Nghiên cứu Hiện trạng khai thác và phân phối tôm sú bố mẹ vùng biển phía Nam và Tây Nam đồng bằng sông Cửu Long được thực hiện nhằm cung cấp thông tin liên quan đến hiện trạng khai thác, phân phối tôm sú bố mẹ ở ĐBSCl, từ đó làm cơ sở cho việc quản lý, bảo vệ và sử dụng hợp lý nguồn tôm sú bố mẹ này.
202 Tuyen Up Hi»i nghj KHOA HQC T O A N Q U O C V £ SINH HQC BifeN VA P H A T T R I ^ N B £ N VLfNG HIEN TRANG KHAI THAC VA PHAN PHOI TOM SU (PENAEUS MONODON) BO ME VUNG BIEN PHIA NAM VA TAY NAM DONG BANG SONG CUU LONG Chau Tai Tao, Hoang Van Siiy, Tran Ngpc Hai va Nguyen Thanh Phirong Dai hoc Cdn Tha I M O DAU Ca Mau l i mot nhiing ngu trudng khai thic bien vao loai dirng diu ca nude, cd tiem nang ddi dao, vi viy ma nghe khai thac bien hien rit da dang va phong phu Khai thic tdm sii bd me hien cung la mpt nhirng nghe quan trpng, vira dem lai Igi nhuan cao cho ngu dan, vira gdp phan cung cap tdm bd me cho nghe sin xuit tdm gidng va nudi tdm d Ca Mau va Ddng bang Sdng Cim Long ndi chung Hien nay, ci nude cd khoang 4.281 trai san xuat ban 28,8 ti tdm gidng, dd, DBSCL cd tren 1200 frai v i sin lugng tren 11 ti tdm bdt cung cap cho nghe nudi (Bd Thiiy sin 2006) Trong sin xuit gidng tdm sii vin de quan trgng nhit la chit lupng tdm sii bd me la mgt nhiing nguyen nhan chinh se quyet djnh den sy cdng hay thit bai ciia trai sin xuat gidng Hien nay, hiu het cac trai sin xuit gidng deu phai le thudc vao ngudn tdm bd me khai thac ty nhien, mac dii mpt sd trai da sir dung ngudn tdm dam de nudi vd tdm bd me (Le Xuin Sinh, 2002) De dap img dugc nhu ciu dd thi nghe khai thic tdm su bd mp ngiy cing phat trien hon Hien tai cd rit it thdng tin ve tinh hinh khai thac va sir dung tdm sii bd me d DBSCL Chinh vi the, nghien ciru dugc thyc hien nham gdp phin cung cap thdng tin lien quan den hipn trang khai thic, phin phdi tdm sii bd mp d DBSCL lam ca sd cho quan ly, bio ve va sir dyng hgp ly ngudn tdm sii bd mp cho phat trien san xuat tdm gidng vi nudi tdm sii ben virng d Ci Mau ndi rieng va DBSCL ndi chung II PHI/ONG PHAP NGHIEN CLTU Dja diem va thdi gian nghien ciru Dieu fra ve hien frang khai thic vi phin phdi tdm su dugc thyc hien tai cua bien Rach Gdc, huyen Ngpc Hien, tinh Ca Mau tir nam 2007 din nam 2008 Sd lieu thir cip dugc thu thip tir cac bao cio ciia co quan ban nganh dja phuong va tram kiem djch thiiy sin tai Rach Gdc Sd lieu so cip dugc thu thap bang phuong phap phdng vin fryc tiep ngiu nhien cic tau khai thic (32 tiu), co sd thu mua tdm sii bd mp (23 dai ly cap va 13 dai ly cip II), sir dyng bang cau hdi da soan sin Cic thdng tin so cip chinh cin thu thip gdm ngu trudng, miia vy vi ngu cy khai thic, sd lugng tdm khai thic, each tieu thy, gia ban, tinh hinh phin phdi tdm su bd mp Cic sd lieu so cap va thir cip dugc cap nhit vi tinh toan gia frj trung binh, lech chuan, ldn nhat, nhd nhit vi phan tich dya tren phin mem Excel Tieu ban: TAI NGUYEN SINH VAT B I ^ N v A N G U O N LQl 203 HI KET QUA VA THAO LUAN San luong khai thac torn sii bo me 1.1 Sdn luang torn su bo me khai thdc qua cdc nam Theo Sd Thiiy sin Ca Mau (2006) bat diu tir thing 8/2006 thi tat ca tdm su bo me khai thic tir biln phai dugc kiem djch, sach benh mdi dugc dua vao frai san xuat gidng v i phin phdi cac tinh Sd lugng