Nguồn lợi tôm vùng biển ven bờ phía Tây vịnh Bắc Bộ

286 Tuyen tgp HQi nghi KHOA HOC T O A N Q U O C Vfe SINH HQC BI^N vA P H A T TRI^N SgN VCTNG<br /> <br /> <br /> <br /> <br /> NGUON LOI TOM VUNG BIEN VEN BOf P H U TAY VINH BAC BQ<br /> <br /> Mai Cong Nhuan, Doan Van Du, Nguyen Cong Con<br /> Viin Nghien cuu Hdi sdn. Bp Nong nghiip vd Phdt triin nong thon<br /> <br /> <br /> 1. M O DAU<br /> Vimg bien Vjnh Bic Bp phia ddng gidi han bdi dudng ranh gidi frong hifp djnh sa bp Vift<br /> Trung, phia Nam la dudng vT tuyln 17°30. Nam trong vimg nhift ddi gid mua, vjnh Bac Bp la<br /> vimg bifn cd thinh phin loai rit da dang v i phong phii vdi 960 loai hai sin da dugc xic djnh,<br /> trong do cd 58 loii tom (Vu Vift Ha, 2003)<br /> Da CO nhieu chuong trinh nghifn curu ve nguon lgi hii sin d vjnh Bac Bp. Tuy nhifn cic<br /> nghien cun chu yeu tip chung vio nguon lgi ca bien. Nghien ciiru ve tdm bifn cdn chua dugc<br /> quan tam. Ding chii y nhat la chuang trinh difu tra ngudn lgi tdm d vimg bifn ven bd phia tiy<br /> Vjnh Bic BpfrrMong Cai din Cira Sot (Ha TTnh). Trong giai doan 1975 - 1978. De tai dilu fra<br /> tom giong ven bd vimg bien Hii Phong - Thanh Hoi tir nam 1986 -1990 va de tai kifm fra sin<br /> lupng mpt so cac bai tom nam 1993. Trong hai nam 2002 va 2003, Dy an "Danh gia nguon lgi<br /> sinh vat bien Viet Nam" giai doan II (2000 - 2005) da den hinh bdn chuyfn khao sat ngudn Igi<br /> tom theo hf thong tram thift ke co djnh bao phii tir dg sau < 30 m nude trd vao. Npi dung bai<br /> viet niy trinh biy cic ket qua nghifn cuu ve thanh phin loii, nang suat khai thac va trir lugng<br /> ciia cic hp tom bat gap d vimg bifn ven bd vjnh Bac Bp.<br /> <br /> n . TAI LIEU VA PHU'ONG PHAP<br /> <br /> L Tai lifu nghien ciru<br /> Tii lifu sii dung frong bai bio dugc thu thap bdi dy an "Dinh gia ngudn Igi sinh vat biln<br /> Vift Nam" giai doan 11. Gidi han frong khoing 21^45 -19^00' v i tir 30m frd vao (Hinh 1). Tong<br /> sd 4 chuyen dieu tra vdi 159 me ludi da dugc thyc hien d cac thing 4 va 9 nam 2002 va 2003.<br /> Ngu cy su dyng li ludi keo day tom cd chifu dai gifng phao 32m va kich thudc m i t ludi d dyt<br /> 2a=22mm. Cic me ludi dugc thyc hifn vio ban dem, thdi gian keo ludi frung binh la 1 gid, toe<br /> dp keo ludi trung binh khoing 2,2 hai ly/gid.<br /> Toan bp sin lugng cua me ludi dugc phin loai den loai (hoac nhom loai). Sd lugng ca the<br /> vi khoi lugng cua timg loii/nhdm loai dugc cin, dfm va ghi chep. Trong frudng hgp sin lugng<br /> me ldn, vifc lay mau phy df phan tich thanh phan loai dugc tiln hanh. Vifc lay mlu phy dugc<br /> tuan thii theo nguyen tic lay mau ngau nhien, dim bio dai difn cho toan bp san lugng.