Marine Invasives

Marine Invasives


Barnstable Clean Water Coalition

Marine invasive species are animals and plants that are not naturally occurring in a location, but were transferred and introduced there by other means, including boats, trailers and fishing equipment. These non-native invasive species can wreak havoc on a local ecosystem and overtake naturally-occurring plants and animal species’ habitats.

Since 2009, Barnstable Clean Water Coalition has been involved with the Massachusetts Office of Coastal Zone Management’s (CZM) Marine Invader Monitoring and Information Collaborative (MIMIC). MIMIC is a network of trained volunteers, scientists, and staff from state and federal agencies who monitor marine invasive species throughout the Northeast. Data collected by MIMIC provides an early warning system for invasive species, helps identify new invasive species in the region before they spread, and improves our understanding of the ecology and behavior of established invaders.

Barnstable Clean Water Coalition monitors four different sites throughout the estuary four times a year, usually from July through September when the bays’ waters are warmer and more inviting to these marine intruders. The sites we monitor are a floating dock at the Wianno Yacht Club, the fixed dock at the Cotuit Town dock, the cobble shore on Dead Neck Island, and a private floating dock in North Bay.

At each site, water and air temperature, salinity, and weather conditions are recorded on data sheets. Barnstable Clean Water Coalition monitors for 16 established introduced species and 7 potential invaders that are identified using Marine Bioinvader ID cards developed by Salem Sound Coastwatch and CZM.

After an initial site assessment to determine what marine species – native or invasive – are present, samples of organisms are collected and identified to determine whether they are native or invasive species. The abundance of each invasive species is reported on the data sheets. Information collected at each monitoring site during each monitoring event is entered online into the Marine Invader Tracking and Information System (MITIS) database.

2017 Update

The 2017 Marine Invader Monitoring and Information Collaborative (MIMIC) season was busy and informative with BCWC adding an additional monitoring station at Millway Marina on the north side of Barnstable near Cape Cod Bay.

Last year, our monitors observed extremely high levels of tunicate growth on docks in both Cotuit and West Bay at the beginning of the summer. The Dead Neck Island station had the same invaders that were seen last year, the Asian Shore Crab (Hemigrapsus sanguineus) and Dead Man’s Fingers (Codium fragile). At our new monitoring station in Barnstable Harbor at Millway Marina, we saw the highest growth of tunicates on docks near the end of summer, mid to late August. No new or potential invaders were observed at any of the BCWC monitoring stations.

Sheath Tunicate 1
Club, Star, Sheath
Striped Sea Anemone 6
Star Tunicate 1
Skeleton Shrimp


Barnstable Clean Water Coalition