1. Dr. Robin Hadlock Seeley with Dr. Sarah Hardy, Nancy Prentiss and Dr. Walter Adey published a new paper challenging an earlier paper (2023) claiming that rockweed recovers all its biomass one year after harvest. The new paper is Open Access, so you can read the full version here.


Johnston et al., 2023 (Bed-scale impact and recovery of a commercially important intertidal seaweed. J. Exp. Mar. Biol. Ecol. 561) report that rockweed biomass recovers to pre-harvest levels one year after commercial harvest.  The Johnston et al. study has two major problems in design, execution, and interpretation of results: 1)  industry partner conflict of interest and statistically undetectable impact of the harvest treatment on Ascophyllum nodosum (rockweed) beds, 2) incomplete statistical analysis with inappropriate inferential conclusions about biomass recovery of harvested rockweed beds.  Our analysis of their data shows that the only regions of the coast where rockweed biomass recovered to pre-harvest levels are the three regions where the harvest treatment was never detectable. In the one region where the harvest treatment was detectable, rockweed biomass did not recover to pre-harvest levels in a year.  Rockweed is a foundational species in the rocky intertidal food web as well as an ecosystem engineer. The improper interpretation by Johnston, et al. of the study data is misleading ecosystem managers and the public about the impacts of commercial rockweed harvests. Most concerning, this paper sets a false foundation for marine policy on commercial rockweed harvesting in Maine.

2. We are conducting a new multispectral drone intertidal survey of rockweed beds to further refine the ability of the drone to distinguish between intact rockweed (Ascophyllum), harvested rockweed (Ascophyllum), and Fucus. We are grateful for support of the Eastern Maine Conservation Initiative and an award from the Podell Endowment for Research and Scholarship at Cornell University. If you are interested in participating as a volunteer in this study (1 day TBD in Cobscook Bay), please contact us at

3.  MRC has two research interns starting work in June. One is supported by the Maine Geospatial Institute for a project developing an app for anyone to use to report rockweed harvest events, and create a GIS layer documenting the spatial pattern of rockweed harvest in Cobscook Bay. The other intern will be looking at mammal use of rockweed beds (otter video!).