KHOA HOC C d N G N G H l
THAIXIH P H A I X I L O A I CA GIOIXIG V A T l l V H HllXIH K H A I T H A C C A GIOIXIG T R O I V A O D A M P H A TAIVI GIAIXIG -
C A U H A i Q U A CLTA BIEIXI THLIAIXI AIXI - PHLI VAIXIG - T H I J A THIEIXI - H U E
Trin Tiu Thu Suong^ Vd Diic Nghla^
T6MTAT
NghiSn ciiu nay duoc tiiirc hi$n tir thang 1 nam 2013 ddn thang 12 nam 2013 thong qua viec khao sat 107 ho thu6c thi trfc Thuin An va xa Phii Thuan co lam nghd khai thkc ca gidng troi vio cua bidn Thu^n An. Kdt qua khao sat cho thay, ngudi dan thu vdt ck gidng chu yeu b ^ g 4 hinh thiic, do la: nghd day, nghd nd sao, ngbe lir va nghd rd gian, trong d6 sd hp lam nghe day chiem ty le cao nhit, tuy nhign ca thu dupc tir nghd day c6 chit lupng kem, siic khoe ydu n^n ty 16 chet rit cao trong qua trinh uong nuoi. Da xac dinh duoc 26 loai ca gidng d d4m pha CO nguon gdc ttr bidn troi vao, trong d6 c6 8 loai ca gidng co gia tri kinh td dang dupc nudi phd bien d vimg Thuan An va Phu Thu^n la ca dia {Siganus guttatus), ca dia vang (Siganus canalicuhtus), ck mU {Epinephelus coioides), ck nkn {Scatophagus argus), ca hdng {Lutjanus spp.), ca hanh {Spams latu^ vk ck ddi muc Mugil cephalus vi ci ddi la Mugdkelearti. Sd lupng ca troi vko nhidu nhat la ca dia ving (ca kinh hay ca rd) khoang 25.000.000 con, ca dia 540.000 con, ca mu 140.000 con, ca hanb, ca hong 30.000 con va cd nau 20.000 con. Mua vu xudt hien ca gidng troi vao cua bidn d cac loii khac nhau keo dii tir thang 3 ddn ttiAng 11 am lich; d nhimg thang trong nam vin khai thac duoc ca gidng co kich thudc ldn hon, 2-5 cm, do ca troi vio va sdng trong dam pha mpt thdi gian.
Tu khda: Ca gidng, cm bidn Thu$n An, mda vu, nghi khai diic, sd luong, thinh phin loii.
1. BAT VAN H i
Hfi dim pha Tam Giang-Ciu Hai bao gdm 3 phan: Phi Tam Giang (52 km^. Dim Sam va dam Thuy Tti (60 km^, Dam Cau Hai (104 km^. Vung dit ngap nudc dim phi Tam Giang-Cau Hai cd tdng di§n tich 248,7 km^, chiem khoang mgt niia tong dien tich dim pha ven bd Vifit Nam (480,5 km^. Day duoc danh gia la hfi dam pha ldn nhat Ddng Nam A.
Ciia Thuan An (trudc day ggi la cua Eo hay cua Ndn) la mdt trong hai cua bidn cua hd dim pha Tam Giang - Clu Hai, li noi tiidng pha Tam Giang vdi Bidn Dfing. Hang nam, noi day nhan lupng con gifi'ng tir bidn trdi vao vdi sd lupng ldn, thanh phin loai da iang, phong phii, cung cap ngudn gidng ding kd cho ludi trdng thuy sin cua cac vimg ven phi d TTiira rhifin - Hud. Vi vay ngudn ci bidn gidng dupc vdt tii
^ nhifin dang giu mdt vi tri quan trgng trong vific :ung cap con gidng phuc vu trong nudi trdng thuy san.
Thira Thifin - Hud la mdt tinh cd tiem nang phat rien ve khai thac cung nhu nudi trdng thiiy san, rong khi dd, ngudn ca gidng man lp ddn nay hiu ihu cho sinh san nhan tao chua thanh cdng, ngudi ludi su dung con gidng tu nhifin la chii yeu.
Mat khac, trong nhirng nam gan day, nghd nudi tdm d nhting viing ven dam pha tinh Thira Thien - Hud dang ddi mat vdi thach thiic to ldn dd la su d nhidm mdi tnrdng vung nudi din ddn dich bdnh. Vi vay ngudi nufii chuydn sang hinh thiic nudi kdt hpp cac loai ca kinh te tir ngudn gidng tu nhifin sin cd d dim phi, day li mdt trong nhirng giai phip nhlm ban chd dich bfinh ddng thdi sii dung hifiu qua ngudn lpi ca gidng ty nhifin d trong dim pha.
