研究称蚊帐被广泛用于捕鱼

Mosquito Nets Widely Used for Fishing, Study Finds

Mosquito nets usually are used to prevent the spread of diseases which are passed by mosquito bites. Those treated with insect killing¹ substance have been especially successful in the fight to against malaria². But, nets now are also being used for catching³ fish in many tropical areas, a new study says.

The nets’ effectiveness is worrying some experts about possible harm to fish populations.

The study was published by the free online journal PLOS ONE. The study’s writers say poverty is the main reason for mosquito net fishing. They say efforts to limit use of the method might hurt people who live on the edge of survival⁴.

Catching many fish in many places

Insecticide-treated mosquito nets are used to cover the place in which a person sleeps to prevent mosquitos from biting them.

The nets are provided widely, often at low-cost or even free. The World Health Organization says access to the nets helped reach a drop in malaria deaths. The WHO found a 60 percent reduction from 2000 to 2015. More than 150 million nets were given to countries where malaria exists in 2015.

Rebecca Short is the lead investigator⁵ of the new research. She is studying for her doctorate⁶ in the ocean resources field at Imperial⁷ College London. Short is based in Mozambique. She says she sees many people there using insecticide treated nets to fish.

Fishing this way is easy and low cost. But, this could result in higher numbers of fishermen and decreasing numbers of an already limited supply of fish.

Short and her coworkers did a small online study to learn about the size of the issue. They gave the survey to conservation, health and development workers worldwide.

Nearly 100 people, from Senegal to Samoa, reported seeing mosquito-net fishing.

"I don't think even we expected to get the results that we did," Short says. "Pretty much everywhere that malaria's a risk, there's people fishing with these nets."

Some of the time the fishing was simple, and would just involve, "A couple people dragging a net through the water," Short says. She said the small-scale net fishing can provide a good source of protein and money without serious problems. She also said this can be good for women, who are often prevented from doing more profitable⁸ work.

However, the researchers found wider, and more damaging, use of mosquito nets elsewhere. The study describes cases, as in Bangladesh, where fishermen blocked entire river spans⁹ with mosquito nets.

In these cases, Short says, "Obviously, absolutely nothing gets through.”

Conflicting results

Fishing with mosquito nets is illegal in many places to keep the fish population safe. But Short is not sure that is the best way to control the method.

"There's huge issues with enforcement," she says. "Do you put a mother who's trying to feed her kids in prison for three years just for using a mosquito net to fish with?"

Tim McClanahan is a reef¹⁰ scientist with the Wildlife Conservation Society. He has questioned the benefits mosquito-net fishers are reportedly gaining.

He says many people believe that, "because the poor and women are doing it, it is improving their food security.” However, his research has found that is not always true.

Fishery management methods include catching larger, full-grown fish that have had time to produce children.

But, Rebecca Short’s study discusses a debated method called “balanced harvest.” In this method, fishers try to catch fish of all sizes, based on the numbers in their population. Since mosquito nets catch everything, the authors note, they may be helping¹¹.

McClanahan disagrees. He says this idea is “somewhere between wrong and dangerous." The harvest from mosquito nets is not balanced, he said.

Short agrees that the issue needs more study. She says researchers need to know the exact effect mosquito net fishing is having on fish populations. And she says they need better local understanding of why people are doing it.

I’m Phil Dierking.

Words in This Story

access - n. a way of being able to use or get something

conservation - n. the protection of animals, plants, and natural resources?

insecticide - n. a chemical substance that is used to kill insects?

mosquito net - n. a net that is placed over something (such as a bed) in order to keep out mosquitoes?

subsidize - v. to help someone or something pay for the costs of (something)?

tropical - n. of, relating to, occurring in, or used in the tropics

1 killing   

n.巨额利润；突然赚大钱，发大财

参考例句：

• Investors are set to make a killing from the sell-off.投资者准备清仓以便大赚一笔。
• Last week my brother made a killing on Wall Street.上个周我兄弟在华尔街赚了一大笔。

2 malaria   

n.疟疾

参考例句：

• He had frequent attacks of malaria.他常患疟疾。
• Malaria is a kind of serious malady.疟疾是一种严重的疾病。

3 catching   

adj.易传染的，有魅力的，迷人的，接住

参考例句：

• There are those who think eczema is catching.有人就是认为湿疹会传染。
• Enthusiasm is very catching.热情非常富有感染力。

4 survival   

n.留住生命，生存，残存，幸存者

参考例句：

• The doctor told my wife I had a fifty-fifty chance of survival.医生告诉我的妻子，说我活下去的可能性只有50%。
• The old man was a survival of a past age.这位老人是上一代的遗老。

5 investigator   

n.研究者，调查者，审查者

参考例句：

• He was a special investigator for the FBI.他是联邦调查局的特别调查员。
• The investigator was able to deduce the crime and find the criminal.调查者能够推出犯罪过程并锁定罪犯。

6 doctorate   

n.(大学授予的)博士学位

参考例句：

• He hasn't enough credits to get his doctorate.他的学分不够取得博士学位。
• Where did she do her doctorate?她在哪里攻读博士？

7 imperial   

adj.帝王的，至尊的；n.特等品

参考例句：

• They made an objection to the imperial system with resolution.他们坚决反对帝制。
• The Prince Imperial passed away last night.皇太子昨晚去世了。

8 profitable   

adj.有益的，能带来利益的，有利可图的

参考例句：

• That business became profitable last year.那项生意去年变得很赚钱。
• The convention business is very profitable for the hotel industry.承办会议业务能给旅馆业带来很高的利润。

9 spans   

跨度( span的名词复数 )； 持续时间； 一段时间； （五指张开时的）指距

参考例句：

• A steel railway bridge spans the Yalu River. 鸭绿江上有一座钢铁大桥。
• The wire door was a couple of hand-spans from his face. 铁笼门距他的脸只有一两个巴掌远。 来自英汉文学

10 reef   

n.礁，礁石，暗礁

参考例句：

• The ship and its crew were lost on the reef.那条船及船员都触礁遇难了。
• The ship was wrecked on a coral reef.这条船在珊瑚暗礁上撞毁了。

11 helping   

n.食物的一份&adj.帮助人的，辅助的

参考例句：

• The poor children regularly pony up for a second helping of my hamburger. 那些可怜的孩子们总是要求我把我的汉堡包再给他们一份。
• By doing this, they may at times be helping to restore competition. 这样一来, 他在某些时候,有助于竞争的加强。