KHOA HOC C O N G N G H |
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a VIJNG BIEI\I THANH HDA V A LAN C A N
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S6 U^u tiling d, c6 con thu 1h^ trong giai doan 2003-2013 dupc su dung di phSn tich, xac dinh khu vi,rc sinh sin vd Idiu vyc uong nudi tu nhi^n ctia mOt s6 loai ck biin b vimg bi^n Thanh H6a vk lan c ^ . K^t qua nghien cuu cho thity, khu v^tc pban h6 tap trung cua trtfog c i chfl y^u a cua Lach Sung den Lach Ghep vk khu vyc ven bi^n k ^ dai tii cua sdng Yen Hoa, Nghi Son CThanh Hoa) &ia caa L^ch Quen, Quynh Luu (Ngh§ An). C& con phan b6 chii y^u o vimg ven bi^n Lach Sung - Hdn N? va I^ich Hdi d&i Lach Ghep. Tdng hgp tbdng tin tit phan b6 tning ca, ca con vi cau tnic t ^ suiit c h i ^ dai cua ca tii viing bien ven bd ra vung khoi, da xac dinh dugc c ^ khu vuc sinh san vi uong nudi tu nhidn cua ci nuc so vi ci mdi Ii: 1) Khu vuc sinh sin bao gdm toan bd viing bdr gidi han v^ phia bic li ciia sdng Diy va pbia nam li mui Bang h u y ^ Tmh Gia; 2) khu vuc uong nudi tu nhidn chu y^u li cic vimg tii ciia sdng Day d&i bai bi^n Hoing Trudng, trung tim li dao Hdn Ne vi phia bdc ciia sdng Mi k^o dii d^n mOi Hai Ninh huyen Tmh Gia Nhung thdng tin niy gdp phin cung cip co sd khoa hpc cho vi§c xac dinh khu vuc bao v§ ngudn gidng thiiy san d vung bi&i Thanh Hda vi lin cin vi muc ti^u duy tri ngudn lpi bdn vQng.
Tb Idida: Giaido^sdm, tningci, cicon, vdng sinh sin, vdng mmg nudity nhidn.
1. Mik Biiu
Vimg bi&i Thanh Hoa nam 6 phia tSy vinh Bac bo IA m^t trong nhung khu vue eo da dang smh hpc cao v i Ii bai de cfia n h i ^ loii hai dac sSn. Trong nhimg nam gdn day, trudc dp Iuc khai tiiic a vinh B ^ bo ndi chtmg v<i b vimg bi^n Thanh Hda ndi rieng tang Ito, nfen nguon lgi hai san trong khu vuc bi suy g i ^ , nhOng doi tupng cd gia tri kinh t^ cao dang bj khai thie q u i mtic, chat Iugng ngudn lgi ngay cing suy g i ^ . Bao v§, tai t?io v i phat trien ngudn lpi trd len c ^ tiiiet vi muc tieu duy h i b ^ vQng ngudn lgi.
HiOn nay, q u ^ 1^ ngh^ ck txtn tii^ gidi dugc thuc hi$n biing nhidu ti^p c|ui khac nhau nhm thinh I ^ cic khu bao tdn biln, cic khu hao vh ngudn gidng tiiiiy san, c ^ khu vuc han che khai tiiic va khai tiiie theo h ^ nggch Oennmgs et al., 2001). M6i ti^p c$n quan \f nghd e i dua tr6n nhirng ndn tang khoa hge cy Ihi v i dugc ap dung khac nhau vdi tung khu vi;tc ti^n till gidi. Quan \f nghd ca dua vao han nggch tiiudng dupc i p dung b e i c nudc 6n ddi. Ddi vdi cie nudc niim trong vung nhi§t ddi cd da dang sinh hpc cao, thinh phdn loii da dang thi vi§c i p dyng phuong p h ^ quin \f nghd e i dua vio hgn
' Chi cvc Khai diic vi Bio v? ngudn Igi Thiiy san Thanh Hda
' Vi^ Nghien cihi Hii sin
nggch khong thd thuc hi§n. Tidp c ^ phii hpp dd quan \f nghd c i a cic nudc nhidt ddi Ii xiy dyng cic khu bao tdn biln, c i c khu vuc bao vd ngudn gidng tiiuy san (UNEP, 2007) hoic eic khu vyc hgn chd khai thic theo thdi gian.