Nghien ciiu nay dupc thyc hifin nham xac dinh thanh phan cac bai ca gidng trdi tii bidn vao dam pha tai cua bien Thuan An, xac dinh mua vu xuit hien ca gidng, cac loai ngu cu str dung khai thic va sd lugng ca gidng danh bit hang nam lam ca sd cho vific khai thac nguon ca gidng tu nhien cd hifiu qua, cung cap con gidng cho vific nudi cac ddi tupng nay.
Z. VAT UEU VA PHUONG PHAP NGHIBU CUU
2.1. vat l i ^ nghifin ciiu
Cac loai ca gidng trfii tir bidn vao dam phi Tam Giang - Ciu Hai qua cua bien Thuan An - huyfin Phii Vang - Tmh Thiia Thifin - Hud.
2.2. Phuong phip nghifin cihi
TTiu thap sd hfiu thii cip thdng qua cac tai Ueu nghifin ciiu da dupc cdng bd, sd heu thdng ke cua cac ban, nginh trong tinh.
Khoa Thuy san, Tnrdng Dai hoc Nong Lam Hue
ilONG NGHIEP VA PHAT TRIEN NONG THON - KY 2 - THANG 12/2014
109
Thu thap sd Hfiu sa cap thfing qua vific thu mau ca gidng, didu tra cac hfi khai thac ca gidng d thi tran Thuan An va Phii Thuan. Su dung phuang phap phdng vin true tidp cac hg dan khai tiiac ca gidng de thu thap thfing tin sa cap. Ngi dung phdng vln dua tren phieu didu tra da dupc lap sSn ket hgp vdi nhung h-ao ddi md. Tidn hanh didu tra khio sit 107 hd thudc 2 xa Phli Thuan va thi trio Thuan An cd hoat ddng khai thac ca gidng d cua bidn Thuan An, trong do cd 55 hp iam nghe day, 22 hd lam nghe nd sao, 14 hd lim nghe rd gian va 16 hd lim nghd lir kdt hpp vdi cac nghd khac.
Nghifin ciiu thanh phan loii ca gidng bang phuang phap thu miu, xir ly mlu va phan loai. Khi cd ca gidng trdi vao dam phi, tien hinh thu miu ciing
ttiu phai nguyen ven, khdng triy xudc, sau dd ngSm h-ong dung dich fomol 496 va tien hanh phan loai M\
vdi miu thu cd Mch thirdc nhd (<1 cm) xic dinh thanh phin loai bang kmh nghiem cua ngudi dan dja phuong; ddi vdi miu ca cd kich thudc ldn hon (2^
cm) hdn hanh phan loai c i dya vao cac chi tifiu # hinh thai. Cac tii lieu de phan loai: Vuong Di Khang (1958), Mai Dinh Yen va cdng sy (1992), Nguyh Van Hao (2001), hfi thdng phan loai c i cua Fish Base (2010). Tfin cac loai ca dupc chinh, sua theo FAO (1999) va sip xep cac bac phan loai theo Linberg G, U.viRass(1971).
