The Canadian province of Nova Scotia does not allow mechanical cutting of rockweed in part because of the threat of habitat damage1. Annapolis Basin, St. Mary’s Bay, and Lobster Bay [NS] showed signs of overharvesting rockweed as recently as 2006. (Ref)
How does a mechanical cutter work?
"A reciprocating cutter blade cuts a 2.4 m swath; shoots are picked up by a conveyor belt and moved into a 1.4 t capacity storage bay." (Ref)
How much rockweed can a mechanical cutter take per day?
Mechanical cutters are capable of removing up to 50 tons of rockweed a day (Nova Scotia Department of Fisheries).
1"[Nova Scotia] rejects any mechanical harvest method similar to those used in NS in the past, arguing that this would reduce employment and could produce a negative habitat impact." (Ref)
"The still-dripping seaweed [rockweed cut in Maine] is then loaded on conveyor belts, where the snails, periwinkles, and other creatures on it are shaken loose and disposed of." ~ from a 2005 article in Spa Finder