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1、 公共英语80篇背诵阅读带翻译(十七)234 Raising Oysters In the past oysters were raised in much the same way as dirt farmers raised tomatoes - by transplanting them. First, farmers selected the oyster bed, cleared the bottom of old shells and other debris, then scattered clean shells about. Next, they “planted“ fert
2、ilized oyster eggs, which within two or 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 derive
3、d microscopic particles of food. Before long, farmers gathered the baby oysters, transplanted them in other waters to speed up their growth, then transplanted them once more into another body of water to fatten them up. Until recently the supply of wild oysters and those crudely farmed were more tha
4、n 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 vanished entirely. Fortunately, as far back as the early 1900”s marine biologists realized that if new measures were not taken, oyster
5、s would become extinct or at best a luxury food. So they set up well-equipped hatcheries and went to work. But they did not have the proper equipment or the skill to handle the eggs. They did not know when, what, and how to feed the larvae. And they knew little about the predators that attack and ea
6、t baby oysters by the millions. They failed, but they doggedly kept at it. Finally, in the 1940”s a significant breakthrough was made. The marine biologists discovered that by raising the temperature of the water, they could induce oysters to spawn not only in the summer but also in the fall, winter
7、, and spring. Later they developed a technique 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 flourished in water of different salinities and temperatures. In addition, the cult
8、ivated oysters tasted better! 饲养牡蛎 过去人们饲养牡蛎的方式很大程度上类似于田地里的农夫种植蕃茄-通过移植来饲养 它们。 首先，农夫选好牡蛎苗床，去除底部的旧壳和其它杂物，然后四处撒播洁净的壳。 接 着，他们“栽种“已受精的牡蛎卵。 这些卵在 23 周内会孵化成幼贝。 幼贝始终漂流直到 粘在苗床底部洁净的壳上为止。 它们会呆在那儿并渐渐长成小牡蛎。 我们称之为种子或贝苗。 贝苗吸进海水中的微小生物作为食物从而越长越大。 不久之后，农夫将这些小牡蛎收 集起来，把它们移种进其他的水域加快其生长，然后再次将它们移种进另外的水域以使其肥 壮起来。 直到最近，野生的以及人
9、工饲养的牡蛎完全能够满意人们的需要。 但是今日这种 可口的海味已不再大量存在。这个问题已经变得如此严峻以至于一些牡蛎苗床已完全消逝。 幸运的是，早在 20 世纪初期海洋生物学家们就意识到假如不实行新的措施，牡蛎将会灭亡 或至少会变为一种浪费的食品。 因此他们建筑了装备良好的孵卵场所并开头工作。 但是他 们尚没有适当的装置或技术来处理牡蛎卵。他们不知道何时、用什么以及如何喂养幼贝。他 们对捕食数百万幼小牡蛎的动物天敌也所知无几。 他们失败了，但他们坚韧地坚持了下来。 最终，在 20 世纪 40 年月，一个重要的突破性的进展产生了。 海洋生物学家发觉，上升水 温能够诱导牡蛎不仅在夏季也在秋季、冬季和春季里产卵。 后来他们进展了一项技术来喂 养幼贝至其长成贝苗。 他们进一步胜利地培育出了新的品种，可以反抗疾病、长得更快、更大并且在不同的盐度和温度的水中都能健壮生长.此外，这些培殖出的牡蛎口感更佳!
