Hiện trạng nguồn lợi và hoạt động khai thác - Nuôi trồng thủy sản ở đầm phá Tam Giang - Cầu Hai, tỉnh Thừa Thiên Huế

HQI NGH! KHOA HOC TOAN QUOC V £ SINH THAI VA TAI N G U Y £ N SINH VAT U\N THU BA<br /> <br /> <br /> <br /> HIEN TRANG NGUON LOfl VA H O A T DQNG KHAI T H A C - NUOI TRONG<br /> THUY SAN Cf DAM P H A T A M GIANG - CAU HAI, TINH T H I T A THIEN HUE<br /> <br /> -=" LE THI NAM THUAN, NGUVEN-TttI THUY<br /> ' Truang Dgi hpc Khoa hpc, Dgi hpc Hui<br /> <br /> Hf dim phi Tam Giang - Cau Hai, tinh Thira Thien Hue cd ngudn lgi thuy sin phong phii,<br /> thanh phan ngudn gen da dang vdi khoang gan 1000 loii, hifn nay da biet 947 loai. Ci la nhdm<br /> CO thanh phan loai ldn nhat dao ddng tu 171 den 230 loai. Ngudn lgi thuy sin tir dam phi di<br /> cung cip hing ngin tan thuy sin hang nim vi la ngudn thu nhip chinh ciia ngudi din sdng ven<br /> dim phi. Tuy nhien sy khai thic qui miic cic ngudn Igi cd gii tri da va dang Ii nguyen nhin<br /> gay ra nhtrng inh hudng bit Igi nghiem trgng cho da dang sinh hgc cua dim phi. Nhumg inh<br /> hudng ciia cic boat dgng phit trien fren dja bin, cic hinh thii khi hau, thdi tiet nhu mua lut keo<br /> dai va trai miia, bao trii miia, ban khd ndng keo dai... da tic ddng khdng nhd den tdc do suy<br /> giam da dang ngudn lgi sinh vit cua dim phi. T)d ciing la rnuc dich mi cic cac tic gii muon<br /> lam ro va chuyen den ngudi dgc qua bai baonay.<br /> L PHI/ONG PHAP NGHIEN c i r u -<br /> Cac so lifu, thdng fin thu dugc bing cac phuong phip sau:<br /> - Phuang phip dilu tra nghien cim thyc dja: Td chiic dilu tra nghien ciru thyc dja d cac diem<br /> nghien ciiu da xic djnh trong nim 2008 vi nira diu nim 2009.<br /> - Phuang phip hgp nhdm/thio luan nhdm cap cgng dong: Gie cugc thio luan nhdm da td<br /> chiic bao gom cac nhdm ddi tugng tham gia: nhdm nam gidi, nhdm phy ntr, nhdm hat<br /> nhan/nong cot vi nhdm ty quan.<br /> - Thu thap vi phan tich thdng tin thii' cap.<br /> - Tap hgp cic tu lieu lien quan.<br /> « Nghien ciru, sir dung chgn lgc mgt so kit qui nghien ciiu da cd.<br /> - Tu lifu vl boat dgng kinh tl sin xuit thuy sin ciia tinh, huyfn vi cic xa lien quan.<br /> IL KET QUA NGHIEN C t r u<br /> <br /> 1. Thay doi ve thanh phan/so lugng loal<br /> Hifn nay, d hf dim phi da xuat hifn rd sy mat cin ddi giira ngudn lgi cd gia tri vi it gii frj.<br /> Ket qui nghien cihi khio sit tai 4 xa/thj trin vimg dim phi_Phii Vang cho thiy: ca Ong huomg<br /> (Holotes sexlineatus) va Ong biu (Terapon oxyrhynchus) biln mit; ci Ging (Teraponjarbua) it<br /> thay ddi; ci Dia (Siganus guttatus) khdng ed gidng trong ty nhien, chu yeu do nudi. Gidng nudi<br /> phai mua tir Nha Trang, Vinh Hiln. Cira Thuan An khdng cd ci trdi vao nhu tra'rc day do hing<br /> day dit diy frudc cira; ci Chinh (Anguilla) trade diy cd vl nhilu khi lu lut nhu ig hifn nay rit<br /> hilm; ci Doi (Mugil cephalus) giim nhilu, ci gidng cdn khoing 20%); ci Hanh (\canthopagus)<br /> giam rit nhilu din khdng cd, ca giong cdn khoang 25%); ci Diy (Cyprinus cent -alus) giam rit<br /> nhieu so vdi trudc diy, cdn khoing 10-13%); Ghg (Portunuspelagicus, P. tritubei culatus): trade<br /> day rit nhilu hifn nay khdng cd hoic rat it; Cua (Scylla serrata) giam rit nhili, hiu het cd Ii<br /> nhd nudi; Tdm rin (Penaeus semisuleatus) giim khoang 90%) so vdi trade cay; Tdm_nang<br /> (Penaeus japonicus) giim khoang 80%o, nay chi cd d Con Te; Tdm bac (P. mergi ensis) mat hin<br /> (10 nim trade rit nhieu); Tdm 6 rau (Exopalaemon sp.j xuit hifn rit nhilufrrsau lut 1999; Tdm<br /> <br /> <br /> 1103<br />  HOI NGH! KHOA HQC T O A N Q U O C V £ SINH THAI V A TAI N G U Y £ N SINH VAT ikH THU' BA<br /> <br /> <br /> chi (Parapenaeopsis hardwickii) truac day cd nhieu, miy nam tiTidc khdng xuat hifn nhung 2<br /> nim trd lai diy lai cd nhilu; Tdm nuong (P. orientalis) giam nhilu (khoang 90%); Tdm go md<br /> (Alpheidae) giim din hiu nhu khdng xuit hifn. Dgng vat hai manh vd cd nhieu thay doi friy<br /> theo \'ung nude vi phan bo dg man: Tria md Meretrix meretrix trade diy nhieu hifn nay it hoic<br /> khdng cd; Tria giiy (Paphia undulata): 2 nim gin diy cd nhilu, trade day khdng cd; 6e<br /> Cerithidea eingulata tap trang nhilu d viing dim Sam Chuon va Thuy Tii, la thiic an tdt cho cac<br /> loii tdm ei; Rong cau chi ving (Gracilaria sp.) bit diu cd trd lai nhung chii ylu do_nudi frdng;<br /> Rong mim (tio Cladocera) cd nhilu nhit li cic ao nudi cd mdi tradng nude d nhiem nh?, mat<br /> dd phit friln ty If nghjch vdi cd hg; Rong cd hdi (tio Chara): xuit hien nhilu (trade day it) la<br /> loii rong khdng cd lgi cho ci tdm; Rong cd he (Halodule pinifolia) frong d va thuy dao cd<br /> nhung khdng nhieu, trudc diy rit nhieu.<br /> <br /> 2. Mgt so nguyen nhan chinh cua su thay doi<br /> - Cac hoat ddng quy hoach thyc hifn fren viing dam phi dang dan cd tic ddng din hf mdi<br /> tracmg, cic loii thiiy sin fren dam phi.<br /> - Do boat ddng nudi frdng thuy sin (NTTS) bing ao vay ludi phat trien chua kiem soat dugc<br /> tren dam phi.<br /> - Hoat dgng khai thic thuy sin chua cd nhtimg djnh che thyc hifn nghiem khic cy the hoa d<br /> dja phuong. Cac ngu cy khai thic cd tinh huy dift van dang boat dgng. Lir phat trien ngiy cang<br /> nhieu vi khai thic tin dift lam can kift ngudn lgi nhanh chdng hon.<br /> - Khi hiu, thdi tiet cd nhieu bien dgng thay ddi do anh hudng chung cua bien ddi khi hiu<br /> toan. cau vi tic ddng ciia cic boat dgng phat trien d dja phuong.<br /> <br /> 3. Hoat dgng khai thac va nuoi trong thuy san tren dam pha<br /> Hf dam phi Tam Giang - Ciu Hai lien quan din 5 trong tdng sd 9 huyfn, thanh vdi 31 xa,<br /> tdng sd din khoing 300.000 ngudi v i dang trd thinh mgt trong nhtrng vimg kinh tl trgng diem,<br /> phit trien sdi ddng cua tinh Thira Thien - Hul.