History of Giant Kelp Harvesting in Tasmania
Interest in Tasmanian kelp beds as a possible commerical alginate
resources first began in the 1950s, with a major study undertaken
by teh CSIRO (between 1950-1952) to assess the quantities of Macrocystis
on the east coast. The CSIRO estimated a potential yield of approximately
35,000 to 40,000 tons of dry Macrocystis per year, based
on a recommended 3 harvests per year (Cribb 1954). Based on these
estimates, a commercial license to harvest kelp was first granted
in 1958 to Messers, Chegwiddon, Button and Kearns, in 1961 was
transferred to Alginates (Australia) Company. The harvesting operations
in Tasmania began in late 1963 with the alginate processing operations
based at Triabunna (Louisville).
The harvesting operations in Tasmania were essentially based on
the commerical harvesting methods in California. The kelp was
harvested to a depth of 3 feet by barges fitted with cutting blades
(which were pushed into the beds by tug boats). Under the original
license conditions, cutting operations were limited to 3 harvests
of the same bed each year (as recommended by the CSIRO), with
a fringe of kelp left around all beds harvested. Initially, no
harvesting was permitted during the lobster spawning season (15th
September to 15th December, each year).
Contrary
to the original estimates (35,000 to 40,000 tons per year), the
annual kelp harvested over the 8 years of harvesting, varied from
165 tons (dry weight) in 1965, to a maximum of 493 tons in 1969.
Further, the majority of offshore beds yielded only one crop or
harvest of kelp per year (not the originally estimated three).
In 1967 a new harvesting vessel was purchased by Alginates Australia,
the 'Alga’ to enable more of the coast to be harvested.
In 1971 Alginates applied for an extension of their lease area
for harvesting Macrocystis and to include Bull Kelp (Durvillaea
potatorum) on the grounds that not enough kelp was being harvested
to make a profit. At the same time extensions were made on the
'Alga' to increase its range. Early in 1973, Bull Kelp
was processed for the first time.
Dwindling
supplies of kelp became a major factor in the commerical viability
of the kelp processing plant. This was exacerbated by low prices
for alginates on the world market, and a couple of poor years
of harvesting. Late in 1973 the Alginates factory closed at Triabunna.
