62
The Last Resource
attain a marketable size in about half the normal time. One American
oyster producer claims that hanging cultivation can produce about
64,000 pounds of oyster per acre—several times the traditional
harvest.
Hanging cultivation has already helped another shell sh industry
to prosperity. Mussels are reared in large quantities from rafts
moored in the shelter of the fjord-like ‘rias’ which cut into the
coastline of the province of Galicia in North—western Spain. The
industry started in 1946 when Manuel Trig0 introduced the rst
rafts to the Ria Arosa. Since then the industry has expanded rapidly
until now about I, 500 rafts produce over 75,000 tons of mussels per
year. The rafts carry a framework from which bang esparto grass
ropes spaced two feet apart. On average each raft carries 800 ropes
from sixteen to twenty feet long according to the depth of the moor—
ing. The ropes are changed several times through the life of the
mussel from seed mussel (one twentieth of an inch) to market
mussel (three inches). Each time the shell sh have to be removed
from the rope, to which they become attached by thread—like
secretions called byssus threads, and tied to the new one by hand.
The mussels take from nine to fourteen months to reach a market—
able size.
The Spanish system eontrasts sharply with the mechanization of
the mussel industry in the Netherlands—the major mussel producer
in Europe. The Dutch use boats and mechanical dredges to move
the growing mussels from one area to another just as the Spanish
growers of Galicia transfer them from one r0pe to another. Wild
seed mussels settle rst in dense patches in the Waddensee; from
there they are moved to nursery and then to fattening areas. With
their large boats pulling several dredges at once, the Dutch can
handle colossal quantities of mussels in a rapid, economical manner
—a single boat can pick up as many as 40 tons of the shell sh in an
hour. Similar reliance on mechanical power is found in the soft clam
(Mya arenariæ) shery in the Chesapeake Bay area. The Americans
use powerful hydraulic dredges to reach the shell sh which lie
buried in the sand and mud.
But the cultivation of bivalves like clams, mussels and 0ysters does
not end when they are gathered; the animals must be cleansed of
possible harmful contaminants before they are sent to market. These
shell sh feed by ltering out small particles, largely phytoplankton,
from the water drawn into the gil] cavity during respiration. The
The Last Resource
attain a marketable size in about half the normal time. One American
oyster producer claims that hanging cultivation can produce about
64,000 pounds of oyster per acre—several times the traditional
harvest.
Hanging cultivation has already helped another shell sh industry
to prosperity. Mussels are reared in large quantities from rafts
moored in the shelter of the fjord-like ‘rias’ which cut into the
coastline of the province of Galicia in North—western Spain. The
industry started in 1946 when Manuel Trig0 introduced the rst
rafts to the Ria Arosa. Since then the industry has expanded rapidly
until now about I, 500 rafts produce over 75,000 tons of mussels per
year. The rafts carry a framework from which bang esparto grass
ropes spaced two feet apart. On average each raft carries 800 ropes
from sixteen to twenty feet long according to the depth of the moor—
ing. The ropes are changed several times through the life of the
mussel from seed mussel (one twentieth of an inch) to market
mussel (three inches). Each time the shell sh have to be removed
from the rope, to which they become attached by thread—like
secretions called byssus threads, and tied to the new one by hand.
The mussels take from nine to fourteen months to reach a market—
able size.
The Spanish system eontrasts sharply with the mechanization of
the mussel industry in the Netherlands—the major mussel producer
in Europe. The Dutch use boats and mechanical dredges to move
the growing mussels from one area to another just as the Spanish
growers of Galicia transfer them from one r0pe to another. Wild
seed mussels settle rst in dense patches in the Waddensee; from
there they are moved to nursery and then to fattening areas. With
their large boats pulling several dredges at once, the Dutch can
handle colossal quantities of mussels in a rapid, economical manner
—a single boat can pick up as many as 40 tons of the shell sh in an
hour. Similar reliance on mechanical power is found in the soft clam
(Mya arenariæ) shery in the Chesapeake Bay area. The Americans
use powerful hydraulic dredges to reach the shell sh which lie
buried in the sand and mud.
But the cultivation of bivalves like clams, mussels and 0ysters does
not end when they are gathered; the animals must be cleansed of
possible harmful contaminants before they are sent to market. These
shell sh feed by ltering out small particles, largely phytoplankton,
from the water drawn into the gil] cavity during respiration. The