<br /> 3.1. Khai thac thiiy san tren dam pha<br /> Theo thdng ke cua Sd Ndng nghifp va Phat triln ndng thdn tinh Thira Thien Hul (NN &<br /> PTNT) (2007), qua ba thip nien, sin lugmg khai thic thiiy sin d Tam Giang - Ciu Hai giim gin<br /> mdt nira: Tir 4.500 tan trade nim 1980, nay chi xip xi 2.500 tin. Thdng ke cua Sd va nghien<br /> cim ciia chiing tdi vl boat dgng khai thic thuy sin tren dim pha cd hai nhdm chinh: Nghi khai<br /> thic cd djnh gdm nd, sio (tren 2.000 frg), rd giin (250), chudm (520), day (gin 70). Rieng s6<br /> lugng ving diy cd sai khic vl so lugng thdng ke cdng bo: tren 1.200 vi 1.874. Diy, nd, sao<br /> giing day die, cic phuang tifn khai thic di dgng trin ngap tren dim phi thyc sy frd thanh ndi<br /> biic xiic va ip lyc ldn vdi hf dam phi, giy can trd giao thdng va anh hudng nghiem trgng den<br /> ngudn Igi thiiy sin. Nhdm nghi khai thac di dgng vdi te miy, gia, ludi re 3 Idp cin quet ci con<br /> trong dim. Kit qua dilu fra chi 4 thdn thugc 4/31 xa ven phi (Phii Vang) ma cd din 28.800 tay<br /> ludi; vdi chilu dai lOm/tay, se cd din 288km ludi dai gap 4,2 lin chilu dai dim phi!<br /> Ket qua dilu tra cdn cho tiiiy d thdn Djnh Cu Phu My cd 6 hg xiic dien, viing dim Phii My<br /> CO ngudi ra difn vao ban dem tap hoing tir thing 8 din thing 10 hang nim (sd ngudi nay tir Phii<br /> An, Dap Di, VT Da, Huong Thuy tdi)... Hoic viing ngu tradng Thuan An cd nhilu ngudi khai<br /> thic xung difn vao miia lu lyt. Die bift xa Phii An cd sd hg khai thic bing xung difn d hiu hit<br /> cac thdn: thdn Djnh cu cd 20 hg xiec difn; r i difn cd 1 hg thdn Dinh Cu, 20 hd thdn Thuy Trieu<br /> va 4 hg thdn An Trayin.<br /> <br /> <br /> 1104<br />  HOI NGHI KHOA HQC TOAN QUOC V £ SINH THAI VA TAI NGUY£N SINH VAT Li>N THU BA<br /> <br /> 3.2. Nuoi trong thuy san<br /> Vdi thanh qui quan trgng ciia nghe nudi tdm mang lai tii 1996-1999, difn tich NTTS tiep tuc<br /> phat trien trong 5 nim tiep theo 2000-2005 vdi tdc do ting binh quan dat 16%/nirm Din nam<br /> 2005 difn tich nudi torn toin tinh dat xip xi 4000ha, ting hon 2 lin nim 2000, nang suit bmh<br /> quin nudi tdm dat xip xi 1 tan/ha, gap 2,5 lin so vdi 2000; sin lugng tdm nudi dat tren 3434<br /> tan, ting gip 4 lin so vdi nim 2000. Sau khoing 8 nim phit triln NTTS (1998-2006), difn tich<br /> dim nudi thuy sin da ting khoang 8 lin, tir 579ha (2,33%)) ting len 4287,44ha vi difn tich Iiia<br /> khong thudng xuyen giim tir 3.88Iha (1998) din nay chi cdn 1648,96ha. Thong ke cd khoing<br /> 5740 hg dang boat dgng NTTS quanh dim phi. Nhd dd da gdp phin diy manh chuyen djch co<br /> ciu kinh te ndng thdn viing dam phi theo hudng tich cyc tir khai thic sdng dim vi sin xuit<br /> nong nghifp ning suit thap sang NTTS cd gii trj vi hifu qui cao, gdp phin tao viec lam vi ting<br /> thu nhap cho hom 14000 hd gia dinh vdi 21000 lao ddng. Cic con sd niy chumg td sy gia tang so<br /> hg vi lao ddng khai thic va NTTS hifn nay so vdi giai doan 2004-2005. Giai doan 2006-2008<br /> quy mo nudi NTTS viing dam phi cd mgt sd diem chu y nhu sau (bing 1).