<br /> <br /> 2. Phuong phap nghien cuu<br /> <br /> 2.1. Thdnh phan lodi<br /> Thanh phan loai dugc djnh Ioai va ghi chep fren bien tai moi tram nghifn ciiru. Ngoai ra con<br /> thu miu ve v i phin tich frong phdng thi nghifm trong trudng hgp chua dii dilu kifn phan tich<br /> dugc tren hifn trudng.<br /> Ti^u ban; T A I NGUYEN SINH VAT B I £ N V A N G U O N LQI 287<br /> <br /> <br /> 2.2. Ndng sudt khai thdc<br /> Nang suit khai thic CPUE (sin lugng dinh bat cho mot gid keo ludi, kg/h) dugc tinh cho<br /> timg me ludi, timg loii (Sparre and Venema, 1998).<br /> <br /> ta<br /> Nang suat khai thac trung binh tinh theo cdng thuc: CPUE(kg I h) = — [1]<br /> <br /> 10B' 107- 108'<br /> 22<br /> <br /> <br /> <br /> <br /> 21<br /> <br /> <br /> <br /> <br /> _. Thanh Hoi<br /> <br /> <br /> <br /> <br /> 105" 106 107- 108' 109'<br /> <br /> <br /> <br /> Hinh 1. Sa dd tr^m vj cac chuyin dl§u tra<br /> <br /> <br /> <br /> <br /> 2.3. Mat dp phdn bo<br /> Mat dp CPUA (kg/km") dugc tinh cho timg fram, hing loai. CPUA dugc tinh toin theo<br /> phuang phap difn tich (Swept Area Method) (Sparre and Venema, 1998)<br /> , y CPUA, r-71<br /> Mat do trung binh tinh theo cong thuc: CPUAXkglkm')^^ L^J<br /> Trong dd: Ci la nang suit dinh bit trung binh ciia me ludi (kg); v la van toe keo ludi; h la<br /> chifu dai gilng phao; t li thdi gian keo ludi; n so tram.<br /> 288 Tuyln tSp HiJi nghj KHOA HQC T O A N Q U O C V t SINH HOC BI^N VA P H A T TRigN B £ N VLTNG<br /> <br /> <br /> <br /> 2.4. Trir luang<br /> Tru- lugng tom d vimg bifn nghifn cuu dugc tinh theo cdng thuc:<br /> B =CPUA .A/g [3]<br /> Trong do: B li trir lugng; A la difn tich vimg bifn nghien cuu; cPUA la mat dp phan bo<br /> tnmg binh vi q li hf so thoit ludi (q = 0,5) Hf s6 thoit ludi 0,5 dugc sir dyng frong udc tinh trir<br /> lugng ngudn lgi (Sparre and Venema, 1998).<br /> <br /> m . KET QUA NGHIEN CUtJ<br /> <br /> L Thanh phan loai<br /> Qua cic chuyin dilu fra frong cic nam 2002, 2003 da bat gap 36 loii/nhdm loai tdm nam<br /> frong 15 giong thupc 6 hp. Hp Tom He (Penaeidae^ cd so lugng loai bat gap nhieu nhat - 21 loai,<br /> tilp theo la hp Tdm Tit ('Squillidae^ bit gap 8 loai, hp Tom Vo ("Scyllaridaej bit gap 3 loai, hp<br /> Tdm Gai (Palaemonidae) bat 2 loai, hp Tdm tit (Harpiosquillidae) bat gap 2 loai va hp Tdm Lira<br /> (Solenoceridae) chi bat gap 1 loai.<br /> <br /> <br /> Bang 1. Sd hp, gidng, lodi torn b i t g^p qua cac chuyin d i l u tra<br /> Chuy§n di§u tra SdhQ S6 g i d n g Sd loai<br /> Thang 4/2002 4 8 15<br /> T h i n g 9/2002 5 10 22<br /> T h i n g 4/2003 5 11 24<br /> T h i n g 9/2003 6 13 29<br /> Chung 6 15 36<br /> <br /> <br /> <br /> <br /> Harpiosquillidae<br /> Squillidae ( T 6 m Tit), 3%<br /> (Tflm Tit), 22% Palaemonidae<br /> (T6m Gal), 6%<br /> <br /> Solenoceridae<br /> . ( r a m Lira), 3%<br /> <br /> <br /> <br /> V,<br /> Penaeidae<br /> Scyllaridae (T6m He) 5SV.