[解析]
(1)D.细节题.根据文章第三 段 But environmental damage and too much harvesting have cut the oyster population there.可知但是环境破坏和过多的捕鱼削减了那里的牡蛎种群.故选D.
(2)B.细节题.根据文章第 六段 But the restaurant no longer throws away all those shells.可知但餐厅不再扔掉所有这些贝壳.说明他们以前是要把贝壳扔掉的,故选B.
(3)A.细节题.根据文章倒数第 三段 In this way,the baby oysters can be raised until they have grown big enough to be moved to the Chesapeake.可知通过这种方式,可以饲养小牡蛎,直到它们长到足以移动到切萨皮克.故选A.
(4)A.主旨大意题.根据文章最后一段Their real goal is to try to restore healthy oysters to the Chesapeake Bay so that they can help restore a healthy Chesapeake Bay.可知他们的真正目标是尝试将健康的牡蛎恢复到切萨皮克湾,以便他们能够帮助恢复健康的切萨皮克湾.故选A.