tdm sii bd mp khai thic dugc tang nhanh chdng qua cic nam dac biet li frong nam 2007 vi 2008 (hinh 1) Cu the nam 2008 sd lugng tdm sii bd mp khai thic dugc li 138.631 dd cd 101.409 tdm cai va 37.222 tdm dye Dieu niy vira phan inh nhu ciu ve tdm bo me cho cic trai gidng la rit ldn va ngiy cing cao, vira cho thiy boat ddng nang ddng ciia nghe khai thic Qua khio sit cho thiy nhirng nam trudc diy ngu din khai thic theo miia va theo nude thiiy trieu, cdn hien hp khai thic hiu nhu quanh nam Mgt diem rit quan trpng la ngu cy vi ky thuat khai thic tdm su bd me cing hien dai hon, ngu din khai thic ngiy cing nhieu do sin lupng tdm sii bd me tang cao qua cic nam Ket qui tren cung cho thiy ip lyc len ngudn lgi tdm bd me ty nhien cung cing ldn Hinh Sy gia tang san lu'O'ng torn sii b6 m? khai thac qua cac nam Theo Withyachumnamkul (2000) thi sy gia tang khai thic ngudn tdm sii bd me ngoai ty nhien fren toin the gidi de cung cip cho cac trai sin xuit gidng da lim giim di ngudn lgi tdm sii bo me ngoai ty nhien va gia tdm sii bd me tang cao lim inh hudng den hipu qua sin xuit cua cac trai gidng 1.2 Sdn luang torn su bo me khai thdc duac qua cdc thdng nam 2008 So lugng tdm sii bo me khai thic nam 2008 li rit Idn, cy thi la 101.409 tdm cii v i 37.222 tdm dye (hinh 2) Ngu din khai thac quanh nam nhung cic thing cd lugng tdm khai thac nhieu nhit la tir thing 11 din thing nam sau, dd thing cd sd lugng tdm khai thic Idn nhit li 12.868 tdm cii va 5.261 tdm dye cdn so tdm khai thic dugc it nhit la thing vdi 5.311 tdm cai va 1.634 tdm dye 204 Tuyen tJp HOi nghj KHOA HQC T O A N Q U C V ^ SINH HOC B I £ N V A P H A T T R I ^ N B £ N VCTNG 14000 12000 'S^IOOOO ^ 8000 I - (3000 a 4000 2000 Tliiutg 10 11 12 Hinh SIP bi4n 6gi\g san lu>(7ng tom sii bd mf khai thac nam 2008 Trong tdng sd tdm bd mp khai thac dugc tap trung tai Rach Gdc - Ca Mau nam 2008, so tdm bin cic tinh ngoai Ca Mau cd qua kiem djch la 13.410 tdm cai va 6.624 tdm dye, phin ldn tdm cdn lai dugc sir dyng cho cic frai gidng tinh Ca Mau Tinh hinh khai thac tom sii bo mf 2.1 Luc luang vd ngu trudng khai thdc Ket qua dieufracho thiy da sd dan khai thac tdm su bd mp den tir tinh Bac Lieu ma t^p trung 84% la ngu dan tir thj xa Bac Lieu va sd cdn lai nam rii rac d cic huyen Vmh Lgi (9%), Hda Binh (3%) va Hp Phdng (3%) Hipn ngu trudng khai thic tdm su bd mp chu yeu la vimg bien phia Nam va Tiy Nam DBSCL, noi cd dp sau khoang 30m vi nen day cat Theo Motoh (1981) thi tdm den tudi trudng di chuyen den bien siu cd den 162m, thudng la 2070m de sinh sin Theo Pomlerd et al (2005) thi khai thac tdm su bo mp d nhirng viing nude sach cd nen day cat xa bd, dp siu tir 30-60m thi thu dugc nhiing tdm cd chat lupng tdt va ngu cy bang ludi re cd the lam giam thieu xay sit dan tdm sii bd mp 2.2 Ngu cu vd miia vu khai thdc Loai phuong tien khai thac tdm bo mp chinh la cic tiu cd cdng suit tir 90 CV trd len vdi ngu cy khai thac la ludi re mang cd chieu dai trung binh 9.372±2.482m va chieu sau frung binh 3,3±0,5m vdi mat ludi ngoai ciing 2a la 28,3±2,4cm, mit ludi thin 2a la 8,6±0,8 cm Khi ludi dugc tha xudng bien thi cic mang se hinh tui ludi cd kha nang biy dugc nhieu kich cd tdm (80-300g/con) Hoat dgng khai thac tdm su bd me cua ngu din dien lien tuc cac