<br /> Bdng I<br /> Quy mo nuoi NTTS viing dam pha giai doan 2005 - 2008<br /> Tieu chi Nam 2005 Nam 2006 Nam 2007 Nam 2008<br /> Tong dien tich nuoi lg, bien (ha) 4.012,4 3.881 3.712,1 3.748,6 _<br /> Nuoi chuyen torn su (ha) 1.975,7<br /> 3.444,7 2.815,1<br /> Nuoi torn chan trang (ha) 3.801 116,2<br /> Nuoi xen ghep (ha) 567,7 817 1.525,5<br /> Nuoi long (long) 640 Nhieu Nhieu 746<br /> Tong san lugng nuoi thuy san (tan) 3.967,1 (lg) 4.443 (lg) 4.697,2(lg) 9895,4<br /> Tong san lugng khai thac (tan) 3.720 (Ig)<br /> <br /> Ghi chii: Nguon: Sd NN & PTNT tinh Thira Thien Hul, 2006-2009.<br /> Nhu viy, cd thi thiy difn tich nudi thuy sin nude Ig vi bien theo thdng ke cua Sd NN &<br /> PTNT trong thdi gian tu 2006 - 2008 khdng ting mi cd giim do thyc hifn quy hoach sip xip lai<br /> difn tich nudi thuy sin tren phi cua tinh, trong dd, bao gdm ci vifc trift de thyc hifn khdng<br /> nuoi tom vu 3 trong nim theo chi dao ciia Sd. Vifc thyc hifn quy hoach, giii toi sip xep lai nd<br /> sao d Phu Vang, Quing Diln, Phii Lgc da dem lai mgt so cii thifn vl mdi trucmg: rong ciu phit<br /> trien frd lai viing dim Sam Chudn, Ciu Hai vdi sin lugng thu hoach 595 tan.<br /> Song song vdi md rgng dien tich NTTS, nhieu loai gidng thuy sin da dugc du nhip thuan<br /> duang nhu tdm Rio Metapenaeus, tdm Chin tring (Litopenaeus vannamei), tdm Cing xanh<br /> (Macrobrachium rosenbergii), ci Dia, ci Mii (Epinephelus coioides ) , ck Hong, ngheu Ben tre<br /> (Meretrix lyrata), ck Ddi, ci Kinh, ci Nau (Scatophagus argus), ci Gid (Rachycentron<br /> canadum)... gdp phin timg budc da dang hoi ddi tugng nudi thiiy sin. Ci Niu (Scatophagus<br /> argus) hifn dugc xem la doi tugng nudi cd hifu qui kinh tl cao nhit dugc ngudi din quan tim<br /> phit trien mic dii cdn nhilu khd khin vl nguon gidng, thdi gian nudi keo dii so vdi cic loii ci<br /> die sin khic cua dim phi.<br /> Cic doi tugng nhuyen thi nhu 6c huong (Babylonia areolata), Vgm xanh (Mytilus edulis)<br /> vk Hau (Crassostrea belcheri, C. lungubris), Trai nggc (Pinctata)... dugc dua vao nudi trong<br /> dim Ling Cd vua ting sin lugng va hifu qua kinh tl vira cd tic dyng lam sach mdi tradng.<br /> <br /> <br /> <br /> 1105<br />  HOI NGHI KHOA HQC TOAN Q U O C V £ SINH THAI V A TAI N G U Y £ N SINH VAT L^N THp- BA<br /> <br /> <br /> Nam 2005 vi 2006, da tiiu hoach dugc 210 v i 130 tin gdp phin lam tang s ^ lugng tiiuy sin<br /> nude Ig toin tinh. Nghien ciiu tai cic xa Phu An, Phii My, Phu Xuin va thj frin Thuan An cho<br /> thiy cic dja phuang niy diu cd boat dgng khai thic va NTTS. Thdn Tan Duong (Thuan An) cd<br /> 80%o tdng sd hd nudi vi khai thic, 5% sd hd khai thic tieu nghf. Thdn Thuy Difn (Phu