Co so khoa hge cho v i ^ xac dinh khu vyc b i o vd ngudn gidng tfiuy s i n l i c i e nghidn cuu vd giai dogn phit tridn sdm cuia cie loii thuy sin nhu nghidn Clhl vd tnmg ci, c i con, khu vue smh sin v i khu vyc uong nudi ciia chung. Nhiing nghidn a i u niy c6 f nghia d i e bidt quan trgng v i I i ca sd khoa hge cho vide quin \f ngudn Igi sinh vgt bidn ndi chung v i nguon ipi c i hidn ndi ridng. Nim dupc thinh phin khu he, khu vue sinh sin, khu vue uong nudi tu nhidn ciia cic loii sinh vit giiip eie n h i quan 1^, cic n h i hogch djnh chmh sich dua ra nhiing ehidn lugc khai thie hidu qui, ddng Ihdi bao vd ngudn Igi theo hudng bdn viing.
Trong nhiing nim gin diy, nhting nghidn euu xic dinh khu vuc sinh sin, khu vye uong nudi tu nhidn eua cic loii ca hidn d i dugc thyc hidn timg ddi tugng cu thd. 6 khu vuc Bic Au, vimg smh sin ciia nhidu loii c i bidn da dugc xic dinh: c i tuydt (Gadus morbua) (Vitale et al., 2008; Bdnesson et al., 2013), c i hon (Pleuronectes platessa) QlufiiagI et al., 2013) vi mOt sd loii c i khic (Cook et al., 2011; Casaretto et al., 2013; Gundersen et al., 2013). 6 ehiu A, Trung Qudc v i Nhit Bin l i nhQng nudc cd nhidu nghidn cQu ehuydn siu vd giai dogn sdm eua cic loii e i
N 6 N G NGHI?P V A PHAT TRI^N N 6 N G T H 6 N - KV 1 - THANG 8/2014 101
bidn. Trong nhiing nam g i n diy, khu vwc smh san cua nhidu loii c i bidn b khu vyc ven bien trii dai tu Nhat Ban den Nam Trung Qudc diroc xac dinh (Yamada et al., 1998; Dou et aL, 2007; Wang & Xia, 2009; Iwata et al., 2010; U et aL, 2014). Nhiing nghidn euu ve SIX phit tan eiia trung c i sau miia sinh s i n dudi tac ddng cua dong chay va gid eung dupc thuc hien (Li et al., 2014). Tren ca sd phan bo ciia tning ea, e i con OfGCC) trong va sau mua sinh san, cac khu vuc b i o vd ngudn gidng thuy sin da dugc xic dinh, tur do mdi qudc gia ddu cd bidn p h ^ bao vd phu hgp nhim duy tri ngudn loi v i dam b i o khai t h i e ben viing.
O vimg bien vinh Bac bd, nhidu nghien euu xae dinh bai de ciia eae loii hai san noi chung va rieng cho cac nhdm tdm, c i ndi rieng da dupc thuc hidn tuang ddi nhieu nhung voi pham vi nghien cuu kha rpng. Mdt sd tie gia eung nhu cdng trinh nghidn cuu cd the duoc ke den bao gom edng trinh cua Nguydn Hihi Phung (1994), D5 Van Nguydn (1977), Dd Van Nguydn (2000), Dd Van Nguyen v i nnk (2006), Phgm Quoc Huy v i nnk (2008) va Pham Qude Huy
Bang 1. Ngudn
v i nnk (2012). Kdt qua cua cic cdng tiinh da xic dinh dugc b i i de ciia c i c loii e i ndi chung d vung bien nghidn a h i . 6 vinh B i c bd, bai de tiiudng bao phu mdt vung hidn rdng ldn tir ven bd Cit Bi-Long Chau qua ciia Ba Lat ddn phia b ^ hdn Me, ven bd tir hdn Me ddn hdn Mit, ven bd tii hon M i t ddn hon Son Duong v i phia nam hon Gid (Pham Qu6c Huy vi nnk, 2012).
