Scientific publication (e.g., journal articles and book chapters independently peer-reviewed)
Sustainable seaweed cutting? The rockweed (Ascophyllum nodosum) industry of Maine and the Maritime Provinces
Unknown/not recorded
Is the species endemic HIDE
No
Population Status
Unknown/not recorded
No formal international protection in place
National Level
Formal national protection in place
ranked as a "high-priority” species for protection in the United States
Within the Cobscook Bay Rockweed Management Area,84 there is an annual limit (17%) on take (based on the available rockweed biomass);
Population Trend
Unknown/not recorded
Sub-national Level
Formal sub-national protection in place
Name
Emma Hemmerlé
Scientific Name
Ascophyllum nodosum
Common Name(s)
Norwegian Kelp
Knotted Kelp
Egg wrack
Bladderwrack
Rockweed
Type of Use
Extractive (i.e., the entire organism or parts of the organism are removed from its environment)
If extractive, for the target species, is this use
Non-Lethal
Does this use involve take/extraction of
Only parts or products of the organism (e.g., feathers, leaves, branches, eggs, nuts)
Details of parts/products taken
Rockweed clumps over 130 cm that are cut are typically reduced up to 55% of length (height) and 78% of biomass: i.e. a part of the stem is left when harvesting;
Are specific characteristics/traits being targeted?
Unknown/not recorded
Purpose of Use
Largescale commercial exploitation for trade
What is the main end use for any living organisms, parts or products taken/extracted?
The dearth of impact assessment, combined with the tendency of state and provincial governments to allow rockweed harvests unless and until negative impact information is available, has produced a situation in which rockweed harvests are intensifying even though critical scientific information is lacking
Is the use part of a strategy to generate conservation incentives, to finance conservation, or to improve tolerance/stewardship?
Unknown/not recorded
Is there evidence that the use is affecting the conservation status of the species? HIDE
Yes – use is negatively affecting the status (e.g., population is declining; extraction effort is increasing)
Is there evidence that the use is affecting natural selection?
Unknown/not recorded
Is there evidence that the use is affecting poaching of illegal wildlife trade?
Unknown/not reported
Is there any evidence that this use of the species is having a knock-on effect on the status of non-target species
Yes, it is having a negative effect (e.g., prey depletion, stress, disrupted breeding, movement, sleeping, feeding patterns)
Yes, negative (e.g., it destroys/ degrades it due to over-use)
Additional Details (if available)
Indirect impacts of rockweed harvesting on com- mon eider (Somateria mollissima) ducklings stem from duckling feeding behavior. For about three weeks, ducklings are unable to dive for mussels and must forage in the floating rockweed canopy (for small prey such as amphipods8). During this time, ducklings are vulnerable to predation by bald ea- gles and great black backed gulls;
Impacts of simulated rockweed cutting were investigated in Maine and resulted in overall species richness declined and did not recover during the two-year study.
Rockweed cutting also significantly affected abundance of common intertidal species: green crabs (Carcinus meanas), common periwinkles (L. littorea), blue mussels (Mytilus edulis), limpets (Tectura testudinalis), a colonial hydroid (Dynamena pumila), blue mussel spat (M. edulis recruits), and barnacles (Semibalanus balanoides).
Additional Details (if available)
Rockweed harvesting can also result in a loss of habitat complexity, since the most complex part of the clump in the canopy is removed.
Details of assessment carried out
Until sustainable levels of cutting and appropriate regulations are identified, commercial-scale rockweed cutting presents a risk to coastal ecosystems and the human communities that depend on those ecosystems.
In addition to problems defining a ecologically sustainable level of rockweed harvest and the challenge of understanding cumulative impacts on a
landscape scale, there are three further difficulties in assessing an ecologically sustainable level of harvest: a complex web of interactions in a diverse rockweed community harvest impact assessments; the rockweed community (vertebrates, invertebrates, algae) varies in space and time, creating site- and time- specific impacts, and high-power statistical tests of impact will require large sample sizes or long- term studies, or both.The challenges described above result in a lack of adequate measures of the full impact of rock- weed harvesting. The current metric for“sustainable”harvests— MSY—is inappropriately narrow.
Has a valuation of financial flows from this use at the site/national/international level been recorded
Seeley, R. H., & Schlesinger, W. H. (2012). Sustainable seaweed cutting? The rockweed (Ascophyllum nodosum) industry of Maine and the Maritime Provinces. Annals of the New York Academy of Sciences, 1249, 84–103. https://doi.org/10.1111/j.1749-6632.2012.06443.x
Fegley noted that full recovery of Ascophyllum had not occurred even two years after cutting: cut rockweed was significantly shorter.