3. KET QUA NGHDI CUU VA THAO LUAN
3.1. Thinh phin loii c i gidng trfii vio dim pH qua cua bidn Tliu$n An
vdi ngu dan lam nghd thu ca gidng d d i m pha. Mlu
Bang 1. Hianh phan loii c i gidng vao dim phi a cua biln Thuan An STT
I fl)
1 (2) 2 (3) 3 4 5 (4) 6 (5) 7 8 9 10 (6) 11 12 (7) 13 14 (8) 15 (9) 16 17 (10)
BAC PHAN LOAI Tfin Viet Nam
BO CAVUOC Ho ca chem Ci chem Ho ca chim mit to Ca chun mat to Ho ca cang Ca cang mdm nhon c a ong cang Ca cang dan Ho ca due bidn c a due bidn Ho c i hdng C i hdng anh C i hdng cham den c a hdng tron c a hdng do Hg ca trap c a trap vay vang
catrap
Hg ca dia c a dia cdng c a dia vang Ho ca nau Canau Ho ca mdm Ca mdm gai dai Ca mdm gai ngan Ho ca liet
Tfin Idioa hoc PERCIFORMES Centropomidae
Lates calcarifer (^hch, 1790) Monodactyhdae
Monodactylus argenteus (Linnaeus, 1758) Teraponidae
Rhynchopelates oxyrhynches Crerminck & Schlegel, 1846) Teraponjarbua (Forsskal, 1775)
Terapon therap (Cuvier et Valenciennes, 1829) Sillagirudae
Sillago sihama (Forsskal, 1775) Lutianidae
Lut/anusjohnii (^loch, 1792) lethrinus lenti'an (Lacepede, 1804) Lutjanus valgiensis (Quoy & Gahnard, 1824) Uitianus erythropterus (Bloch, 1790) Sparidae
Acanthopagrus latus (Houttuyn, 1782) Spams latus (Houttuyn, 1782) Siganidae
Siganus guttatiis (Bloch, 1787) Siganus canaUculatus (Park, 1797) Scatophagidae
Scatophagus argus (Linnaeus, 1766) Gprridap
Gerrestilamentosus ^uvier et Valenciennes,1829) Genres lucidus (Cuvier, 1830)
Leiognathidae
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1
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no NONG NGHIEP VA PHAT TRIEN NONG THON - KY 2 - THANG 12/201*
KHOA HOC CONG NGHE
18 (U) 19 (12) 20 (13)
21 (14)
22
n
(15) 23 24
in
(16)25 IV (17) 26
Cahfitldn H o c a d u c a dil xanh Ho ca mu Ca mii cham nau Hp ca khe c a chi vang Ho ca son c a son vachen BOCADOI Ho ca ddi Ca ddi muc
ca ddi la
BOCAMULAN Hp ca chai Cachai BOCANHEO Ho ca lie Ca uc gai memLeiognathus equulus (Forsskal, 1775) Sciaenidae
Nibeacoibor i^amWton, 1822) Serramdae
Epinephelus coioides Carangidae
Selaroides leptolepis (Cuvier, 1833) Ambassidae
Ambassis racAeffi?'(Richardson,1846) MUGHJFORMES
Mugilidae
Mugil cephalus (^cYiaxAson, 1846) MugHkelaartii {Gunner, 1861) SCORPAENIFORMES Platycephalidae
Platycephalus indicus (Lmnaeus, 1758) SILURIFORMES
Ariidae
Arius malacanthus (Smith, 1945) Trong thdi gian nghien ciiu tir thang 1/2013 ddn
tiiang 12/2013, da xac dinh 26 b a i ca kich cd ca gidng thuOc 17 hp va 4 bfi troi vao dim phi qua cua bidn Thiuan An. Trong dd bd c i vupc (Perciformes) cd sd lupng loai cao nhit gdm 14 hp (chiem 82,4%) va 22 loai (chiem 84,6%); bfi c i ddi cd 1 ho (5,9%) va 2 loai (chidm 7,7%); bp c i mu lan va bg ca nheo cd 1 ho (chiem 5,9%) v i 1 loai (chidm 3,8%).
Trong 26 loai ca gidng a bang 1, cd mdt sd loai 3a va dang dupc nudi phd bien d vung dim phi do :hung cd gii tri dinh dudng cao, nhu ciu tifiu thu Idn, l i ddi tupng dfi nudi vi vay mang lai gia tri kinh :e cao cho ngirdi nudi. Bfin canh dd, hang nam den nua vu xuat hifin cac ddi tupng nay tir bien trdi vio lim phi vdi sd luong rat ldn dupc ngirdi dan thu vdt am ngudn giong cung cap cho nudi trdng thiiy san, rong dd ca dia cdng Siganus guttatiis, ca dia ving [ci kinh) S. canaUculatus, c i niu Scatophagus argus;
'A ddi cd 2 loai l i c i ddi la Mugil keleartiva ca ddi nuc Mugil cephalus, c i mu Epinephelus coioides, ca rap Spams latus, ca hdng Uitjanus spp. (bang 2).
Mdt dac diem khac bifit giua cua bidn Thuan An -a cua bidn Tu Hidn la d cira bien Thuan An khdng :uat hien c i vlu {Caranxignobilis), ca vSu chi di vio Iam p h i qua cua bien Tu Hidn vi vay nd dupc ngudi Ian d cac vung nhu Ldc Binh va Vinh Hidn thu gom igudn gidng, phuc vu cho vific cung cap ngudn ca
gidng dd uang nufii ddi tupng nay d Ldc Binh, Vinh Hien, Vinh Giang.