Ttr ngudn sd lidu dieu tra tning c i , ea con do Vidn Nghidn euu Hii sin tiiu tiiip trong giai doan 2003- 2013, chung tdi tidn hinh phan tich, xac dinh die didm phin bd cua tning ca, c i con trong Idiu' vyc bidn Thanh Hda v i lin cin, ttr dd dd xuit cic khu vue bao vd ngudn gidng thuy sin lim ea sd cho vide quin 1^
nghe c i v i b i o vd ngudn Ipi hai sin cua dia phirong.
2.TJU1CU VA PHUONG PHAP NGM&U CUU 2.1. Tii hdu nghidn cihi
Tii heu su dyng trong nghidn ciiu dugc tip hpp tir nhidu ngudn khic nhau thudc cic de t i i / d y i n do Vidn Nghidn ciiu Hii sin thyc hidn trong giai doan 2003-2013 ( B i n g l ) .
sd lidu siJr dung
STT Dd t i i / D u an Thdi gian thirc hidn
Nghidn eiiu tru lupng v i kha nang khai thae cac Ioai ca ndi nho chii ydu l i c i nyc, ca trich, c i bgc m i d bidn Vidt Nam
2003-2005 Danh gii hidn trang va dd xuat cae hien phap bao vd tning e i c i eon v i i u
tning tdm tdm con d vimg bien ven bd vjnh Bac bd
2011-2012 Nang cao nang lue bao vd tning c i , ea eon v i ^u trimg tdm, tdm eon tai
viing ven bidn va eua sdng tinh Thanh Hda
2010-2012 Dieu tra tong the hidn trang da dgng v i bidn ddng ngudn Ipi h i i sin hidn
Yidt Nam
2011-2013 2.2. Phgm vi v i ddi tugog nghien cQu
Pham vi nghien ciiu Ii vung bien Thanh Hda v i lin can. Phia ddng gidi ban ttr tuyen long trd vio.
Gidi han ve phia Bac l i vi tuyen 20"00N va phia Nam Ii vi hiyen 19°00N (Hmh 1).
Ddi tuang nghien ciiu Ii tnmg c i v i c i con thude hg c i khe v i hp ea mdi. Ngoai ra, chiing toi tien hanh phin tich e^u tnic tin suit chidu dii cua cic loii c i nuc so {Decapterus maruadsi) dai dien cho hp ea khd v i c i mdi ttiudng {Saurida tumbil) dai didn cho hp c i mdi theo khdng gian, tir viing bd ddn vimg ldng va vimg khoi Iam bang chiing cho cic nhin dinh vd su phit tan eua c i con v i c i trudng thinh sau mua sinh sin.
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Utn d m trong giai doan 2003-2013 102 NONG NGHIEP VA PHAT TRIEN NdNG THON - Kt 1 - THANG 8/2014
KHOA HOC C O N G NGHl
23. Phuong p h ^ tfau tii^ sd U^u
Miu TCCC dupc thu thap Ifaeo htrdng din cua Gunderson (1993). Thidt bi thu miu la ludi thu miu sinh vit phu du dugc ciu tgo hang spi ni long, ldch thudc mat ludi 450 pm gdm: 1) ludi keo tang mat va ting diy cd midng hmh chii nhit, chidu dii 1 m, chidu rpng 0,5 m ra 2) ludi keo ting thing diing ed midng hinh trdn, dudng kinh 0,8 m.
Tgi tram nghien ciiu, sau khi tau di dung ban khoang 15 phiit tin tidn hinh thu mlu TCCC d ting thing diing. Miu TCCC d ting m|Lt va tang diy thu vdi tde do chay tau khoang 2 hai ly/gid trong thdi gian khoang 5-10 phiit
Ludi keo ting mat dugc thi cich man tiu
khoang 30 m vi ed dinh vio mgn tiu. Khi thu miu, cho tiu ehay theo hudng ngugc sdng, vdi tdc dp khoing 2 hai ly/gid. Thdi gian kdo ludi khoang 5-10 phiit tinh tir khi ludi diu dn dinh eho tdi Idii ludi bit diu dugc kdo Idn.
