conditions may all play a role. One of the biggest challenges to tracking the decline is understanding where mussels were historically abundant, where they remain today, and where people have noticed changes over time.

Have you noticed blue mussels in your area? Do you remember places where mussels used to be more common? Have you seen changes along a favorite beach, harbor, jetty, rocky shoreline, or dock? Please consider taking a brief survey to help us better understand Cape Cod’s blue mussel history and current distribution.

Your observations can help provide important local context and guide future monitoring, research, and restoration efforts across Cape Cod and Massachusetts.

Click here to take the survey or scan the QR code in the APCC photo. Thank you!

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