科学美国人60秒 SSS 年轻大白鲨吃底栖鱼类（在线收听）

This is Scientific American's 60-second Science, I'm JasonGoldman.

这里是科学美国人——60秒科学系列，我是杰森·古德曼。

The image of a dorsal fin cutting through the sea surface is iconic.

背鳍划破海面是种标志性画面。

But scientists studying the stomach contents of young great white sharks off the coast of Australia were in for a surprise

但是，研究澳大利亚沿海年轻大白鲨胃内容物的科学家，

when they learned that the predators seem to spend a lot of time patrolling the seafloor.

在发现这种食肉动物似乎花大量时间在海底巡游时，还是大吃了一惊。

"They have a predominantly fish-based diet, which is not unexpected for juvenile white sharks.

“它们的食物以鱼类为主，这对幼年大白鲨来说不足为奇。

The most important prey species we identified was eastern Australian salmon."

我们此前识别出的最重要猎物种类是东澳大利亚三文鱼。”

University of Sydney graduate student Richard Grainger.

悉尼大学研究生理查德·格兰杰说到。

He and his team sorted through the stomach contents of more than 50 juvenile white sharks

他和团队将50多只幼年大白鲨的胃内容物进行了分类，

that died after being entangled in shark exclusion nets meant to protect swimmers.

这些大白鲨因被用来保护游泳者的防鲨网缠住而死亡。

"The overall unexpected finding was just the diversity and importance of bottom-dwelling fishes.

“全部出乎意料的发现是，底栖鱼类的多样性和重要性。

Things like stargazers—which bury themselves in the sand, they're quite strange-looking fish—and flathead but also stingrays."

比如将自已埋进沙子的胆星科鱼，它们的外表非常奇怪，还有鲬科鱼和黄貂鱼。”

People actually did not have a good idea of the particulars of great white shark diets.

人们其实并不太了解大白鲨饮食的特殊性。

As Grainger points out, the sharks enjoy protections throughout the world.

正如格兰杰所指出，大白鲨享受着世界各地的保护。

So most researchers estimated their diets through the chemical markers that they can ethically access by taking small skin samples.

因此，大多数研究人员通过化学标志物来估计大白鲨的饮食，这些化学标志物可以从小块皮肤样本上道德地获取。

These measurements indicate at what level of the food chain the predator is feeding but not the actual critters that make up their meals.

这些测量结果显示的是这种食肉动物在食物链的哪个层次进食，而不是其饮食由哪些实际生物组成。

"There's quite a lot of evidence that lots of different animals,

“有相当多的证据表明，它们吃许多不同的动物，

so even carnivores, omnivores, herbivores self-select different prey or food based on a particular balance of nutrients."

有食肉动物、杂食动物、草食动物，也会根据特定营养平衡自行选择不同的猎物或食物。”

Grainger hopes that by further understanding what juvenile white sharks like to eat,

格兰杰希望，通过进一步了解幼年大白鲨喜欢的食物，

he can begin to piece together how and why they make their predatory choices.

他可以开始拼凑出它们做出捕食选择的方式和原因。

The study was published in the journal Frontiers in Marine Science.

这项研究发表在《海洋科学前沿》期刊上。

"Understanding and predicting when sharks might be more abundant in certain areas would be an ultimate end goal."

“最终目标是，了解和预测大白鲨在某些地区何时会数量更为丰富。”

Avoiding or mitigating human-shark conflicts means understanding the sharks' nutritional goals.

避免或缓解人类与鲨鱼的冲突，意味着了解鲨鱼的营养目标。

And if researchers can anticipate where and when sharks are likely to spend their time hunting,

如果研究人员能够预测鲨鱼可能在何时何地捕食，

they can better protect humans from getting bitten—and sharks from getting killed.

他们就能更好地保护人类不被咬伤，同时保护鲨鱼不被杀死。

Thanks for listening for Scientific American's 60-second Science. I'm Jason Goldman.

谢谢大家收听科学美国人——60秒科学。我是杰森·古德曼。