An) cd<br /> 85,3% tdng sd hg nudi vi khai thic, 13,6% hd khai thac tilu nghe. Thdn Djnh Cu (Phu My) cd<br /> 88% tdng sd hd nudi va khai thic; 9,6% hd khai thic tieu nghf. Thdn Thuy Difn (Phii Xuan) cd<br /> 90% tdng sd hd nudi vi khai thic; 5%o hg khai thic tilu nghf. Cic hg nudi d 4 xa/tiij trin nay<br /> diu cho ring nim 2007 va 2008 hg nudi tdm khdng lai ldn nhumg khdng mat fring nhu tmdc<br /> day, lgi nhuin dat dugc khdng qui cao nhung dn djnh hon. Nguyen nhan la do nudi xen ghep<br /> (tdm Sii - ci Dia - ci Mii - ci Kinh -...) khdng nudi don (tdm Sii) nhu trudc day. Do vay, neu<br /> tdm dugc miia thi khdng phii ndi them gi nhung neu mit miia thi van cd ngudn thu tir cac ddi<br /> tugng nudi ghep khdng gay ra hien tugng mat trang vi vd ng nhu 5 nam ve trudc.<br /> 4. Su gia tang cac loai phuong tifn khai thac, danh bat thiiy san<br /> Theo thdng ke cua Sd NN & PTNT vi bio cio ciia Dy an IMOLA (2007) cho thay cd 31 xa,<br /> thj tran (vdi tdng sd 68 thdn/td nghe ci) thudc 5 huyfn thi lien quan den dim phi cd khoang<br /> 3450 hg gia dinh sir dyng xap xi 6000 don vj ngu cu tham gia vio boat ddng khai thic thuy sin.<br /> Hifn cd 19 nghe khai thic dang dugc tien hinh tai dim phi (khdng ke nghe khai thic cd ket hgp difn).<br /> Nghien ciiu tai 4 xa/thj tran ven phi chiing tdi nhan thay cd them mgt loai ngu cy buy dift<br /> dang dugc ngu din sir dung diu tien vdi 30 hg d Phii Vang tir nam 2005 la lir xip. Lit xip cd<br /> ngudn gdc xuit xir tir Trang Quoc. Lir trin ngip fren dim phi dugc ngu dan sir dyng khai thic<br /> tan diet tdm ci... Diu nim 2008 Chi cyc BVNLTS cho bilt cd 2.399 hd vdi hon 133.988 cheo<br /> lir dugc sir dyng khai thac fren hiu het mat nude cua hf dim pha. Qua dilu tra khio sat tii 4<br /> xa/thj fran nim 2009, sd lugng lir khai thic tren vimg nude dim phi cua cic dja phuang niy<br /> tmng binh udc khoing tir 7900 - 12.800 cheo lir (20-25 cheo lir/hg). Neu chi tinh cho tdng so hg<br /> khai tiiic tiiuy sin tren hf dam phi thi cd thi thiy chilu dii ma cic loai lir rii fren dim phi khai<br /> thic tan dift thuy sin hifn nay udc khoing 483km din 776,25km gip 7,103 lin din 11,415 lin<br /> chieu dai cua dim phi! Cheo lir cd thi xip ggn nhg, di chuyin dl ding tren nhilu ngu tradng<br /> nen hifu qui khai thic ciia nghe Iu xep rit cao giy suy giim ngudn lgi thuy sin dim phi la hf<br /> qui tit yeu. Neu tinh diy du ca so ngudi nudi thuy sin (dai nghf) thi con so nay se tang cao ban<br /> nhieu. Dieu niy cho thiy mgt thyc trang la dim phi vi ngudn Igi dim phi dang diing tiirdc mgt<br /> nguy CO mdi do boat ddng khai thic tan dift ngudn lgi thdng qua ngu cy mdi li lir xip. Hifn nay<br /> ngucri din ty sin xuit ra loai ngu cu niy vdi chilu dii, mit ludi dat hifu qui khai thic cao nhit,<br /> dong nghTa vdi vifc la tdm ci... bj khai thac tan dift can kift nhanh nhit!