<br /> (TSm V6), 8%<br /> <br /> <br /> <br /> <br /> 1<br /> Hinh 2. Ty If thanh phSn Ceic lodi tdm b i t gap qua cac chuyin d i l u tra t^i viing bien ven<br /> bd vjnh Bdc BQ<br /> Tj^u ban: TAI NGUYEN SINH VAT BifeN vA N G U O N LOI 289<br /> <br /> <br /> Bang 2. Danh sach cac loai tdm gap trong cac c h u y i n d i l u tra t^i viing b i l n ven b d phia<br /> tay vjnh Bac Bp<br /> <br /> TT Ten ho Ten loai<br /> 1 Harpiosquillidae - Hp Tom Tit Harpiosquilla annandalei - Tom Tit<br /> 2 Harpiosquilla sp. - Tom Tit<br /> 3 Palaemonidae - Hp Tom Gai Exopalaemon sp. - Tom Gai<br /> 4 Penaeidae - Hp Tom He Melapenaeopsis barbata - Tom Sat<br /> 5 Melapenaeopsis dalei - Tom Sat<br /> 6 Melapenaeopsis lamellala -Tom Sat<br /> 7 Melapenaeopsis sp. - Tom Choing<br /> 8 Melapenaeopsis tenella - Tom Sat<br /> 9 Metapenaeus affinis - Tom bop (Chi)<br /> 10 Metapenaeus ensis - Tom rao (Dit, Chi long)<br /> 11 Metapenaeus intermedius — Tom Duoi xanh<br /> 12 Metapenaeus Joyneri - Tom Ving<br /> 13 Metapenaeus sp. - Tdm Bop, (Chi, Rio)<br /> 14 Parapenaeopsis hardwickii - Tom Sat cirng (Choing)<br /> Parapenaeopsis hungerfordi - Tom Sit hoa (Mat<br /> 15 fre,Choing)<br /> 16 Parapenaeopsis sp. - Tom Sit (Giang)<br /> 17 Parapenaeopsis tenella - Tom Sit (Tom Choing)<br /> 18 Penaeus Japonicus - Tom He Nhit Bin (The bong)<br /> 19 Penaeus merguiensis - Tom He miia (The, Bac, Lot)<br /> 20 Penaeus monodon - Tom Su<br /> 21 Penaeus semisulcatus - Tom He van (The rin)<br /> 22 Trachypenaeus curviroslris - Tom Danh<br /> 23 Trachypenaeus longipes - Tom Gay, Tom Giang<br /> 24 Trachypenaeus sp. - Tom gay di, Tom Giang di<br /> TT Ten ho Ten loai<br /> 25 Scyllaridae - Hp Tom Vo Scvllarus martensii - Tom Vo<br /> 26 Scyllarus rugosus - Tom Vo<br /> 27 Tliemis orientalis - Tom Vo dep tring<br /> 28 Solenoceridae - Tom Lira Solenocera sp. - Tom Lira<br /> 29 Squillidae - Ho Tom Tit Anchisquilla fasciata - Tom Tit bp ngua<br /> 30 Carinosquilla carinala - Tdm Tit<br /> 31 Carinosquilla mullicarinala - Tom Tit munticari<br /> 32 Miyakaea nepa - Tom Tit<br /> 33 Oralosquilla gravieri - Tom Tit<br /> 34 Oralosquilla oratorio - Tom Tit<br /> 35 Oralosquilla perpensa - Tom Tit<br /> 36 Squilla sp. - Tom Tit<br /> 290 Tuyln t$p HQI nghj KHOA HOC T O A N Q U 6 C Vfe SINH HQC BI^N VA P H A T T R I ^ N B ^ N VLTNG<br /> <br /> <br /> <br /> 2. Nang suat khai thac (CPUE)<br /> Nang suat dinh bat trung binh chung cua cic hp Tom dao dpng tir 0,3 - 0,6kg/h (Bing 3).