thing Mdi ghe khai thac tha va thu ludi mpt lin/ ngay, thiiy trieu bit dau len cung la luc ngir din rii ludi va den thiiy trieu xudng thi tien hinh len ludi thu tdm Tdm su bd mp dinh bat thudng dugc thi vio thiing xop cd chay may syc chd cic ghe cua dai ly cap I thu gom va van chuyen vao dit lien Miia vu khai thic hien la quanh nam, nhung nang suit bien dgng theo miia hay thdi tiet va nhu ciu sir dyng tdm sii bd me tir cac trai gidng Tieu ban: TAI NGUYEN SINH VAT B | £ N V A N G U O N LO'I 205 Gia ban torn sii bo mf tai ngu trudng Qua kit qiia dieu tra 32 tau khai thic thi gii ban tdm cii tnmg binh li 709.375±588.250 d/con (biln ddng tir 150.000- 3.000.000d) va gii tdm dye frung binhli 34.063±18.608 d'con (tir 10.000-1 OO.OOOd) Gii tdm bd me phy thudc vio thi frudng, miia vu vi chit lugng tdm bd me Hien tai cira bien Rach Gdc cd 23 dai ly cap I vi 13 dai ly cap II thudng xuyen kinh doanh tdm su bd me dinh ky 2-3 mgt chuyen di tren bien va mpt vai co sd kinh doanh nhd le (khdng dang ky hinh nghe) 3.1 Kenh phdn phoi torn su bo me Nghe khai thic tdm sii bd me ciia C i Mau phit frien khoang tir nam 2003 v i noi cd boat ddng thi trudng mua bin tdm sii bd me sam uat nhit Ii cira bien Rach Gdc thudc xa Tin An, huyen Ngpc Hien Kenh phin phdi tdm sii bd me theo so dd sau: 3.2 Dgi ly cap I Dai ly Cip I dugc hieu li noi thu gom tdm bd me tir ngu din khai thac va mdi dai ly cd mgt hoac nhieu ghe (tir 1-3 chiec), hp cd cano vdi cdng suit Idn hoat ddng tren bien, chay ngu frucng mua tryc tiep tir ngu dan khai thic Hiu het cic ghe khai thic chi vao bd cin thiet nhu cic trudng hgp sira chira miy mdc, ngu cy hay ngu din dau dm benh tit Nhung nhu ciu khic nhu luong thyc, thyc phim, nhien lieu dugc mua tryc tiep tir cac ghe thu mua cua dai ly cip mang cung cip ngoii bien Sd chuyen cua cic tiu dai ly cip I bien thu gom tdm vio khoing 6±1 chuyen/thing (tir 3-18 chuyen/thang) vi lugng tdm mua trung binh 44±12 con/chuyen (25-70 con/chuyen) Nhu viy, trung binh mdi thing mpt tau thu mua dugc 162±63 (dao ddng tir 80-360 con/thing) Ngudn tdm bd me khdng dn djnh v i ngu trudng khai thic nam xa bd nen cac dai Iy cip I ludn tiic tryc thu gom va chuyen tdm ve Tdng sd tdm bd me mi mdi dai Iy cip I thu mua dugc trung binh li 4.277±3.604 con/nam (1.200-15.480 con/nam) Sd lugng tdm cii dugc dai Iy cip I cung cap cho cic trai gidng va dai ly cip II cung nhu nhirng ngudi mua khic frung binh li 3.343±2.934 con/nam (800-16.800 con) Sd lugng tdm dye dugc dai ly cap I phin phdi trung binh 935±702 con/nam (200-3.360 con) Nhu viy, sd tdm cii dugc dai Iy cip I phin phoi chilm 78%, v i tdm iuc Ii 22% Tdm me phan phdi tir cic dai ly cap I tryc tilp cho cac trai giong la 7.688 con/nam (10%) v i dai ly cip II trung binh 69.192 con/nam (90%) Trong nam 2007 thi tdng sd tdm bo mp ma tat ci cic dai ly cip I phin phdi khoang 98.375 con/nam dd tdm cii la 76.880 con/nam (78,15%) va tdm dye li 21.495 con/nam (21,85%) Gii frung binh mdi tdm cii 826.087±407.771 dong (tir 350.000-3.000.000d), tdm cii cd gia dudi mirc trung binh chung chiem 61% va fren mu:c trung binh chiem 39% Gii moi tdm dye tinng binh 78.043±32.604d (tir 30.000-200.000d), tdm dye cd gii dudi mirc trung binh chung chiem 48% va fren mirc trung binh chung chiem 