DV-16-13 Assessing the ecological and economic impacts of Chondrus crispus: the rise of Maine’s new foundation species

Robert Steneck
University of Maine School of Marine Sciences

Thew Suskiewicz
Université Laval

Filippo Ferrario
Université Laval

Doug Rasher
University of Maine

Maine’s coastal ecosystem changed profoundly during the 1990s, with the collapse of nearshore sea urchin populations. The loss of this important grazer led to increased abundance of Irish moss (Chondrus crispus), kelp and other macroalage throughout the Gulf of Maine. State agencies monitor the approximate coverage of macroalgae (seaweeds) in the subtidal zone, however the surveys are coarse in scale and don’t include measures of individual species. Yet not all seaweeds are equal in terms of their value to humans or role in the ecosystem. Many algal species provide vital habitat and can influence ecological interactions between benthic organisms. The bushy red alga Chondrus crispus has a specific architecture that is ideal habitat for tiny and juvenile crustaceans such as Jonah crab. Researchers aim to quantify algal biomass and species composition along the coast of Maine, building on a previous survey they conducted in 2004 and leveraging current efforts by state agencies.

Researcher divers are using a photo-mosaic technique, photographing transects within survey sites and then analyzing the images in the lab. This greatly increases the speed and spatial coverage of the survey effort, allowing a detailed taxonomic survey to be conducted in a single season. Information on the distribution and abundance of seaweed species and the role of these seaweeds in their natural environment will be shared with state agencies to inform management practices for Maine’s growing seaweed harvesting industry.

Sea Grant funds $5,391


“Kelps in hot water,” Salarius, August 2016
“Return of the seaweed,” The Working Waterfront, November 2016