Commerical Giant Kelp Harvesting
Giant Kelp (like other kelps) also have a capacity for some of
the most remarkable growth rates in the plant kingdom - in southern
California, Macrocystis plants can grow up to 50cm a day. These
extraordinary growth rates, and their known industrial and pharmaceutical
benefits, have resulted in the world-wide commercial harvesting
and exploitation of Giant Kelp forests both, in Tasmania (eg.
east coast) and overseas (eg. California). In the USA, M.pyrifera
is harvested from large offshore beds off the coasts of California
and Mexico. Some 120,000 tonnes wet weight are gathered each year
using ships equipped with cutting machinery.
The
first use of Giant Kelp on a large commercial basis was in California,
for the purpose of producing potash (potassium carbonate) during
the First World War. At the time, potash was a necessary ingredient
in the production of gunpowder. The potash was derived from the
kelp ashes after it had been burned. At that time, kelp was harvested
by encircling a stand of kelp with a cable and then pulling on
the cable. This generally had the effect of ripping out the entire
kelp plant, including the holdfast. By comparison, today's harvest
methods are limited to cropping the fronds, which are short-lived
compared to the holdfast.
Kelp
that is harvested in California today is primarily used in chemical
industrial applications. Algin, which is a product derived from
kelp, is used as an emulsifier in processed foods and other products
where a smooth texture is required (eg. paints, cosmetics, pharmaceuticals).
Other uses of kelp are as food for cultured abalone, and as substrate
for the herring-roe-on-kelp fishery (exported for Sushi).
Alginates
are cell-wall constituents of brown algae (Phaeophyta). Alginates
of one kind or another seem to be present in most species of brown
algae but they occur in exploitable quantities (30-45% dry weight)
only in the larger kelps and wracks (Laminariales and Fucales).
Alginates are extracted chemically and used in bulking, gelling,
and stabilizing processes. Products using alginates include charcoal
briquettes, cosmetics, ceramics, cheese, paint, asphalt, rubber
tires, polishes, toothpaste, ice cream, and paper. About 25,000
tonnes of alginic acid per annum are extracted world-wide. The
main producers are Scotland, Norway, China and the USA, with smaller
amounts being produced in China, Japan, Chile, France and Spain.
Check out the following websites for further information on the
uses of alginates and Giant Kelp:
