首页
登录
职称英语
(l)More and more of the world’s supply of seafood is coming from farms.
(l)More and more of the world’s supply of seafood is coming from farms.
游客
2023-10-30
34
管理
问题
(l)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] All the following statements are the reasons why commercial aquaculture is pushed forward EXCEPT _____.
选项
A、the human population is increasing fast
B、the wild fish stocks are decreasing due to over fishing
C、the cost of developing aquaculture is comparatively low
D、there is no improvement in conventional farm production
答案
C
解析
细节题。第4段末句提到了三个刺激水产养殖业快速发展的原因,只有C项不是原因之一。注意题干中的EXCEPT。
转载请注明原文地址:https://tihaiku.com/zcyy/3144354.html
相关试题推荐
(1)Onenightwhilstonpatrol,Inoticedastrangeflickeringlightcomingf
(1)Onenightwhilstonpatrol,Inoticedastrangeflickeringlightcomingf
(l)Moreandmoreoftheworld’ssupplyofseafoodiscomingfromfarms.
(l)Moreandmoreoftheworld’ssupplyofseafoodiscomingfromfarms.
(l)Easternmedicinesarebecomingmorepopularinthewest,butfewpeopler
PASSAGETWO[br]Whatgoeswithasciencebecomingmoreadvanced?Theagreementa
[originaltext]W:Hi,LondonPremierTours.HowcanIhelp?M:Hi,[6]I’mcoming
[originaltext]W:Hi,LondonPremierTours.HowcanIhelp?M:Hi,[6]I’mcoming
[originaltext]W:Hi.Thanksforcomingtotheinterviewtoday.It’snicetomee
[originaltext]W:Hi.Thanksforcomingtotheinterviewtoday.It’snicetomee
随机试题
Whereisthewomangoingtogoonholidaythisyear?[br][originaltext]M:Are
InmyearlychildhoodIreceivednoformalreligiouseducation.Idid,ofcou
冰点降低为-0.52℃的溶液()A.等渗溶液 B.等张溶液 C.低渗溶液
患者女,24岁,新婚,突发左侧腰痛1周,寒战、高热1天,查体:体温39.2℃,血
建设工程项目实施过程中发生的下列情形,不能申请行政复议的是()。A、甲施工企业参
A.早发性胎心减速 B.晚期减速 C.变异减速 D.NST有反应 E.N
皮肤∶器官∶调节体温A.税票∶凭证∶分配收入 B.酒店∶场所∶接待宾客 C.
获致身份指的是一个人经历某种公开的、具有竞争性的活动或因具备某种特殊的本领而获得
女,35岁。拔除下颌智齿后5天,出现持续性疼痛。如拔牙窝内有腐败坏死物,有臭味,
一个厌恶风险的投资者应选择()的债券基金。A.久期较短 B.久期较长 C.利
最新回复
(
0
)