Ludi kdo thing dung. Khi thu miu Iirdi dugc tbi
theo phirong thing diing, sao cho midng ludi vda chgm diy. Ludi dugc kdo Idn vdi tdc dd vira phii dim bao qui trinh thu miu khdng hi hidu ung trin.
Ludi kdo ting diy dugc thi d phia sau tiu, chidu
dii diy thi tuy thugc vio dg siu nai lhu miu. Khi thu miu, cho tiu chay theo hudng ngupc sdng vdi tdc dO khoing 2 hii \f/ gid. Thdi gian kdo ludi 5-10 phiiL
Lugng nudc qua ludi dugc xie dinh bang thidt bi do lugng nudc qua ludi gin d midng ludi. Miu dugc riia sgch bio quin trong Ig nhya cd dung tich 1 lit, cd djnh miu bing fomandehyt 5%.
Mau TCCC dupc phin tich bing kinh giii phau Nikon SWZIOOO, KRUSS vi kmh hien vi Nikon E200.
TCCC dugc nh$t ra khdi cic sinh vat phii du vi ric bin khic, ehti vao dng nghidm nut bing bdng tham nudc vi luu giu trong binh ed chiia fomandehyt 5%.
TCCC dupc phin Ioai dya vio eie tii lidu eua Nguyin Hiru Phung (1973. 1976, 1978, 1980, 1991, 1994), MSto (1960,1961).
2.4. Phuong ^h&p phin tieh sd lidu Viing sinh sin vi vimg uong nudi tu nhidn dia ei d vimg bidn Thanh Hda vi lin can dupc xic dinh dya h-dn mit dd phin bd eiia TCCC trong vimg biln nghidn ciiu dya trdn sd lidu tiung bmh nhieu nim tii eie chuydn didu tia giai dogn 2003-2013.
Mit do TCCC (D) dupc xic dinh trdn ea sd sd lupng TCCC (N) vi lupng nudc qua ludi theo cdng
tinic D=N/V*100Q. don vi Ii tiung ho$c ci ttil/1000 m^ nudc. Lugng nudc qua ludi dugc dnqrln ddi tir sd vdng quay eua thidt bi do luu lupng nudc qua ludi
fflowmete-) theo rang thiic:
V = 5 • r - [ ^ ) • 0.2324 + 0,0497]
Trong dd: V ii Iugng nudc qua ludi (m^; S Ii didn tich midng ludi (m^; T li thdi gian keo ludi
^iiy) va X li sd vdng quay trdn thilt hi do lupng nudc qua ludi.
Phin bd cua TCCC dugc hilu didn bang gii hi mit dp phan bd tnmg binh nhidu nam ciia timg nhdm trong d bidn nghidn ciiu. Bin dd phin bd dupc xiy dung hang phuong phip ngi suy tii cic dilm Ian can vi dupc thi hidn bang duong ddng miic.
Viec xic dinh khu vuc bao vd ngudn gidng thuy sin dupc ihuc hidn dua trdn mit dd phin bd ciia TCCC vi phin bd kich thude ei till ciia cic loii dgi didn trong vimg bien nghidn eiiu. TVdn ca sd phin tich mgt do phin bd tning ei, ei eon, khu vyc bai de vi bai uong nudi tu nhidn ctia eic nhdm ngudn Ipi se dupc xic dinh. Khu vue bao vd ngudn Ipi dugc phin chia thinh cic vimg khic nhau, gdm vimg ldi vi vung ddm. Trong nghidn cuu niy, vimg Idi dupe xic dinh li khu vyc cd mit dO phan bd cua tning ci, ci con cao hon mit dd phin bd trung binh tii 90% trd Idn. Vimg ddm li khu vuc cd mit dO phin bd cao han mit do tiung binh tii 75% ddn 90%.