Bang 2. MOt sd loii c i cd g i i tri kinh ^ dugc nudi phd bidn d Tiiuan An
STT 1 2 3 4 5 6 7 8
Ten Viet Nam Cadia
Ca kinh (ci dia ving) Cinau
C i ddi l i Ca ddi muc
camii
Catrip C i hdngTen khoa hoc Siganus guttatus Siganus canaUculatus Scatophagus argus Mugilkelearti Mugil cephalus Epinephelus coioides Spams latus Lutjanus spp.
3.2. Tinh hinh khai thic ca gidng b cua bidn Thuan An
3.2.1. Die diem cua cic hd din khai thac ci gidng
Khai thac thuy sin la mdt trong nhiing nghd truydn thdng da cd tu lau ddi cua cic ngu dan ven dim phi. Hoat dfing nay da gdp phan rat ldn vio sy phat tridn ndn kmh td dia phuong, tao cdng an viec iam, tang thu nhap cho ngirdi dan d khu vyc nay.
Kdt qui dieu tra cho thay cac hd dan khai thac ca gidng d dia bin nghifin ciiu hlu het cd cupc sdng khd khan, miic thu nhap thap va khdng on dinh, con cai ddng. Mat khac, trinh dp cua cic hd dan lam nghd khai thac d day chu yeu hoc het tieu hpc (chiem 44%), phd thfing co sd (46%) va sd ngudi cd trinh dp trung hoc phd thdng trd len thip chiem 10%.
JONG NGHIEP VA PHAT TRIEN NONG THON - KY 2 - THANG 12/2014 111
Hinh 1. Trinh do ngu dan tham gia khai fliic
&£lysan
Ben canh dd, kinh nghifim khai thac thuy san, dac bifit khai tiiic ca gidng ciia c i c hd dan d day r l t cao. Hiu het day l i nghd "cha truydn con ndi", ndn hp cd rat nhidu kinh nghiem. Hp nam r i t rd thdi gian cua timg loii ca gidng ngoii bidn trdi vio dam pha, mua vu sinh sin, miia c i di cu, dinh c i tiieo timg con nudc,...de tidn hanh tiiu vdt ca gidng phuc vu cho nudi trdng thuy sin. Qua didu tra nhan thiy ring cd 40,19% sd hd khai thac cd tham nien trong nghd kha lau 10-20 nam v i 59,81% sd hd cd kinh nghiem khai thic trfin 20 nam.
3.2.2. Cic nghi khai tiiic ci gidng
Khi tham gia vio boat dfing khai thic c i gidng, ngudi dan d thi trin Thuin An va xa Phii Thuan su dung cac phuong tien chii ydu nhu: day, nd sao, rd gian, lii, trong dd nghd day su dung nhieu nhit vdi ty le 51%, rd giin 13%, nd sio 21%, lir chiem 15%.
Bang 3. Ty 1^ % c i c phuang ti^n Sli dirng khai t h i c c i gidng
STT 1 2 3 4
Nffh^ khai thac Ngh6 day Ngh^ n6 sao Nghi ro Ngh« lie
T y l 6 h 6 s u d u n g ( % ) 51 21 13 15 Nghe diy khai thic theo nguyen tac lpc nudc bit ca. c a hi liia vao ludi dudi t i c dung cua dong chay va bi giu lai d dut ludi (Le Van Mien, 2006). O vimg cua bien Thuan An, ngudi din chu ydu su dung nghd diy dd khai ihac c i gidng chiem 51%, mdi hg cd it nhit 1 mieng dly, trung binh cd 3 4 mieng, cd hd cd 8-10 midng diy.
Tidp den la nghe nd sao chidm 21%. Theo Lfi Van Mifin va ddng tic gia (2005), dim p h i Tam Giang- Cau Hai cd clu tao diy nong nfin r i t phii hpp vdi
nghd nd sio. Cdn c i c nghd cau, rd gian, ty lfi su dung dd khai tiiac ca gidng t h i p hon do sd lugng ca khaj |
t h i c i t [ Ket qua didu tra ciing cho thay, ngudi dSn lin
nghd khai thac khdng i thuc dupc tac hai cua vi6c sfi dung cic ngu cu cd mit ludi q u i nhd se anh huol^
den vific p h i hiiy mdi tnrdng va ngudn lpi ca ty nhien. Vi vay mac du da dupc tuyfin truydn, tham ^•
c i c khda tap huln vd vific su dung cac loai ngu cu tiiich hpp trong khai t h i c ca nhim bao ve mof trudng, nhung hp vin sii dung cac ngu cu cd mat lii6i q u i nhd so vdi quy dinh de thu dupc c i bat kd IW-, hay bd. Hg khdng hd nghi rang vdi sd c i be niy sau mdt thdi gian ngan se cho ra mdt sd lirpng ca rltl6n cd gia tii kinh te. Kich thudc mat ludi khai thdc ciia cic ngu cu dupc thd hifin dbang 4.