<br /> <br /> Cic phuong tien phuc vy khai thac thuy sin chu ylu la cic loai thuyen cd dgng co vi khdng<br /> cd ddng CO dugc ngudi din ty trang bj. Tdng cgng cd 4097 thuyin dugc sir dyng frong hoat<br /> ddng khai thic, trong dd 1907 thuyin khdng miy, 1732 chiec cd may < 16.5 CV, 458 chile cd<br /> miy > 16.5 CV. Cac con so thong ke niy cd thay ddi theo chilu hudng ting len qua cic nim.<br /> Khio sit d 4 xa/thj frin nam 2008 - 2009 cho thiy hien tai ngudi dan sir dung cic loai thuyin<br /> va ghe udc khoang nhu sau (bang 2).<br /> <br /> Nhu viy, tdng so ghe thuyin cua 4 thdn thugc 4 xa/thj trin nghien cihi tii 1422 - 464 chiec<br /> chiem 34,7% - 35,7% tdng so thuyin toan dim phi so vdi kit qui khao sat ciia Dy an IMOLA<br /> nim 2007 fren 31 tiidn cua tirtii cd boat dgng sin xuit thuy sin tai khu vyc dam phi. Dilu nay<br /> chuiig to day la khu vyc cd sd lugmg thuyin ghe Idn lien quan din sinh ice chu ylu ciia ngudi<br /> dan la sdng dya hoin toin vio nguon lgi thuy sin ciia hf dim pha va la khu vyc thugc 4/5 xa tiij<br /> tran cua tinh cd hoat dgng nudi ao vay phat friln tren dim phi.<br /> <br /> 1106<br />  HOI NGH! KHOA HQC TOAN QUOC V £ SINH THAI VA TAI N G U Y £ N SINH VAT L^N THU BA<br /> <br /> <br /> Bdng 2<br /> Hifn trang sir dyng cac loai thuyen va ghe udc ciia ngudi dan d 4 xa<br /> Tan Duong Djnh Cu Dinh Cu Thuy difn<br /> Loai tliuyen<br /> Thuan An Phii An Phii My Phil XJan<br /> Thuyen may (chiec) 20 20 10(12-15CV) 10<br /> Ghe tre (chiec) 180 590 242-484 280<br /> Ghe nhom (chiec) 20 10 4 10<br /> Ghe nhom co may 6 (5,5-8CV) 20<br /> Tong 220 626 256-298 320<br /> <br /> Ngudn: Kit qua dieu tra nim 2008.<br /> <br /> 5. Hifu qua/san lugng khai thac thuy san<br /> Cac hoat dgng tren d i m phi gdm khai thic va NTTS da gdp phin nudi song tren nira trifu<br /> dan. Phin. ldn sin lugng khai thic ciia 3 nghi re 3 Idp, diy vi nd sao la tdm (chiem 42,11% ±<br /> 2,97% tdng sin lugng khai thic). Cic nghien ciru cho thiy viing dim Sam - Chudn den Thuy Tu<br /> la tmng tam tip trung cao nguon lgi thuy sin cua dim phi nhung tdng trir lugng cao nhat khdng<br /> vugt qui 1408496kg. Ben canh do hifu qui khai thic ngiy cang cd xu hudng syt giam do tic<br /> dong ciia khai thic thilu djnh hudng vi quan Iy thilu chit che. NIU chi tinh rieng vl nudi trdng<br /> thuy sin ning suit nudi tdm suy giim tir 0,977 tin/ha/vy (2005) xuong cd'n 0,776 tin/ha/vu<br /> (2007). Nang suit khai thic tii cac ngu ludi cy cua ngudi din cung cd sy thay ddi theo chieu<br /> hudng ngiy cing khd khin hon thi hifn qua hifu qui kinh te mi hg thu dugc binh quan ngay.<br /> Ket qui khio sit nim 2008-2009 cho thiy: Nghi ludi: 40.000-70.000d/ngay (nim 2004-2005<br /> dat 30.000- 50.000d/ngiy); Lir: cao nhit tir 100.000-150.000d/ngiy, tdi thilu tir 30.000-<br /> 40.000d/ngiy; Nd: 100.000-150.000d/dem (trong d); 20.000d/dem (ngoii d). Trudc day hifu<br /> qua cao ban do cd nhilu tdm ca hon vi khdng cd lir boat dgng khai thic (nim 2004-2005 dat<br /> hifu qua 30.000d/dem d ngoai d). Cin luu y li sd tiln bin thuy sin khai thic thu dugc binh<br /> quan/ngay cd thi cao hom nhumg sin lugng khai thic thi thip hom do trugt gii va khiing hoang<br /> kinh te. .