Marine biologists have noticed that whale shark numbers have been falling in recent years.
But the scientists have not known exactly why.
A new international study suggests that collisions with shipping traffic could be a major reason for the decrease.
The study was led by the Marine Biological Association of the U.K. and the University of Southampton, along with experts in Australia and New Zealand.
The study appeared in the publication Proceedings of the National Academy of Sciences.
Researchers examined satellite data to observe about 350 whale sharks.
They found that the world's largest fish spend most of their time in waters used by large shipping boats.
The study showed that information from the devices used to observe their movements often ended in busy shipping paths.
The researchers believe many sharks are probably being hit and killed by boats before sinking to the ocean floor.
Mark Erdmann is with the University of Auckland in New Zealand and a scientist at the non-profit environmental organization Conservation International.
He was one of the writers of the new study.
Erdmann believes shipping is a major threat to whale shark populations.
"…What the study found is that, indeed, there is a tremendous amount of overlap between where whale sharks are moving and global shipping traffic. So, those are real collision-risk areas," he said.
Whale sharks can grow up to 20 meters long.
They play an important part in providing healthy ocean environments.
Most deadly strikes between whale sharks and boats are likely to go unobserved or unreported.
There are currently no laws to protect whale sharks against these kinds of collisions.
翻译：
海洋生物学家指出，近年来鲸鲨总数一直在下降。
但科学家们并不知道确切的原因。
一项新的国际研究表明，与船舶的碰撞可能是鲸鲨数量减少的主要原因。
该研究由英国海洋生物协会、南安普顿大学、澳大利亚和新西兰的专家领导。
研究发表在《美国国家科学院杂志》上。
通过卫星数据，研究人员观察了大约350头鲸鲨。
他们发现，世界上最大的鱼大部分时间都在大型运输船经过的水域活动。
研究表明，用于观察其活动的机器提供的信息通常会停止在繁忙的路线上。
研究人员认为，许多鲨鱼在被船碰撞后可能会死亡，然后沉入海底。
马克·厄德曼在新西兰奥克兰大学工作，也是非营利环境组织保护国际的科学家。
他是这项新研究的作者之一。
厄德曼认为，船只是对鲸鲨数量的主要威胁。
他说：“……研究发现，鲸鲨的活动范围实际上与全球船舶的出航区域重叠。因此，这些都是真正有碰撞危险的区域”。
鲸鲨可接近20米。
它们在提供健康的海洋环境方面发挥着重要作用。
鲸鲨和船舶之间的大多数致命袭击可能不会被发现或报道。
没有法律保护鲸鲨免受此类碰撞。