Bing 4. Kich cd m i t ludi cua c i c ngu cy sii d^iig khai tfaicci gidng
STT
1 2 3 4
Nghi khai thac N g h i day Nghi no sao Nghe ro gian N g h i lir
Kich Cff m i t luoi khai thdc
2a (mm) 5-8 5 « 6-10
5-8
Kich CO mat 1 luoi cho phe^
2a (mm)* I 18 H 18 -«
18 ' 18 «
*Ngu6m Td tiinli sd 02/TTr-SNN-TS, nM 12/01/2011 - Sd Ndng nghiep va Phat tiien ndng tiidn Thua Ihien -Hud.
Ket qua khao sat a bang 4 cho thiy, hau het (*
ngu cu sii dtmg khai thac diu cd kich cof mat luoi khai thac nho hon nhiiu so v6i kich ca mdt luoi cho phep. Doi Vffi n g h i ddy, theo khao sdt nam 2003 sfl khau ddy t r t a toan dam phd Tam Giang- Cau Hai li 982 voi mat luoi diit day 2a=2-5 mm, trong do 50 dil CO 2a=2 mm va 932 ddy co 2a-5 mm (Le Van Mi&i nl cdng str, 2005). Cho d i n nay kich cO mfe luoi 2a-M mm da duoc cai thi^n so voi trudc nhung vdn cdD nho hon nhiiu so v6i quy dinh. Chinh vi vay, su dung n g h i ddy khai thdc se thu duoc cd giong co chS lirong kim, sire khoe yeu, tap trung nhiiu o dut diy n6n d i chit. Theo tinh toan ciia Le Vdn Miin vd c^ng su (2005) thi san luong khai thdc cd tu nhiSn cui n g h i day U-6n phd Tam Giang-Cdu Hai dat 513 tan/ndm, chiim hon V* tong san luong khai thdc tr|!i todn dam pha trong nhiing nam gan ddy (khoing 2.000 t&/nam). T6m cd bi chet d cdc dijt ddy c6 mi ludi Off nhd a2 cao hon 26,814n so vdi cdc day c6 mS' luoi cO a5. Hdng nam cd hon nira ty du t h i thdy san bi chit bdi nghe day.
112
NONG NGHIEP VA PHAT TRIEN N 6 N G THON - KY 2 - THANG 12/2014
KHOA HOC CONG NGHE
Tuong ty, nghd nd sao la nghd phd bidn d dam )ha Tam Giang-Cau Hai, nd sao dupc giang hang
;hang chit trfin dim phi, khdng cd quy hoach lam :an trd giao thdng cQng nhu han chd dudng di :huydn ciia ca. Khoing each dat cac trd sao: hang :ach hang cd noi chi cd 5-10 m, trp each trd 4-5 m,
;anh sao ti-ii dai 300-500 m, cd trd dai ddn 1,5 km. O Jay su dung hiu hdt la sao mimg bang vat lifiu 3olye1ylen, kich tiiudc mat ludi rlt nho 2a=5-8 mm.
rheo Nguyfin Himg, (2004) khau dd mat ludi ciia nd jio li 5 mm ndn bat dupc nhung loii ca rat nhd.
Nghd rd gian su: dung mat ludi cd kich thudc ldn ion so vdi cac nghd khic 2a=6-10 mm. Theo nghifin :iiu cua Trung tam Gidng thuy san tinh Thua Thifin - Hud (2007 ) vific vdt ci con trdi hi ngoai bidn vao tin ighd rd cd hifiu qua cao nhit khdng chi vd sd lugng :a con dinh bat dupc trung bmh trfin ngu cu, ma
;hit lupng ca con danh bat dupc ciing tdt hon nghd id vi nghe diy. Tuy nhifin hifin nay sd lupng ca con ianh bat dugc bang nghd rd giin it han rat nhidu so /di cac nghd khic, nfin it dupc ngudi dan su dung.