8. Kir qui MSlAl GUI VA THAO LU^
3.1. Phin bd tning c i trong m ^ sinh sin Kit qua phin tich tdng hpp dii hdu tning c i thu thgp d viing biln Thanh Hda v i lin cin trong giai dogn 2003-2013 cho tiiay, hai khu vyc cd mit dO phin bd rat eao eiia tning c i li: 1) ciia Lgch Sung din Lgch Ghep v i 2) khu vuc ven biln kdo dii tii ciia sdng Ydn Hda, Nghi Son (Thanh Hda) din ciia Lgch Quen, Quynh Luu (Nghd An). 6 cic khu vyc niy, mgt dg phan bo tnmg binh dat miic trdn 5000 tning ci/1000 m^ nudc. Khu vyc xung quanh Hdn Ng l i noi cd mat dg phin bd cua tning c i cao n h i t Tir ven bd ra viing lgng v i vimg biln khoi, mit dp phin bd ciia tning c i giim dan. Cic khu vyc cd mgt dp phin bd tiTing c i d miic 3000-5000 tining ci/1000 m^ nudc tip tnmg d phia ddng bic dio Hdn N? tiiuOe khu vye cua sdng Diy v i eua sdng Ninh Co nim trong viing Ipng eua tinh Nmh Binh v i khu vuc tii Hdn Md ddn cang Nghi Son. Cie khu vyc khic d viing bd viing
N 6 N G NGHIDP V A PHAT TRIIN NdNG THdN - KY 1 - THANG 8/2014 103
khoi biln Thanh Hoa, mat dd phan bd ciia tning ci thip, chii ydu trong Idioing dudi 2000 tning ea/1000
Hinh 2. Phin bd tning ci (tning ca/1000 m^ d vimg biln Thanh Hda vi phu cgn dua trdn sd lidu trung
hmh nhilu nim giai doan 2003^2013.
3.2. PhSn bd ctia ci con
Suphan bd cua cicon ddi vdi tin iQ khie nhau CO su khic bidt nhat dinh. Ci con hg ca khd phan bd vdi mat dd rit cao chii ydu nam trong dii dp siu dinSl 20 m nudc d hai khu vue chinh li (1) vimg ven bien Lach Sung - Hdn Ne vi (2) vimg ven bien Lach Hdi din Lach Ghep. O khu vuc nay, mat dp phan bo d eon cua hg ea khd nam trong khoang 500-860 ci the/1000 m^ nudc (Hmh 3). Cac khu vuc khac trong vimg biln Thanh Hda vi lin cin ed mit dd phin bo cua ci con hg ca khd chu ydu nam trong khoang dudi 100 ci tiie/1000 m^ nudc.
Phin bd cua ca con hg ci mdi sau mua sinh san tip trung han so vdi phin bd eua ea eon hp ea khd.
Ket qua phin tieh eho thiy, khu vuc phin bd vdi mat dd rat eao ehu yeu tap trung d khu vuc ven blln Lach Hdi, trong phgm vi 3 hai ly trd vio bd. Mat do phin bd cao nhat d khu vue nay dat 769 ci thl/1000 m^
nudc (Hinh 3). Cac khu vuc ed mit dO phin hd kha cao tap tnmg thinh 3 vimg chinh, gom (1) cua Lgch Sung - Hdn Ne; (2) eua Lach Hdi den Lgch Ghep tiii rdng den tuyen long vi (3) vimg khoi giap vdi tuydn long cd tam tpa dp Ii 19° 30' 32" N vi 106° 42' 13" E vi cd bin kinh 2,8 hai ly (Hinh 3).
Hmh 3. Phin bd mit dO ei eon (ci tiid/1000 m^ nudc) hp ci khd d bdn tiii vi hp ci mdi d bdn phii d viing bidn Tiianh Hda vi phu can dua ti'dn sd lidu tnmg hmh nhilu nam giai dogn 2003-2013.
