SECTION 4

Good afternoon everyone.

下午好，各位。

Well, with some of you about to go out on field work, it's timely that in this afternoon's session I'll be sharing some ideas about the reasons why groups of whales and dolphins sometimes swim ashore from the sea right onto the beach and, most often, die in what are known as 'mass strandings'.

因为你们中的一些人就会前往实地考察，是时候在这个下午的课程中 我来跟大家分享一些事儿，关于为什么一群群的鲸鱼和海豚有时会从海里游上岸，并且时常死亡，为我们所说的“集体搁浅”。

Unfortunately, this type of event is a frequent occurrence in some of the locations that you'll be travelling to, where sometimes the tide goes out suddenly, confusing the animals.

不幸的是，这种类型的事件经常发生在你即将前往的地方，有时，那里的潮汐突然退去会使动物感到困惑。

However, there are many other theories about the causes of mass strandings.

但是，关于“集体搁浅”的原因还有一些其他理论说法。

The first is that the behaviour is linked to parasites.

第一个理论认为这种行为与寄生虫有关。

It's often found that stranded animals were infested with large numbers of parasites.

经常发现搁浅的动物受到大量寄生虫的感染。

For instance, a type of worm is commonly found in the ears of dead whales.

比如说，在死去的鲸鱼耳朵中常常会发现一种蠕虫。

Since marine animals rely heavily on their hearing to navigate, this type of infestation has the potential to be very harmful.

因为海洋动物非常依赖它们的听觉来导航，这种侵扰有可能是非常有害的！

Another theory is related to toxins, or poisons.

另一个理论是与毒素有关，或毒药。

These have also been found to contribute to the death of many marine animals.

很多海洋动物的死亡都被发现有这样的因素。

Many toxins, as I'm sure you're aware, originate from plants, or animals.

很多毒，我相信你们都知道，源于植物，或动物。

The whale ingests these toxins in its normal feeding behaviour but whether these poisons directly or indirectly lead to stranding and death, seems to depend upon the toxin involved.

鲸鱼在正常的喂养行为中摄取这些毒素，但这些有毒物质是否直接或间接导致搁浅死亡，似乎取决于涉及的毒素。

In 1988, for example, fourteen humpback whales examined after stranding along the beaches of Cape Cod were found to have been poisoned after eating tuna that contained saxitoxin, the same toxin that can be fatal in humans.

例如在1988年，十四头座头鲸沿科德角海滩搁浅后被检查出在食用含有蛤蚌的金枪鱼后中毒，同样的毒素，能致人死亡。

Alternatively, it has also been suggested that some animals strand accidentally by following their prey ashore in the confusion of the chase.

另外，也有人提出一些动物意外地跟随自己的猎物上岸后搁浅。

In 1995 David Thurston monitored pilot whales that beached after following squid ashore.

在1995年戴维.瑟斯顿发现领航鲸跟随鱿鱼上岸后搁浅。

However, this idea does not seem to hold true for the majority of mass strandings because examination of the animals' stomach contents reveal that most had not been feeding as they stranded.

然而，这一想法似乎并不适用于大多数大规模搁浅，因为动物胃内容物的检查表明，大多数搁浅动物并未进食。

There are also some new theories which link strandings to humans.

也有一些新的理论将搁浅与人联系起来。

A growing concern is that loud noises in the ocean cause strandings.

日益增加关注的是海洋中的噪音造成搁浅。

Noises such as those caused by military exercises are of particular concern and have been pinpointed as the cause of some strandings of late.

比如那些由军事演习引起的噪声特别受到关注，已被认定为是一些搁浅的原因。

One of these, a mass stranding of whales in 2000 in the Bahamas coincided closely with experiments using a new submarine detection system.

其中，在2000年巴哈马集体搁浅的鲸鱼与使用新的潜艇探测系统实验吻合。

There were several factors that made this stranding stand out as different from previous strandings.

有几个因素使这次搁浅与以往的搁浅有所不同。

This led researchers to look for a new cause.

这引导研究人员寻找新的原因。

For one, all the stranded animals were healthy.

一方面，所有搁浅的动物身体都很健康。

In addition, the animals were spread out along 38 kilometres of coast, whereas it's more common for the animals to be found in a group when mass strandings occur.

此外，动物分散在38英里的海岸线上，然而更常见的搁浅情况一般都是集体性的。

A final theory is related to group behaviour, and suggests that sea mammals cannot distinguish between sick and healthy leaders and will follow sick leaders, even to an inevitable death.

最后一个理论是与群体行为有关的，海洋哺乳动物不能区分生病和健康的领导者，并会跟随生病的领导者，即使是导致一场不可避免的死亡。

This is a particularly interesting theory since the whales that are thought to be most social - the toothed whales - are the group that strand the most frequently.

这是一个特别有趣的理论，因为鲸鱼被认为是最具社会性的、有牙齿的鲸鱼，是最经常搁浅的群体。

The theory is also supported by evidence from a dolphin stranding in 1994.

这个理论也同样被1994年海豚搁浅的证据所支持。

Examination of the dead animals revealed that apart from the leader, all the others had been healthy at the time of their death.

死亡动物的检查显示，除了领导者，所有其他的在他们的死亡时间都是健康的。

Without one consistent theory however it is very hard for us to do anything about this phenomenon except to assist animals where and when we can.

如果没有一致的理论，我们很难对这种现象做任何事情，除了随时随地帮助动物。

Stranding networks have been established around the world to aid in rescuing animals and collecting samples from those that could not be helped.

搁浅网络已在世界各地建立了，去帮助抢救动物，并从那些不可能帮助的动物身上采集样本。

I recommend John Connor's Marine Mammals Ashore as an excellent starting point if you're interested in finding out more about these networks, or establishing one yourself.

如果你们有兴趣找到更多这方面的网络或建立自己的网络，我建议约翰·康纳的《海洋哺乳动物上岸》可以作为一个很好的起点。