May 21, 2018
Contributors Latest News | Poll Questions | Marijuana Ties | Mary Mayhew | Car Theft

Look at the science. Maine harvesting of rockweed is sustainable

Ben McCanna | The Forecaster
Ben McCanna | The Forecaster
A piping plover nestles into some dried rockweed Sunday, May 25, at Crescent Beach State Park in Cape Elizabeth, while 4-year-old Johannes Wendlen of Boston, Massachusetts, strolls past.
By Susan H. Brawley, Special to the BDN

I’m writing to disagree with the June 1 BDN OpEd by Peter Neill, “Regulate rockweed: How Maine’s rocky coast is being stripped bare.” I am a well-known tree-hugger in northern Maine, have been a life member of the Sierra Club since the early 1980s, and have published more than 60 research articles on Maine rockweeds and other aspects of coastal marine ecology.

I’m not about to support any fishing or other extraction industry that cannot prove itself to be sustainable. But this is a case where the data are clearly established: The harvesting of the rockweed Ascophyllum nodosum is sustainable.

Rockweeds are important to the coast of Maine, and we need to keep a close eye on the health of all our marine species, especially of habitat formers. But extensive scientific research and centuries-long sustainable harvesting across the North Atlantic show that a certain amount of harvesting is indeed sustainable. Therefore, I ask all Mainers interested in this issue to read about this rockweed, its uses, and how it is harvested in Maine in the recently drafted rockweed fishery management plan, available at

This plan was prepared by the Maine Department of Marine Resources and the Rockweed Plan Development Team, which consisted of a diverse group of stakeholders. I was a member of this team, and I believe that we produced a comprehensive scientific plan that can provide adaptive management into the future to protect the sustainability of the resource and its ecological roles.

Neill may have been unaware that the industry is already regulated in various ways by the marine resources department, including by licensing, landing fees, required reports on rockweed landed and cutting height protections.

Rockweeds are a vital resource in Maine, contributing about $20 million to the economy each year, providing jobs and producing “green” products, including concentrates that increase root mass and vigor of many agricultural crops in the U.S. when they are used as foliar sprays. Other products include supplements that supply vitamins and micronutrients in animal feeds.

In no way is the coast of Maine being “stripped bare by rockweed harvesters,” as Neill said. However, each year a substantial amount of the total rockweed on the Maine coast is removed by storms and ice shear. Indeed, ice shear can strip an area bare — but not for long, as this rockweed has evolved to resist the frequent natural disturbance of its environment and has amazing regenerative capability.

Rockweed harvesting is sustainable when it removes only a fraction of the total standing biomass and leaves the lower section intact, thereby maintaining the ecological roles of this habitat former and its natural regeneration. This is how harvesting is practiced on the Maine coast, which is why it is sustainable.

The fishery management plan discusses many scientific studies that show that rockweeds are resilient to environmental and human disturbance. It also provides references that support the conclusion that a sustainable harvest level for rockweed exists.

In fact, as mentioned above, not only is this species harvestable, it also loses so much biomass to storm and ice damage that the approximately 1 percent of total Maine biomass that is harvested is small by comparison. For example, studies in Cobscook Bay by Robert L. Vadas Sr., Wesley A. Wright and Brian F. Beal showed annual natural losses of 29-71 pe rcent of standing biomass at five study sites, with an average loss of 54 percent, because of ice shear and storm removal. Similar levels are reported from other areas in New England and Canada.

This leads me to my conclusion that a certain amount of harvesting can be performed without jeopardizing the overall health of the ecosystem.

We have many serious environmental problems — global and local — and some definitely concern fisheries, but rockweed harvesting is not one of them. I implore fellow Mainers to devote their time and attention to issues that matter.

Susan H. Brawley is professor of botany at the University of Maine in the School of Marine Sciences.


Have feedback? Want to know more? Send us ideas for follow-up stories.

You may also like