3.2.3. Mua vu vi sd luong ca gidng khai thic
Bing 5. Mtia vu vi sd lupng khai thic mOt sd loii ci
gidng cd gii tr; kinh td b vting ctia bidn Thuln An (Phu Thu^ vi Thuan An)
STT1 2 3 4 5 6 7
Loaicd Cddia Cd kinh (cd dia vdng)
Cdndu Cdddi Cdmii Cdhdng Cd trdp (cd hanh)
Miia vu khai thdc chinh T5-T6,T10 (am lich) T3-T4 (dm lich) TlO-Tll (am lich)
T3-T4 (am lich) T7-T8,T11 (dm lich) T7-T9 (am lich)
T6-T9 (dm lich)
Sd lirong (con) 540.000 25.000.000
20.000
140.000 30.000 30000
Mua vu khai tiiac cac loai ci gidng b dam phi ifin ra quanh nam. Tuy nhien ngudi dan chi quan hn den mua vy khai thac ca bOt trdi ttr dim phi vio ua ciia bien Thuan An vdi sd lupng ldn cua nhung lii ca cd gia tri kmh td hien nay (bang 5). Mua vu hinh khai thac ci gidng keo dai tir thang 3 ddn ling 11 am lich hing nam. TTidi diem khai thac
gidng chinh la khi ca con tir bien trdi vao qua cira Thuan An vi Tu Hien vdi sd lupng ldn. Khi dd cac hd dan lam nghd day, nghd rd gian va nghd nd se tidn hanh khai thac gidng va bin lai con gidng cho nhiing ngudi uang nudi trong vung.
Kdt qui dieu tra b bang 5 cho thay, mua vu chinh khai thic ci bdt tii bien trdi vao dim pha a mfii loai khic nhau. Khi ca hot trdi vio kich co ca <1 cm, ngudi dan khai thac ca bang nghd diy, nghd rd giin va nghe nd sao li chu yeu vdi sd lugng ldn tu vai ngan den vai van con. Ngoai ra, ck hot vao phi, nhd ngudn thiic an trong dim phi ddi dao, chiing sinh trudng rat nhanh. Cac thdi didm khac trong nam, cd thd khai thac dupc ca con, ca trudng thanh trong phi (Phan vifin Hii duong hpc Hii Phdng, 2001).
Ca dia. nam 2013, ca dia gidng di vao dam pha d
ciia bidn Thu^n An vao cac thang 5, thang 6 va thing 10 am lich, hoat dpng khai thac ca thirdng difin ra vio 1^ nudc cudng img vdi nhiing ngay cudi thing 5, diu tiling 6 va cudi thang 10 am lich, luc nay ci dia con trdi vao rit nhieu. Sd lugng ca dia gidng khai thac dupc d Thuan An va Phu Thuan khoang 540.000 con, sd ci nay chu yeu dupc dua vao uong nudi. Ket qui didu tra ciia Trung tam Gidng thiiy sin tinh Thira Thifin - Hue ( 2007 ) cho thiy ci dia chi xuit hien thing &-lhing 8 am Uch va phirong phap rd cho hifiu qua khai thac cao hon do ca gidng thu dupc khde hon va sd lupng ca chdt it hon so vdi cac phuang phap khac. Theo kdt qua khao sat ciia Phan vien Hii dirong hpc Hii Phdng (2001) thi ca dia khdng de trong dim phi ma dim pha chl li ndi uong ip ci con thinh ca tiirdng thanh. Ci dia gidng phan bo theo mua va theo khu vuc rit rd rfit Ca dia {Siganus spp) con cd kich thudc 1,5-5 cm xuat hifin thang 3-9, chii yeu tap tnmg vao thing 3,4,5.
Ci kinh: ca kinh gidng thu dupc vdi sd lupng
rat ldn khoang 25.000.000 con. Qua thu miu cho thay ca xult hi^n vio thang 3 vi thing 4 am lich vdi kich thudc 1-3 cm/con, trong giai doan nay ca dupc khai thac chu ydu bang day, rd giin va nd sao. Tuy nhifin nhiing thing sau chung tdi ciing thu dupc gidng ci kinh vdi kich thudc ldn hon 5-7 cm do ci vio sdng mfit thdi gian trong dim. Vao mua thu vdt ca gidng, ngoai vific cung cip du con gidng phuc vu nudi trdng thuy san, gidng ca kinh cdn dupc ban de lam mim ca rd.