52% •I I 206 Tuyen tgp H$i nghj KHOA HQC T O A N Q U Q C Vfe SINH HOC B I £ N V A P H A T T R I E N B £ N VCfNG "; N g u dan khai t h a c i Dai ly cap thu g o m tren bien •i Dai ly c a p Trai gidng tinh (Ck Mau) Trai giong c i c tinh lan can (Chu yeu la Mien Trung) Hinh Sa dd kenh phan phoi torn su bd mf 3.3 Dgi ly cap II La CO sd thu mua tir dai ly cap I de ban cho cac frai gidng hoac phan phdi di cac dja phuang khac d DBSCL, cho cac thuang Iii va cho cac co sd sin xuit tdm gidng d mien Trung Dai ly cap n la noi thu mua tdm phin phdi chu yeu ngoii tinh nen thudng thu tdm cd nhieu ngudn gdc va nudi giir lai vdi mat tuong ddi day, dieu niy lam tang nang liy nhiem benh ciia tdm bo mp Sd lugng tdm cii dugc dai ly cip II cung cip cho cic frai gidng va cac td chirc ca nhin khac cd nhu ciu trung binh Ii 5.785±4.036 con/nam (tir 1.650-13.500 con/nam) Sd tdm cai dugc phin phoi ngoai tinh la 4.57I±3.706 con/nam chiem 73,3% vi tinh la 1.213±779 con/nam chiem 26,7% So tdm dye trung binh la 1.596±1.133 con/nam (325-3.500 con/nam) Lugng torn' bd mp cua tat ca cac dai ly cap II cung cap la 88.538 con/nam, tdm cai 69.192 con/nam (78,15%) vatdm dye 19.346 con/nam (21,85%) Gii bin tinng binh 1.321.145d/tdm cai (tir 600.000-2.400.000d/con) va 109.615 d/tdm dye (100.000-125.000d/con) Tdm cai cd gia dudi mirc trung binh chiem 46% va tren mirc trung binh Ii 54%, ddi vdi tdm dye ty lp lan lugt la 62%vi38% TV KET LUAN Sin lupng tdm sii bo me khai thic dugc tang nhanh nhirng nam gin diy va miia vv khai thic hiu nhu quanh nam nhien sin lugng bien ddng theo cac thing nam Trong nam 2007 thi dai ly cip mpt thu gom vi phin phdi lai cho dai ly cip hai va cac trai gidng Ii 76.880 tdm cii vi 21.495 tdm dye vdi gii ban trung binh la 826.087±407.771 ddng/tdm cii vi 78.043±32.604 ddng/tdm dye Trong dd thi dai ly cip hai phan phoi dugc 69.192 tdm cii va 19.364 tdm dye vdi gii ban Ii 1.321.154±576.795 ddng/tdm cii vi 109.615±12.659 ddng/tdm dye Nim 2008 khai thic dugc 101.409 tdm cii vi 37.222 tdm dye Trong sd niy, tdm ban ngoii tinh Ca Mau cd qua kiem djch la 13.410 tdm cii vi 6.624 tdm dye, phin Idn tdm cdn lai dugc sir dung cho cic frai gidng tinh Tilu ban: TAI NGUYEN SINH VAT BI^N VA N G U Q N LQ'I 207 V TAI LIEU THAM KHAO Bd Thiiy sin 2006 Bio cio dinh gii ket qui thyc hien chuong trinh phit triln NTTS giai doan 2000-2005 va bipn phap thyc hien din nam 2010 Ha Ngi, thing nam 2006 Le Xuan Sinh 2002 Tdm bd me sir dyng frong frai sin xuit gidng Tap chi Thuy sin so 6, 2002 Bp Thiiy sin, tr.l 1-14 Motoh 1981 Aquaculture Deparment Southeast Asian Fisheries Development Center, Iloilo, Philippine Pomlerd, Chanratchakool, Flavio, Corsin and Matthew Briggs, 2005 Hudng din thyc hanh quan ly tdt (BMP) frong trai san xuat tdm sii gidng tai Viet Nam Bp Thiiy sin Viet Nam phoi hgp thyc hien, thing 12 nam 2005 Sd Thiiy sin Ca Mau, (2006) Mpt sd vin de khai thac, quan ly tdm bd me vi sin xuit gidng tdm sii tai chd d Ca Mau Hgi nghj ban ve giai phap phat trien nudi thiiy sin ben vimg cic tinh Nam Bd Withachumnamkul B, P Plodphai, G Nash and D Fegan 2000 Performances of domesticated Penaeus monodon broodstock in Thailand Asian Aquaculture Magazine, March/ Apnl 2002 EXPLOITATION AND DISTRIBUTION OF TIGER SHRIMP (PENAEUS