Bạn đang xem bản rút gọn của tài liệu. Xem và tải ngay bản đầy đủ của tài liệu tại đây (122.53 KB, 2 trang )
commercialfishintheworldatorbeyondthe
levelatwhichtheycansustainthemselves.
Inadditiontodangerouslydepletingits
targetfishpopulations,modernfishingcauses
collateraldamagetootherspecies,the
“bycatch”ofundiscriminatingnetsandlines
thatissimplydiscarded,anditcandamage
ocean-bottomhabitats.Fishingisalsoan
unpredictable,dangerousjob,subjecttothe
uncertaintiesofweatherandthehazardsof
workingatseawithheavyequipment.Tothis
highlyproblematicsystemofproduction,
thereisanincreasinglyimportantalternative:
aquaculture,orfishfarming,whichinmany
partsoftheworldgoesbackthousandsof
years.TodayintheUnitedStates,allofthe
rainbowtroutandnearlyallofthecatfishsold
arefarmedonlandinvariouskindsofponds
andtanks.Norwaypioneeredtheocean
farmingofAtlanticsalmoninlargeoffshore
pensinthe1960s;andtodaymorethanathird
ofthesalmoneatenintheworldisfarmedin
EuropeandNorthandSouthAmerica.Abouta
thirdoftheworldwarm-watershrimpharvest
iscultured,mainlyinAsia.Inall,about70
speciesarenowfarmedworldwide.
AdvantagesandDrawbacksofAquaculture
Thereareseveraldistinctadvantagesto