<br /> Nang suit danh bat trung binh ciia cic hp tom it co sy bifn dpng qua cic chuyen dieu tra. Hp<br /> tdm He (Penaeidae) cd nang suit danh bat cao nhat dao dpng frong khoing 0,8 - l,9kg/h, tiep<br /> theo la Hp tom Tit (Squillidae) dao dpng tir 0,4 - 0,6kg/h, hp Tom Lira (Solenoceridae): 0,1 -<br /> 0,5kg/h. hp Tdm vo (Scyllaridae) co nang suit dinh bat thap nhat khoing 0,001kg/h.<br /> <br /> Bang 3. Nang s u i t ddnh b i t trung binh (kg/h) cua cac hp tdm trong c i c chuyin d i l u tra<br /> nam 2002 - 2003 tf! vijng b i l n phia tay vjnh Bdc BQ<br /> H9 tom Chuyin dilu tra<br /> Thang 4/02 Thing 9/02 Thing 4/03 Thing 9/03<br /> Harpiosquillidae (TomTit) 0,3 0,3<br /> Palaemonidae (Tom Gai) 0.0 0,1 • 0,0 0,1<br /> Penaeidae (Tom He) 1.6 0,8 1,3 1,9<br /> Scyllaridae (Tom V5) 0,01 0,01<br /> Solenoceridae (Tom Lira) 0.1 0,1 0,1 0,5<br /> Squillidae (Tom Tit) 0,5 0,4 0,6 0,4<br /> Trung binh 0.6 0,3 0.4 0,5<br /> <br /> <br /> <br /> Harpiosquillidae<br /> Squillidae (T6m Tit) 9%<br /> (T6m Tit) 19%<br /> Palaemonidae<br /> (tdm Gal) 2%<br /> Solenoceridae<br /> ( T6m Li>a) 7%<br /> <br /> <br /> <br /> <br /> Scyllaridae J<br /> (T6m V6) 1%<br /> Penaeidae<br /> (T6m He) 63%<br /> <br /> <br /> <br /> <br /> Hinh 3. Ty l§ % san lu'O'ng cua c i c hp tdm b i t g^p trong cac chuyin d i l u tra nam 2002 -<br /> 2003 t^i vLing biln phia tay vjnh Bic BQ<br /> Ty If % sin lugng ciia cic hp tdm bat gap frong cic chuyfn difu tra tai vimg bifn ven bd<br /> Vjnh Bic Bp dugc trinh biy d hinh 2. Hp Tom He (Penaeidae) chifm sin lugng cao nhat, trung<br /> binh khoing 63%, tifp dfn la hp Tom Tit (Squillidae) 19%, hp Tom Tit (Harpiosquillidae) 9%.<br /> Hp Tdm Vo (Scyllaridae) chifm ti If sin lugng thap nhat.<br /> Thinh phan sin lugng tom khai thic co su bifn dpng qua cic chuyin dieu tra. Cd 9 loai<br /> tom chiem uu thf frong sin lugng khai thac cua cic chuyin biln thupc cic giong:<br /> Metapenaeopsis vi Trachypenaeus. Mpt so loii/nhdm loii tom chiem ti If sin lugng cao frong<br /> sin lugng khai thic dugc trinh biy d bing 4.<br /> Ti4u ban: TAI NGUYEN SINH VAT BI^N VA N G U O N i g i 291<br /> <br /> <br /> Ket qui nghien cuu cung cho thay cic loai thupc hp torn He (Penaeidae) thudng chilm ti le<br /> dudi 1% frong tong sin lugng danh bat.<br /> <br /> Bang 4. Ty I9 % s i n Iu'p'ng cac loai tdm cd san Iu'p'ng cao > 1% b i t g^p trong cac chuyin<br /> dilu tra nim 2002 - 2003 tai viing biln phia tay vjnh Bic Bp<br /> Chuyin dilu tra<br /> STT Ten ioai Thing 4/02 Thang 9/02 Thing 4/03 Thang 9/03<br /> 1 Harpiosquilla annandalei - - 1,55 1,94<br /> 2 Metapenaeopsis sp. 14,18 3,76 - 2,25<br /> 3 Metapenaeus affmis - - - 1,74<br /> 4 Trachypenaeus curviroslris - - 2,87 1,12<br /> 5 Trachypenaeus sp. 2,18 2,58 - 4,85<br /> 6 Solenocera sp. - 1,54 - 2,45<br /> 7 Anchisquilla fasciata - 0,56 - -<br /> 8 Oratosqullla gravieri - - 3,73 1,69<br /> 9 Squilla sp. 3,96 1,01 - -<br /> Tong 20,32 9,45 8,15 16,04<br /> <br /> 3. Mat do phan bo<br /> Mat dp phan bd frung binh cua cic hp tdm qua cac chuyfn dieu tra dugc trinh bay frong<br /> bing 5. Mat dp trung binh ciia cic hp tdm cd su bien dpng theo chuyfn difu tra, mat dp trung<br /> binh ciia chuyfn thing 4/2002 v i chuyen thing 4/2003 udc tinh khoing 0,09tin/km^ Mat dp<br /> phan bo cua cic Hp tdm trong chuyen thing 9 nam 2002 thap ban, udc tinh khoing 0,06<br /> tan/km^. Ket qui khio sit d chuyen thing 9 nam 2003 cho thay mat dp phan bo ciia cic hp tdm<br /> tang len, trung binh khoing 0,14 tan/km". Hp tom He (Penaeidae) co mat dp cao nhat dat 0,06<br /> tin/km^ tiep theo li hp tdm Tit (Squillidaej va hp Tdm tit (Harpiosquillidae); Hp Tom Vd<br /> (Scyllaridae) dfu cd mat dp thip - 0,001 tan/km'. Ngu trudng phan bo mat dp ciia cic hp tom the<br /> hifn d hinh 3. Khu vuc phan bo mat dp trung binh cao ciia chuyen khio sit thing 4 nam 2002 va<br /> nam 2003 chu ylu tap trung d khu vyc phia tren Quing Ninh (hdn Mit) va khu vuc phia ngoai<br /> Thii Binh - Nam Djnh trong dii dp siu 30m. Mat dp phan bo tip trung tmng binh ciia chuyen<br /> thing 9 nam 2002 va nam 2003 cd xu huong phan bd cao d khu v\rc ven bd trong dii dp sau<br /> 20m va phia fren Mdng Cii.<br /> <br /> Bing 5. TA^t dp dinh bit CPUA (tin/km^) cua c i c hp tdm trong cic chuyin dilu tra n i m<br /> 2002 - 2003 t^i vung biln phia tay vjnh Bic Bp<br /> H9 torn Chuydn di6u tra<br /> <br /> Thing Thing Thing 4/03 Thing 9/03 Trung binh<br /> 4/02 9/02<br /> Harpiosquillidae 0,01 0,01 0,01<br /> Palaemonidae 0,00 0,00 0,00 0,00 0,00<br /> Penaeidae 0,07 0,03 0,05 0,08 0,06<br /> Scyllaridae 0,00 0,00 0,00<br /> Solenoceridae 0,00 0,01 0,00 0,02 0,01<br /> Squillidae 0,02 0,02 0,03 0,02 0,02<br /> T6ng 0,09 0,06 0.09 0,14 0,09<br /> Ghi chii: 0,000 la nho han 0,001<br /> 292 Tuyen t$p H$i nghj KHOA HQC T O A N Q U O C V £ SINH HQC BI^N VA P H A T TRifeN B £ N VLTNG<br /> <br /> <br /> <br /> <br /> Phin bd CPUA tin/km cua c i c hp tdm Phan bd CPUA tin/km cua c i c hp torn<br /> trong t h i n g 4 n i m 2002 va n i m 2003 trong t h i n g 9 n i m 2002 va nam 2003<br /> <br /> <br /> Hinh 4. Mat dp phan bd cua c i c hp tdm qua c i c chuyen dieu tra t^i viing b i l n ven biy phia<br /> t i y vjnh B i c Bp<br /> <br /> <br /> 4. Trir lugng<br /> <br /> Tong trii- lugng torn d khu vuc phia tay vjnh Bac Bp tir 30m nude frd vao udc tinh khoing<br /> 2723 tin trong miia gid TN 2002 vi 1696 tan trong miia gio DB 2002. Con so niy dat 2773 tan<br /> frong miia gio TN 2003 va 4.048 tin frong miia gio DB 2003. Trong do, hp tom He (Penaeidae)<br /> dat sin lugng cao nhat qua tit ci cic chuyfn difu fra (6991 tan); tiep dfn li ho tdm Tit<br /> (Squillidae) 2275 tan; cic hp tom khic cd trir lugng thip (bing 6)<br /> <br /> B i n g 6. Trip Iu'p'ng (tin) u'O'c tinh cua c i c hp tdm bien b i t g | p trong c i c chuyin d i l u tra<br /> t^i vung b i l n vjnh B i c Bp<br /> <br /> Chuyen dieu tra<br /> Hp torn Thing 4/2002 Thing 9/2002 Thing 4/2003 Thing 9/2003 Trung binh<br /> Harpiosquillidae - - 339,3 416,8 378.05<br /> Palaemonidae 21,4 90,2 14,9 95,0 55,37<br /> Penaeidae 2014,1 982,1 1581,5 2414,0 1.747,92<br /> Scyllaridae - 1.3 1 11,1 6,2<br /> Solenoceridae 129,8 167.6 77,3 608,8 145,87<br /> Squillidae 557,9 455,0 i 759.7 502,5 568,77<br /> Tong 2.723,2 1.696,3 j 2.772.7 4.048,3 2.810,12<br /> Tieu ban: TAI NGUYEN SINH VAT BI^N VA N G U 6 N LOI 293<br /> <br /> <br /> <br /> 5. Thao luan<br /> Theo kit qui dieu tra ciia Vifn nghien ciru Hii sin tir nam 1975 - 1988, khu vuc gan bd<br /> phia tay vjnh Bac Bp tir dp siu 30m nude trd vao co 9 bai torn co mat dp torn He tap trung cao<br /> nhu: Bai torn My - Mieu, bai tom vinh Bai Tir Long, bai torn vinh Ha Long, bai torn Cit Ba -<br /> Cira Ba Lat, bai tom Hdn Ne - Lach Ghep, bai tom Lach Bang - Lach Quen, bai tom Vjnh Dien<br /> Chau, bai tom Cira Hpi - Cira Sdt (Vifn nghien ciru Hii sin, 1975).<br /> Trong miia gio Tiy Nam, mat dp trung binh cua hp torn He (Penaeidae) d vimg ven bd phia<br /> tay vjnh Bac Bp khoing 108kg/km^ Trpng diem tir Diem Dien den Tri Ly trung binh dat<br /> 300kg/km^ vao thing 11 va thing 1 dat 500kg/km^. Trpng diem tir Lach Bang - Lach Quen dat<br /> 400kg/km^, rieng thing 11 v i thing 3 dat 600kg/km^. Ngoii ra d khu vuc nay con co tdm Vo<br /> (Thenus orientalis) co mat dp khoing 62kg/km^(Pham Ngpc Dang, 1995).<br /> Trong miia gio Ddng Bac, mat dp trung binh ciia tom He (Penaeidae) d vimg ven bd<br /> phia tay vinh Bac Bp trung binh dat 85kg/km^. Bai torn Cit B i dat tren 600kg/km^, bai tom<br /> Bii Tir Long dat 200 - 300kg/km^ trong thing 4, 5 v i bai tom My - Mieu dat 300kg/km^<br /> frong thing 5. Ngoii ra sin lugng tom Vo (Thenus orientalis) cd mat dp dat 49kg/km" (Pham<br /> Ngpc Ding, 1975).<br /> So sinh ket qui tom he giai doan 1975 - 1980 vdi ket qua dieu tra giai doan 2002 - 2003.<br /> thiy rang, mat dp trung binh viing ven bd phia tay vjnh Bac Bp trong nhung nam 2002 - 2003 da<br /> bj giim silt chi cdn 55% frong miia gid Tay Nam v i 65% trong miia gid Dong Bac.<br /> Trong qui trinh dieu tra khdng phit hifn dugc bai tom frpng diem nio cd mat dp tom He<br /> tap trung cao nhu trudc diy (Pham Ngpc Dang. 1975). Loai tom vo bien siu (Thenus orientalis)<br /> tuy bat gap nhung mat dp rat thap khoing lOkg/km^ chi con khoing 16 - 20% so vdi mat dp<br /> trung binh nam 1975-1978.