MONODON) BROODSTOCKS THE SOUTH AND SOUTH - WEST SEA OF THE MEKONG DELTA Chau Tai Tao, Hoang Van Suy, Tran Ngoc Hai, Nguyen Thanh Phuong SUMMARY Demands on wild tiger shrimp (Penaeus monodon) broodstocks for seed production in Vietnam are increasing rapidly Rach Goc river mouth of Ngoc Hien District, Ca Mau province is considered the main place for gathering shrimp broodstocks from fishing boats in the South and South-West sea of the Mekong Delta and then distribute for seed production on the regional provinces and the cenfral provinces This study aims at evaluation of fishing and distribution of tiger shrimp broodstocks in order to contribute to resources management in the region Secondary data were collected from the fisheries station in Rach Goc and primary data were collected from interviewing 32 fishermen, 23 first distributors and 13 second distributors based on prepared questionairs Results of the study showed that the fishing ground of tiger shrimp broodstocks are in the South and South - West of the Mekong Delta with sandy bottom and water deptii of about 30m Fishermen are mainly from Bac Lieu province Fishing boats have high capacity of over 90CV and use drag net as fishing gear Fishing season is year round, however, production is seasonal Number of broodstocks exploited has been increasing rapidly, from totally 40,000 shrimps by 2003 to 101,409 female and 37,222 males by 2008 Of this number, number of shnmp broodstocks checked for diseases and sold to regional provinces is 13410 female and 6624 male broodstocks, the most of broostocks are supplied to the hatcheries in Ca Mau province Average body weight of the female is 160±14.5g and the male is 96.1±8.30 g Average selling pnce at 208 Tuyln tap HQi nghj KHOA HQC T O A N Q U Q C V t SINH HOC BI^N VA P H A T T R I ^ N B S N VCTNG fishmg ground is 709,375±588,250 VND/female shrimp and 34,063±18,608 VND/male shrimp.' By the year 2007, the first distributors sold to the second distributors and the hatchery owners totally 76,880 female and 21.495 male at average price of 826,087±407,771 VND/female ancj 78,043±32,604 VND/male Meanwhile, the second distributors sold the broodstocks at 1,321,154±576,795 VND/female and 109,615±12,659 VND/male Generally, exploitation and supply of wild shrimp broodstocks are very importance for shrimp hatchery production in the Mekong Delta However, this study is calling for more studies to develop appropriate methods of fishing and conservation while still ensure the development of shrimp seed production in the region ^ Keywords: Black tiger shrimp, brood-stock, male, female, fishing '' | d fMl£ •Vi -.i -/) A ... torn su bo me khai thdc duac qua cdc thdng nam 2008 So lugng tdm sii bo me khai thic nam 2008 li rit Idn, cy thi la 101.409 tdm cii v i 37.222 tdm dye (hinh 2) Ngu din khai thac quanh nam nhung cic... LUAN Sin lupng tdm sii bo me khai thic dugc tang nhanh nhirng nam gin diy va miia vv khai thic hiu nhu quanh nam nhien sin lugng bien ddng theo cac thing nam Trong nam 2007 thi dai ly cip mpt... cac tinh Sd lugng tdm sii bd mp khai thic dugc tang nhanh chdng qua cic nam dac biet li frong nam 2007 vi 2008 (hinh 1) Cu the nam 2008 sd lugng tdm sii bd mp khai thic dugc li 138.631 dd cd