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Introduction
Rockweed, Ascophyllum nodosum, is the dominant brown seaweed found intertidally along the coast of Nova Scotia. It is characterized by long (1-2m), strap-like fronds originating from holdfasts attached to the substrate, and conspicuous gas bladders that float the plant during high tides. In sheltered areas rockweed forms extensive beds, providing habitat for invertebrates and fishes during the tidal cycle. It takes approximately 2-5 years for rockweed to develop into fertile plants, and relative to other seaweeds, it has poor recruitment levels. Its dominance in the intertidal zone is believed to be the product of long-term succession from existing beds. Rockweed fronds can reach 15 years of age before breakage, and holdfasts, from which new fronds generate, can live for several decades.
Harvesting
Rockweed has been harvested commercially in Nova Scotia since the late 1950's and is currently the most important commercial seaweed in Atlantic Canada. Rockweed is processed for use as fertilizers, soil conditioners, and sources of micronutrients in animal feed supplement. Rockweed is also used as packing material when shipping live lobsters and marine bait worms. Additionally, it can be chemically processed to extract alginates, which are used in bulking, gelling, and stabilizing processes.
Presently, only hand harvesting of rockweed is allowed in Nova Scotia, with harvesting taking place in two manners. In areas with high tides, such as in St. Mary's Bay and the Annapolis Basin, harvesters use a hand held machete-like knife and work directly from the beach. In most other areas of the province, harvesters work from small boats using rakes which consist of a long handle attached to tongs and runners, with cutter blades approximately six inches above the tongs.
Management
Nova Scotia's rockweed resources are jointly managed by the Nova Scotia Fisheries and Aquaculture and Fisheries
and Oceans Canada (DFO). Since the late 1970s, the commercial rockweed harvest has been managed on an
area basis, with harvesting controls placed on small geographic units, or sectors, along the coast. The
province leases areas of the coast to companies and individuals, granting them exclusive commercial harvesting
rights within these areas. Leaseholders must submit annual management plans and harvest reports, pay lease
and royalty fees, and ensure that the rockweed harvesting regulations are followed. There are currently eighteen
rockweed leases in Nova Scotia, held by six leaseholders. All commercial rockweed harvesters must be registered
and licensed by DFO. In 2004 there were approximately 100 dedicated commercial harvesters during the summer
harvest season.
Current Status
After a period of decline following over-harvesting in the late 1980s and early 1990s, the commercial harvest has been steadily increasing.
Approximately 23,000 metric tonnes of rockweed were harvested in 2004, a 60% increase since 1998. The province continues to work closely with DFO,
leaseholders, and harvesters toward ensuring an ecologically sustainable harvest of rockweed for the benefit of all Nova Scotians.
For more information on rockwwed harvesting in Nova Scotia, contact Justin Huston, Coastal Zone Coordinator, at (902) 424-2996.
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