<br /> Mgt loai ci die trung ciia^dim phi li ca Diy (Cyprinus centr.alus) hifn cung bj suy giim sin<br /> lugng nghiem frgng. Nhimg nam 1990 cd sin lugmg khai thic hang nim loii ci Diy dat khoing<br /> 850 din 900 tin nhung hifn nay chi dat 102,8 - 177,3 tin/nim. Sin lugng niy dang ngiy cang<br /> giam do hau qua ciia-boat dgng khai thic cua cic loai lir xip tren dim phi trong thdi gian gin<br /> day.<br /> <br /> 6. Mgt so van de ve djch bfnh tdm trong thdi gian gan day<br /> Nhimg nim gin diy vin de djch bfnh tdm vi tdm chit hing loat vin la vin dl nan giii chua<br /> khic phuc dugc ddi vdi cac ho tdm ven phi Tam Giang - Ciu Hai. Thong ke tir cic bio cio<br /> tong kit ciia Sd NN & PTNT tinh Thira Thien Hul vl vin de niy trong giai doan 2005 - 2009<br /> cho thiy, trong cac nam tii 2005 din 2008 diu cd djch tdm bfnh xay ra, trong dd djch bfnh xiy<br /> rafrendifn rgng nhat la nam 2007 vi thip nhit la nim 2008.<br /> Mgt thyc trang luu y li bfnh tdm thudng xiy ra vio thdi diem thing 3 din thing 6 - la thdi<br /> gian nhift dg tang thit thucmg kem theo mua ddng vi mua axit, dg man ting cao vi xam nhip<br /> <br /> <br /> 1107<br />  HOI NGHI KHOA HOC T O A N Q U O C V £ SINH THAI V A TAI N G U Y £ N SINH VAT UkN THCT BA<br /> <br /> <br /> sau vao dim phi keo theo thay ddi dg pH gay anh hudng khdng tdt din co chl dilu hoa tiiim<br /> thiu ciia co thi tdm ci. Nguyen nhan giy bfnh tdm cdn lien quan din nhtrng thay ddi bit<br /> thudng cua khi hau thdi tilt, vifc quan ly ao nudi, quan ly chit lugng gidng... Thdi gian nay torn<br /> nudi vy chinh sip thu hoach vi vy phy cung bj anh hudng gay that thu cho ngudi nudi va ngudn<br /> luc kinh tl xa hdi dia phuong.<br /> <br /> Di$n t'ch (ha) D Tdng dl$n<br /> 5000<br /> tich t6m nu6i<br /> D Di$n tich t6n-<br /> nu6l b| b$nh<br /> <br /> <br /> <br /> <br /> 2005 2006 2007 2008<br /> Thib'i gian (nSm)<br /> <br /> <br /> <br /> <br /> Hinh I: Bieu do so sanh difn tich tdm nuoi bj bfnh va tong difn tfch torn nuoi<br /> tren toan tinh Thira Thien Hue giai doan 2005 - 2008<br /> <br /> HI. KET LUAN VA DE NGHJ<br /> 1. Dudi inh hudng ciia cic boat dgng khai thic vi NTTS cua con ngudi cimg vdi dan so<br /> ting, nhtrng bien ddi khic nghift cua khi hau thdi tiet va thien tai, hang chyc loai thuy sin da<br /> bien mit hoic s'uy giim; so lugng loii xuat hien mdi va phyc hoi khdng dang^kl lam diy nhanh<br /> tdc dg can kift ngudn Igi thuy sin v i da dang sinh hgc viing dam phi.