Ci mu. ci mu trdi vao dam pha vao cac thing 7,
thing 8 va thing 11 am lich, ngudi dan khai thac ca
lONG NGHIEP VA PHAT TRIEN N 6 N G T H 6 N - KY 2 - THANG 12/2014 113
gidng bing nghe rd, nghe day. Phuang phap khai thac ca mii gidng cd ldn (>20 g/con) chu yeu la nghd cau. Sd lupng ca mu gidng khai thac dugc rat it khoang 140.000 con. Chiing chi xuat hien a khu vyc gin cita phi, noi ma anh hudng ciia khdi nudc bien Ifin dam pha manh. Ca mu khdng smh s i n trong dim pha ma ca con trdi vao pha va tni ngu h-ong pha la nm sinh cu cua chung (Phan vifin Hai duong hpc Hai Phdng, 2001).
Ci nau. Nam 2013, ca nau vao dim pha d ciia bien Thuan An vao cudi thing 10 am hch, c i duoc khai thac bang nghd day, rd, nd (d cua bidn Tu Hidn ngudi dan danh bat bang each dat cac trd chuom) vdi kich cd bang hat dua, ngoai ra cd thd khai tiiac ca nau cd kich thudc ldn han. Sd lugng ca nau xuat hifin it hon so vdd nhiing nam trudc va it n h i t trong t i t ca cac loM c i gidng thu duoc, khoing 20.000 con, do vay sd lupng ca nau khfing dii dd cung cap cho ngudi nudi.
Ci ddi: kdt qua dieu tra cho thiy ca ddi gidng xuat hifin vao khoang thing 3, thing 4 am lich. Kdt qui khao sit cua Phan vifin Hai duong hpc Hai Phdng (2001) cho thay tan sd va sd lupng ca ddi d vung ciia Thuan An r i t ddi dao so vdi cac noi khic trong pha. Sy phan bd khac nhau nay cd le do tap tinh sinh hpc cua ca ddi la loai cd nguon gdc tir bien.
Giai doan tnrdng thinh tap trung thanh dan d bien de de. O giai doan con non va chua trudng thanh chung vao sdng d viing cua sdng va trong cac dim nudc lp. Kdt q u i khao sit cua Trung tam Gidng thuy sin tinh Thira Thifin - Hue vao thang 3 nam 2007 cho thiy c i ddi dupc khai thic b i n g nghe rd la chu yeu.
Sd lugng ca khai thac cua mfii mifing rd/ngiy dem (cd 6-8 lan cat rd) la 2.250 ± 360 con. Sd lupng ca gidng tuong ddi nhieu, bao gdm ca ddi la {Mugil kelearti) va ca ddi muc {Mugil cephalu^. Vao thdi didm c i ddi xuit hifin, ngudi dan nuoi trdng thuy san chi viec md cdng lly nudc vio ao nudi la cd the thu dupc ca ddi gidng.
- Ci hdng: xuit hien vao tiiang 7- thang 9 am lich vdi sd luong khoang 30.000 con du de cung cap gidng cho nudi trdng thuy san. Ca hdng dupc khai thac bang nghe day, nd sio, kich thudc 1-3 cm.
4. K ^ LUAN
Ngudi dan viing Thuan An v i Phu Thuan cua he dim p h i Tam Giang - Ciu Hai lam nghd khai thic c i gidng cd trinh dp hpc vin tuong ddi thip, chu ydu
mdi hgc het tidu hpc. Tuy nhifin hoat ddng khai thac c i gidng cua ngudi dan ven pha Tam Giang- Ciu ifej la nghd truydn thdng, cd tii iau ddi, ddng thdi nguoi dan cd rat nhidu kmh nghifim ti-ong nghd nay.
6 cira bidn Thuan An xac dinh cd 7 loai ca troi vio dim pha dd la ca dia, ca kinh, ca mu, ca nau, ci hdng, ca hanh va ca ddi.
Khai thac ca gidng chu ydu b i n g cac nghe day, nghd nd sao va nghe rd. Cac nghd niy sii dung lira cd kich thudc mat ludi r i t nhd 2a=2-4 mm.
