然而，不幸的是，自从17世纪以来，由于捕鲸的高额利润，捕鲸者对白鲸进行了疯狂的捕杀，致使白鲸数量锐减。更加可悲的是白鲸的生态环境遭到毁灭性的破坏，一批批白鲸相继死亡。科学家们经过尸体解剖才找到了引起死亡的因素：由于受到一系列有毒物质的侵害，使其免疫系统遭到严重的破坏，这些白鲸患上了胃溃疡穿孔、肝炎、肺脓肿等疾病；更有甚者，有的白鲸患了膀胱癌，这在鲸类动物中真是闻所未闻的。
However, unfortunately, since the 17th century, because of the great amount of profit going whaling, whalers have carried on crazy hunting to the beluga , cause beluga's quantity to fall sharply. The more sad one is that the ecological environment of the beluga suffers crushing destruction, batches of belugas die in succession. The scientists have dissected and just found the factor which cause the death through the corpse : Encroached on by a series of noxious substances , make its immune system suffer serious destruction, these belugas suffer from diseases , such as gastric ulcer boring a hole , hepatitis , lung abscess ,etc.; What is more, some belugas have suffered from the bladder cancer, this was really had never heard of in cetacean's animal.
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