拯救鲨鱼的绿光

Science & Technology

科技版块

Marine conservation

保护海洋环境

A green light for saving sharks

拯救鲨鱼的绿光

Illuminating fishing nets may reduce by-catch

照亮渔网会减少捕获量

Small-scale fisheries supply many people with food.

小型渔业为许多人提供食物。

Almost all of those who ply them rely on gillnets to trap their prey.

几乎所有捕食者都依靠刺网诱捕猎物。

But gillnets trap other things, besides: endangered animals such as turtles; dangerous ones, such as Humboldt squid; and ones that are both endangered and dangerous, such as several types of shark.

但是刺网还能捕捉其他东西，比如濒危动物——海龟；危险的，如洪堡乌贼；还有既濒危又危险的物种，比如几种鲨鱼。

Everyone involved would be better off if this did not happen.

如果这种情况不发生，参与其中的每个人都会过得更好。

Building on studies done both by himself and by others, to try to avoid the accidental netting of turtles, Jesse Senko, a marine-conservation biologist at Arizona State University, has been investigating the idea of fitting light-emitting diodes (leds) to nets to ward off other unwanted by-catch without discouraging target animals from entangling themselves.

亚利桑那州立大学(Arizona State University)的海洋保护生物学家杰西·森科(Jesse Senko)在自己和其他人所做研究的基础上，试图避免意外捕获海龟，他一直在研究将发光二极管安装到渔网上的想法，可以缠住目标猎物的同时又能避开其他不想要的猎物。

And, as he reports in Current Biology, it seems to work.

而且，正如他在《当代生物学》上所报道的那样，这似乎奏效了。

His particular concern was for the safety of elasmobranchs, as sharks, rays and skates are called collectively.

他特别担心的是板鳃鱼的安全，板鳃鱼是鲨鱼、魟鱼和鳐鱼的统称。

While sharks are better known for their sensitive nostrils than their keen eyesight—some species famously being able to smell traces of blood in vast quantities of water—many have acute vision, too.

与敏锐的视力相比，鲨鱼更为人所知的是它们灵敏的鼻孔，——一些鲨鱼以能够在大量水中闻到血迹而闻名，不过许多鲨鱼也有敏锐的视力。

And, though colloquially referred to as "fish", elasmobranchs are actually less closely related to teleosts (the bony fish that predominate on most fishmongers’ slabs) than turtles are, so their visual systems might easily be as different.

虽然俗称为“鱼”，但板鳃鱼与硬骨鱼（硬骨鱼在大多数鱼贩的鱼板上占多数）的亲缘关系实际上不如海龟，所以它们的视觉系统很可能与海龟一样不同。

It thus seemed worthwhile checking to see whether the trick that worked with turtles would work with sharks.

因此，似乎值得试一试，看看对海龟有效的方法是否对鲨鱼也有效。

Dr Senko and his colleagues therefore set up an experiment in the Gulf of Ulloa, off the coast of Baja California, in Mexico, in which they collaborated with local fisherfolk to deploy over 10,000 metres of nets that had had battery-powered waterproof green leds clipped onto them at ten metre intervals.

因此，森科博士和他的同事们在墨西哥加利福尼亚州海岸外的乌洛亚湾进行了一项实验，他们与当地渔民合作，部署了超过1万米的渔网，这些渔网上每隔10米就夹着电池供电的防水绿色发光二极管。

(Green leds are more efficient than those of other colours, and their light better penetrates seawater.)

（绿色发光二极管比其他颜色的发光二极管效率更高，而且它们的光更能穿透海水。）

In half of the nets these lights were illuminated.

渔网中的二极管，一半被照亮。

The other half were left unlit, as controls.

另一半作为对照，没有点亮。

Each lit net was paired with an unlit one, and the two were deployed alongside one another at prime fishing locations.

每个发光的网与一个不发光的网作对照，这两个网并排部署在主要的捕鱼地点。

The fishers' targets were Californian halibut and large groupers.

渔民的目标是加利福尼亚的大比目鱼和大型石斑鱼。

Dr Senko was interested both in what else got caught and whether the lights decreased catches of the target species.

森科博士感兴趣的是除此之外还捕捉到了什么，以及灯光是否减少了对目标物种的捕获量。

On the latter point, reassuringly, they did not.

在后一点上，令人放心的是，并没有减少捕获量。

On the former, the lit nets caught 95% fewer kilograms of sharks, rays and skates.

关于前者，点燃的渔网捕获的鲨鱼、魟鱼和鳐鱼数量减少了95%。

In particular, several threatened species, including Munk’s devil ray (pictured) and the diamond stingray, turned up less often in the illuminated than the unilluminated nets.

特别值得一提的是一些濒危物种，包括芒克魔鬼鱼和钻石黄貂鱼，在有照明的渔网中出现的频率低于没有照明的渔网。

Humboldt squid were also discouraged.

洪堡乌贼出现的频率也低了。

(Cephalopods, the group of molluscs to which they belong, are also well known for their acute eyesight.)

（头足类是软体动物的一种，它们也以敏锐的视力而闻名。）

The advantage from the point of view of fisherfolk was that they needed to spend a lot less time clearing these hostile by-catches from their nets.

从渔民的角度来看，这样做的好处是，他们可以花更少的时间从渔网中清除这些有害的副渔获物。

And, crucially, the leds concerned are cheap, robust and easy to fit.

而且至关重要的是，用到的发光二极管价格便宜，坚固耐用，易于安装。

There are also plans to make them solar powered, for easy recharging.

为了方便充电，还计划让它们使用太阳能。

Here, then, is a conservation idea from which everyone wins.

这就是一个人人都能从中受益的环保理念。