In the oysters were raised in much t。he same way as。 dirt farmer。s raised tomatoes- by transplanting them. First, farmers selected the oyster bed, cleared the。 b。ottom of old sh。ells and other debris, then scatt。ered clean sh。ells about. N。ext, they "planted" fertilized oyster eggs, wh。i。ch within two o。r three weeks hatched into larvae. The larvae drifted until they attached themselves to the clean shells on。 the bottom. There they remained and。 in time grew into baby。 oysters called seed or spat. The spat grew larger by drawing in seawater from which they derived microscopic particles of food. Before long, farmers gath。ered the baby oysters, transplanted them once more into another body of water to fatten。 them up.
Until recently the supply of wild oysters and tho。se crudely farmed were more than enough to satisfy people's needs. But today the delectable seafood is no longer available in abundance. The problem has become so serious that some oyster beds。 have van。ished entirely.
Fortunately, as far back as the ea。rly 1900's marine biologists realized that if new measures were not taken, oysters would become extinct or at。 best a luxury。 food. So they set up well-equipped hatcheries and went to work. But they did not ha。ve the proper equipment。 or the skill to handle the eggs. Th。ey。 did not know when, what, and how to feed t。he l。arvae. And they knew little about the predators that attack and eat baby oysters by the millions. They failed, but they doggedly kept at it. Finally, in the 1940's a significant breakthr。ough was made.
The marine biologists discovered that by raising the temperature of the water, they could induce oy。sters to spawn not only in the summe。r but also in the fall, winter, and spring. Later they developed a tech。nique for feeding the larvae and rearing them to spat. Going still further。, they succeeded in breeding new strains that were resistant to diseases, grew faster and larger, and fl。ouri。shed in water of different salinities and temperatures. In addition
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