Eelgrass Health and Restoration

Eelgrass is a marine flowering plant that provides the foundation for our harbor environment. The value of eelgrass meadows is well documented and includes stabilizing sediments, reducing wave energy, serving as a “carbon sink” to help offset our carbon footprint, and improving overall water quality. As our island community searches for answers to more severe storms and rising seas, we can look to nature for solutions that have been working for Nantucket for thousands of years. These meadows provide habitat for many commercially important and/or endangered species, such as the last commercially viable “wild” bay scallop fishery in the U.S. However, the abundance and health of eelgrass has diminished from historic levels in many areas. Over the years the Nantucket Land & Water Council (NLWC) has supported eelgrass research that has revealed a need for action.

In conjunction with the Town of Nantucket and a grant from the NLWC and Great Harbor Yacht Club, Charles Costello from the Massachusetts Department of Environmental Protection conducted a detailed eelgrass survey of Nantucket. His results highlight the stark decline of eelgrass in the past few decades. Click here to read his report: 2015 Nantucket Eelgrass Mapping(PDF).

The Nantucket Land & Water Council, led by Dr. Alyssa Novak, a Research Assistant Professor at Boston University, and with extensive support from a wide range of community partners, including the Nantucket Natural Resources Department, Anderson’s Stillwater Moorings, The Sunken Ship, and countless volunteers, has successfully transplanted over 15,000 shoots of eelgrass from donor sites to the half-acre restoration area in Nantucket Harbor.

The plants that survived have taken root and begun to spread across the area through their root system and seeds. The process would not have been a success without the assistance of the Nantucket Harbormaster Sheila Lucey and her team for closing the site to shell fishing and boating, as well as the good faith of scallopers, fisherfolk and boaters who have stayed out of the closed area as the plants recovered. For a detailed look at how the project has done so far, Dr. Novak’s latest progress report can be found here: ACK Eelgrass Restoration 2020

In 2021, NLWC applied for and received an extension of the three-year permit at the Monomoy restoration site to begin testing new methods of eelgrass restoration. While our project has been successful, diving to physically transplant eelgrass shoots on the Harbor bottom is slow and expensive work requiring certified scuba divers and equipment. We are testing new seeding methods that will be more cost-effective and less time-consuming, allowing us to restore more extensive areas of Nantucket’s harbors in less time. These seeding methods, which involve collecting adult reproductive eelgrass shoots and holding them in flow-through tanks until they drop their seeds, have been successfully applied in other areas, such as the Chesapeake Bay and China! Many factors such as currents, seed predators, and human interference can affect how these methods will perform, so NLWC is working with Dr. Novak and the Nantucket Natural Resources Department on a pilot seeding project.

In Fall 2024, we also hope to begin seeding work at a new restoration site off of Coatue’s 4th Bend—another area that once held abundant eelgrass. A generous grant from The Agua Fund is supporting this ongoing restoration work.

The NLWC will continue to use the information we collect, compare it to other eelgrass communities in our region, and work to improve this critical natural resource through research, education, and advocacy.

Dr. Novak conducted a health assessment in 2018 that detailed the condition of our eelgrass meadows. Physiological characteristics of eelgrass meadows at 6 locations were evaluated, including leaf length and width, plant density, above- and below-ground biomass, and epiphyte cover. Sediment cores and eelgrass tissue samples were analyzed for nutrient content, and environmental conditions were monitored by installing temperature and light sensors throughout the harbor.

This health assessment research was made possible by a Great Harbor Yacht Club/Nantucket Land & Water Council Marine Grant with support from the Nantucket Shellfish Association. We thank the GHYC and the NSA for their support. Read the full Nantucket Harbor assessment here: 2018 NLC Nantucket Harbor Eelgrass Health Assessment

The NLWC will continue to assess the overall health of eelgrass meadows throughout Nantucket and Madaket harbors. This will include examining nutrient impacts on eelgrass in Nantucket and comparing it to the health of eelgrass in other regional communities along the North Shore and Cape Cod.

Your contributions to The Water Fund enable the NLWC to continue working with eelgrass specialists from Boston University to oversee and assist with the health assessment and restoration work.  Click here to join us in protecting and preserving our water resources!