<br /> 2. Ngu cy khai thac buy diet gdm xifc difn, ra dien va die biet la lir dang la nhirng nguyen<br /> nhin trade mit vi liu dai gay suy giam nghiem trgng ngudn lgi thuy san ciia dam pha. Hifu qua<br /> khai thic thuy sin, nang suit nudi tdm hang nim giam Ii nhirng van de phai chii trgng giii<br /> quyet trong chien luge phat trien ben viing kinh te thuy san vdi bao vf mdi trudng vi da dang<br /> sinh hgc tren hf dam pha va dai ven biln tinh Thira Thien Hue.<br /> 3. Djch bfnh tdm fren dam phi ven bien Thira Thien Hul vin diln ra lien tuc tir nam 2005<br /> den 2008, la hau qui ciia nhieu nguyen nhan trong dd cd biln ddi kW hau, thdi tilt, nhtimg yeu<br /> kem ve quin Iy siic khoe vat nudi, quin ly phdng chong djch...<br /> 4. Kiem nghifm them tren cac viing nudi, gia tang tin suit liy miu va phan tich chit lugng<br /> nude trong nudi trdng thuy sin de cd danh gia dn djnh v i diy dii hon. Tim hilu, dinh gia sy anh<br /> hudng cua biln doi khi hau, khung hoang kinh tl, cic cdng trinh thuy lgi fren cic he thong song<br /> den ddng chiy, mdi tradng sinh thai va da dang sinh hgc he dim pha, din sinh kl cua cgng<br /> ddng ngu dan ven phi.<br /> <br /> TAI LIfU THAM KHAO<br /> 1. Chi cyc Bao vf Nguon Igi Thuy san Thira Thien Hue, 2007: Bio cio Tdng kit Khio<br /> sat/Kiem ke ho^t dgng khai thic va nudi thuy sin (cd sy hd trg cua GIS) d hf dim phi<br /> Tam Giang - Ciu Hai, tinh Thira Thien Hul. Dy an IMOLA.<br /> 2. Nguyen Thj Kim Lan, Bui Lai, 2007: Tap chi Thuy san, 7: 27-30.<br /> <br /> <br /> 1108<br />  HOI NGH! KHOA HQC TOAN QUOC V £ SINH THAI VA TAI NGUY£N SINH VAT L^.N THLf BA<br /> <br /> 3. Nguyen Hirii Quyet, 2007: Tap chi Khoa hgc Dai hgc Hue, 37: 119-124.<br /> 4. Pham Thj Hong Nga, 2008: Tap chi Ndng nghifp vi Phit frien ndng thdn, 6/2008. Ha<br /> Ngi.<br /> 5. Sd Nong nghifp va Phat trien nong thon Thira Thien Hue: Bio cio ket quf NTTS vi<br /> phuang hudng, nhifm vy kl hoach cic nim 2005 & 2006, 2006 & 2007, 2007 & 2008,<br /> 2008 & 2009.<br /> 6. Le Thj Nam Thuan, 2007: Tap chi Thuy sin, 7: 23-26.<br /> 7. Do Cdng Thung, 2006: Tai nguyen va mdi tradng dim phi Tam Giang - Cau Hai, tinh<br /> Thira Thien Hue. Dy an IMOLA, Hul.<br /> <br /> STATUS OF AQUATIC RESOURCES, EXPLOITATION, AND AQUACULTURE<br /> ACTIVITIES IN TAM GIANG - CAU HAI LAGOON<br /> THUA THIEN HUE PROVINCE V<br /> ._ . LE THI NAM THUAN, NGUYEN THI THUY<br /> <br /> SUMMARY<br /> <br /> This paper discusses the status of changes ui aquatic resources in Tam Giang - Cau Hai<br /> lagoon, Thua Thien Hue province. Tens of fish, shrimp and seagrass species in tiie lagoon<br /> having decreased and escaped, •whereas the human population living-in the surroundings of the<br /> lagoon continue to increase. The pressure of exploitation and aquaculmre still have not stopped<br /> the decreasing trend and the management is not effective. The issues of environment, weather,<br /> and climate change have to be taken more seriously. _ .<br /> <br /> <br /> <br /> <br /> 1109<br />