首页
登录
职称英语
(1)More and more of the world’s supply of seafood is coming from farms.
(1)More and more of the world’s supply of seafood is coming from farms.
游客
2023-10-28
16
管理
问题
(1)More and more of the world’s supply of seafood is coming from farms.
(2)Although 80% of the world’s seafood comes from marine harvests, there is a major shift under way toward aquaculture now.
(3)Nearly 40% of salmon marketed today are raised in captivity, compared with 6% a decade ago. Forty percent of all clams, oysters, and mussels are produced in farm environments, along with 65% of freshwater fish. Between 1990 and 1996, fish-farming production rose from 12.4 million to 23 million tons worldwide, writes Anne Platt McGinn in an article for World Watch magazine.
(4)"The fact that world seafood supplies continue to increase at all is due almost entirely to the phenomenal growth in aquaculture," says McGinn, a research associate at the World Watch Institute. Commercial aquaculture is driven by rising human population at a time when over harvested wild fish stocks are in decline and conventional farm production has leveled off.
(5)Biotechnology is contributing to high-yield aquaculture through transgenics—the transfer of genes from one species to another. Researchers introduce desirable genetic traits into fish, creating hardier stocks. For example, some species of fish have a protein that allows them to live in Arctic waters. By transplanting this "anti-freeze" gene into other species, researchers have created more fish that can survive in extremely cold water, according to Ag-West Biotech, Inc., in Saskatchewan, Canada.
(6)Biotechnologists are attempting to improve a wide range of genetic traits in fish used for aquaculture, developing fish that are larger and faster-growing, more efficient in converting feed into muscle, more tolerant of low oxygen levels in water, and better able to resist disease.
(7)Researchers also are seeking plant-based sources of food as a more efficient alternative to fishmeal. The use of plant protein on fish farms could take some of the pressure off wild fish stocks and address the problem of phosphorous pollution because plants do not contain high phosphorus levels. Wheat, canola, and canola oil are being used as alternative feed for aquaculture, according to Ag-West Biotech, Inc.
(8)While aquaculture produces a reliable source of protein, the industry is rife with environmental problems, asserts McGinn. Perhaps the biggest concern is water pollution: Fish waste and uneaten food accumulates at farm sites and can float directly downstream into water supplies. Farm-related nutrient wastes as well as nitrogen and phosphorus also promote the spread of algal "blooms" that deplete oxygen and kill marine life.
(9)Aquaculture is also an inefficient user of resources, McGinn charges. Fish farms need protein feed, and about 17% of ocean fish, an over harvested wild resource, becomes food for captive-bred fish. "An estimated five kilograms of oceanic fish reduced into fishmeal are required to raise one kilogram of farmed ocean fish or shrimp, representing a large net protein loss," says McGinn.
(10)Fish farming does not have to be an inefficient or polluting industry. McGinn predicts that many consumers will choose sustainably produced fish in the future, just as they prefer dolphin-free tuna today. [br] The author’s attitude towards aquaculture is ______.
选项
A、optimistic
B、negative
C、indifferent
D、uncertain
答案
A
解析
根据末段首句可以推断作者认为水产养殖业在利用率和防污染方面都将有所改善,因此可以看出作者对水产业是乐观的,因此选项A最恰当。
转载请注明原文地址:https://www.tihaiku.com/zcyy/3137415.html
相关试题推荐
[originaltext]W:Hi,didyouhearaboutmyupcomingtriptoNewYork?M:Ithin
[originaltext]M:Oh,IamnotlookingforwardtothisupcomingtriptoEurope.
(1)Moreandmoreoftheworld’ssupplyofseafoodiscomingfromfarms.
PASSAGETWO[br]Whatgoeswithasciencebecomingmoreadvanced?Theagreementa
Thecountrywasonthevergeofbecomingprosperousandsuccessful.Theunderlin
Alongwiththeletterwashispromise______hewouldvisitmethiscomingChris
IwishyoubreakaleginthecomingEnglishspeechcontestTheunderlinedpart
Thetuitionfeesare______tostudentscomingfromlow-incomefamilies.A、approa
Tom’swifewillalwaysstandbyhisside,______whatmay.A、comeB、comingC、came
(1)Easternmedicinesarebecomingmorepopularinthewest,butfewpeoplere
随机试题
[originaltext]W:Withusnow,isMalcolmBricklin,CEOofVisionaryVehicles.M
Itissensibleforhimtoactasifheweremadinthecourt,becauseinthatca
Theclerkofthecompanyenteredthehospital(examine)______.tobeexamined
总资产周转率等于会计期内的销售收入总额除以平均的资产总额,反映了企业的盈利能力
荧光物质被激发后产生的荧光衰减到一定程度所用的时间称为:A.发射光谱 B.激光
站级收费系统是一个小的独立中心,当与上级通信故障或上级计算机出现故障时,应能全部
下列职权中,属于股份有限公司董事会的是()。 ①召集股东会会议 ②决定公
2021年4月,我国本外币贷款余额187.85万亿元,同比增长12%;人民币贷款
人在每一瞬间,将心理活动选择了某些对象而忽略了另一些对象。这一特点指的是注意的(
与磺胺甲噁唑具有协同抑菌和杀菌作用的是()A.甲氧苄啶 B.诺氟沙星 C
最新回复
(
0
)