Mua vu xuat hifin cac loii c i gidng vao cua hik Thuan An; ca dia thang 5- thang 6 va thang 10 am lich, ca kinh thing 2-thing 4 am lich, ca nau thang 10- thing 11 am lich, ca ddi thing 3 - thing 4 am lich, c i mu thang 7- thing 8 va thing 11 am lich, ca hdng thang 7- thang 9 am lich, ca hanh tiiang 8- thang 9 am lich.
Ca khai thac cd kich thudc 2-5 cm. Sd lupng ci khai thac nhidu n h i t la c i kinh (ci rd) 25.000.000 con, ca dia 540.000 con, c i mu 140.000 con, ca hanh 30.000 con, c i hdng 30.000 con v i ca nau 20.000 con.
TAI LIEU THAM KHAO
1. Nguyfin van Hio, 2001. C i nudc nggt Vi^
Nam. Tap III. NXB Nfing nghifip. Ha Ndi.
2. Nguyfin Hung, 2004. Vung dim phi ldn nhit Ddng Nam A dang kfiu ciiu. http://www.nea.gov.vn /nIndex.asp?ID=21346.
3. Le Van Mifin, Nguyfin Diic Phiic, Nguyfin V3n Khanh, Nguyfin Thi Thuy Hudng, Trin Van Son, Nguyfin Thifin Nam, Dang Phudc Binh, Nguyfin TTi]
Huong, Nguyfin Van Thai va Huynh Xuan Anh, 2005.
Thiet lap cdng thiic thuc nghifim dinh gii hem nang ngudn lgi thuy sin d dim p h i tinh Thira Thifin - Hue.
Ky yeu hgi thao qudc gia ve dim p h i Thira Thien - Hue, 2005, trang 400405.
4. Lfi van Mifin, 2006. Nhiing boat dpng dam pha d Thua Thien - Hue. Quan ly tdng hop cic ho^t dpng dim pha, Dy an IMOLA.
5. Phan vifin Hai duong hpc Hii Phdng, 2001.
Dieu tra khio sat bai gidng, bai de ciia hfi dim pha Thira Thifin - Hud va dd xuit c i c giai phap bao vfi.
6. Tnmg tam Gidng tiiuy sin tinh Thira Thidn- Hud, 2007. Khao sit nhanh tinh hinh dinh bit, miia vu dinh bit gidng, tinh hinh nudi v i mua vu nufli
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KHOA HOC C O N G NGHE
ndt sd loai ca kinh td d dim phi Tam Giang - Clu Hai- Tinh Thira Thifin - Hue, Blo cao chuyfin dfi.
COMPOSmON OF FISH FINGERLING SPECIES AND CURRENT STATUS OF FISH FINGERLING EXPLOITATION ATTHUAN AN ESTUARY IN TAM GIAN&CAU HAI LAGOON, PHU VANG DISTRICT,
THUA THIEN - HUE PROVINCE
Tran Thi Thu Suong^ Vo Due Nghia^
Summary
This study was conducted by a survey of 107 households which have been doing fish fingerlings exploitation at 'Hiuan An town and Phu Thuan commune during a 12-month period from January to December 2013. The study results showed that fish fingerlings was catched by bottom net, fish coral and fixed lift net. Most of the households have been catching fish fingerlings by pushing net in this area. However, the fingerlings quabty which were catched by pushing net was poor, which lead to high mortality during rearing period. Eight economical species was idenUfied at Thuan An estuary includmg siganids {Siganus guttatus, Siganus canaliculatui), groupers {Epinephelus coioidei), spotted scat {Scatophagus argus), snappers {Lutjanus spp), sea bream {Sparus latus) and flathead mullet {Mugil cephalus, Mugil kelearti). The number of Siganus canaUculatus was the highest, with approximately 25,000,000 fingerlings, this is followed by about 540,000 fingerlins of other sigamds, 140,000 fingerlmgs of grouper, about 30,000 sea bream fingerlings and 20,000 fingerlings of spotted scat. Additionally, the season of all fingerlings in Tam Giang lagoon, Thuan An town was from March to November Qunar calendar). During this penod, fingerlmgs with bigger size, approximately of 2-5 cm can also be observed in the lagoon.
Keywords: Fish dngerling, Ssh species composition, £sh Sngerling exploitation, seasonal, TTiuanAn estuary.
Ngudi phin bi^n: TS. Chu Tidn Vinh Ngiy nhan bii: 21/7/2014 Ngiy tiidng qua phan bifin: 21/8/2014 Ngiy duy^t dSng: 28/9/2014
Faculty of Fisheries, Hue university of Agriculture and Forestiy
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