<br /> <br /> IV. KET LUAN<br /> • Trong cic chuyen dieu fra trong nam 2002 va 2003 d vimg bien ven bd phia tay vjnh Bac<br /> Bp da bat gap 36 loii/nhdm loii nam trong 15 giong thupc 6 hp tdm bifn.<br /> • Ning suit dinh bat trung binh ciia cic hp torn thap, dao dpng trong khoing 0,3-0,6kg/h ,<br /> tuong img vdi mat dp phan bo trung binh khoing 0,06 - 0,14 tan/km^. Hp Tom he chiem uu<br /> the ci vf thinh phin loii v i sin lupng khai thic cua cic chuyfn bifn.<br /> • Mat dp trung binh cua cac hp tom theo cic chuyen dieu tra: Thing 4/2002 - 0,09 tin/km^;<br /> thing 9/2002 - 0,06 tin/km^ thing 4/2003 - 0,09 tin/km^; thing 9/2003 - 0,14 tin/kml Hp<br /> torn He (Penaeidae) cd mat dp cao nhit frong 6 hp tdm dat 0,06 tin/km^.<br /> • Trir lugng tom d vimg bien ven bd vinh Bic Bp bien dpng manh giira cic chuyfn difu tra,<br /> udc tinh khoing 1,7 den 4,1 ngan tin, trung binh khoing 2,8 ngin tin. Hp tom he co trir<br /> lugng cao nhit, udc tinh khoing 1,7 nghin tan, chiem 60% tong trtr lugng tom d vimg bien<br /> ven bd phia tay vjnh Bac Bp.<br /> <br /> <br /> V. TAI LIEU THAM KHAO<br /> 1. Pham Ngpc Dang. 1990: Bio cio tom tit df tii "Dieu tra su phan bo va bien ddng nguon<br /> lgi tom gidng viing ven bifn v i cira sdng tir Hii Phong dfn Thanh Hoi"<br /> 2. Pham Ngpc Dang, Nguyen Cong Con. 1995: Bio cio tinh hinh nguon lgi Tom v i Muc bifn<br /> Viet Nam, hien trang vi cic bien phip bio ve.<br /> 294 Tuyln tgp HQI nghj KHOA HQC TOAN QUOC V£ SINH HQC BI^N VA P H A T T R | £ N SfeN V O N G<br /> <br /> <br /> <br /> 3. Pham Ngpc Dang, Truong Vii Hai. Ngudn lgi tdm biln Vift Nam; Bao cao khoa hpc; Vifn<br /> nghifn cim Hai san.<br /> 4. Vii Vift Ha va ctv (2003). Bao cao tong kit dy an ALMRV giai do^n 2.<br /> 5. Vifn nghien cuu Hai sin. Tinh hinh phan bd bai tdm frong nam 1975<br /> 6. Sparre, P. and S. C. Venema (1998). Infroduction to fropical fish stock assessment. Part 1.<br /> Manual, FAO Fisheries Technical Paper. No. 306/1, Rev. 2. Rome, FAO. 407p. ISBN 92-5-<br /> 103996-8<br /> <br /> <br /> <br /> SHRIMP RESOURCES IN THE WESTERN OF TONKIN GULF<br /> <br /> Mai Cong Nhuan, Doan Van Du, Nguyen Cong Con<br /> <br /> SUMMARY<br /> <br /> In the period from 2002 - 2003, there was 4 shrimp surveys with 159 bottom frawl hauls<br /> conducted in the coastal zone of the Tonkin Gulf. The results showed that a total of 36 shrimp<br /> species belonging to 15 genera and 6 families was identified. Penaeidae family was the most<br /> abundant in term of number of species and contributed a high ratio in total shrimp catch. Results<br /> also indicated that Shrimp resources were sharply fluctuated, from 1.700 to 4000 tons. Catch per<br /> unit of effort of shrimps was relatively low, especially for tiger shrimp, Japanese king prawn,<br /> Slipper lobster.<br />