3.3. Xic dinh khu vuc bio vd ngudn Ipi Ket qua tong hop cic dir lieu mat dp phin bo ciia tning ca thu thip dupc tii eie hoat dpng dieu tra, nghien cuu trong giai doan 2003-2013 d vung biln Thanh Hoa va lan can cho thay, vung sinh san cua cac loai ca tip trung chu yeu d viing nudc ven bd
ti-ong pham vi dai dp sau 20 m nudc (Hmh 4). Tidn hinh loai bo cie khu vuc cd mit dp phin bd thap hon so vdi gii tri mat do phin bd tiung binh, khu vyc phin bo tap trung cua tning ci cao hon gii tii himg binh 90% dugc xie dinh Ii vung biln ven bd keo dai tir cua sdng Day den Lach Quen (Ngh> An). Khu vuc
104 NONG NGHIEP VA PHAT TRIEN NONG T H 6 N - KY 1 - THANG 8/2014
KHOA HOC C O N G NGHfi
cd mat do phin bd cao hon g i i tri mit do tnmg binh 75% tap trung d 3 khu vyc ehinh li: 1) Vimg tilp g i ^ vdi khu vyc mit dO phin bd rat cao, 2) khu vuc ngoii khoi cua diy tilp giip vdi dudng ranh gidi tuydn hd - tiiydn ldng v i 3) khu vuc ngoii khoi vung biln Thanh Hda, nim tilp giip vdi duong ranh gidi tuyln ldng - tuyln khai (Hmh 4).
Ci con phin bd tip bung d 5 tiiu vimg nho (Hmh 4), gdm: (1) Vimg cua Lgch Sung - Hdn N^;
(2) vimg cua Lach Hdi den Lgch Ghep; (3) vimg tilp giip tuyen long cd tga dp trung tim Ii 19° 29' 8" N, 106° 29* 13" E va cd bin kinh 5,2 hii ly; (4) vimg tidp g i ^ vdi tuyln bd cd tga do tnmg tim li 19° 30" 22"
N, 106° 8' 51" E v i cd chieu dii 5,6 hai ly, chidu rdng 2,6 hai Iy; (5) vimg cua Lach Quen (Nghd An).
Hmh 4. Khu vuc phin bd tip trung cua tning c i (bdn trii) v i c i con O^dn phii) b biln Thanh Hda v i lin cin Ket qua phan tich tan suat chieu dai ciia cac loai lpi nam 2012-2013 cho thay, cau tnic tin suat chieu ci nuc so va ca moi thudng b viing bien TTianh Hoa dai ciia cac loai co su khac biet rat Idn giua vimg bd.
vi Ian can thu thap trong cac chuydn dieu tra nguon viing long va viing khoi.
Hinh 5. Phin bd tuin suit chidu dii c i nyc sd d biln TTianh Hda v i phu cin dua trdn kdt qui didu tra ngudn lpi nam 2012,2013 ciia du in didu tra tdng thi hidn trang vi bidn dpng ngudn Ipi hii sin biln Vidt Nam
Ddi vdi loii c i nuc so. phin bd d viing bd chu ydu la con non cd kich thudc nhd ban chidu dii lin diu tham gia sinh san chidm 74,0% tdng sd ca the ciia din ci. Kich thudc Idn nhat cua c i nuc so bit gap d vung bd Ii 14 cm (Hinh 5). O vung Ipng, da bit gap cic c i thi cd kich thudc ldn hon hon chieu dai lan
dau tham gia sinh san nhung nhom nay chi chilm ti le 1,9% tdng sd c i the. Trong vung long, nhdm chidu dai uu thi tuong tu nhu vung bd, chu ylu thupc cic nhdm 10 - 13 cm chiem 77,1% ve sd lupng.
O viing khoi, cau tnic dan ca nuc di cd su dich chuyin rd rang hon ve thanh phan cic nhdm chidu
NONG NGHIEP VA PHAT TRIEN NONG THON - KY 1 - THANG 8/2014 105
dii so vdi vimg bd v i vimg long. Ca thd ed Mch thirdc ldn hon chidu dai Ian diu tham gia sinh san chilm ti le 9,4% ve sd luong (Hmh 5).
Ddi vdi loii ea mdi thudng, eau tnic din ca trong vimg bidn Thanh Hda va Ian can tuong ddi da dang, kieh thudc e i the dao ddng 7-31 cm. Phin bo cau tnic chieu dai cua dan ca cd dang hinh chudng up va ed su dan xen chat che cua cac nhdm khac nhau. Su dieh chuyin cua cau tnic kich thudc din c i theo vimg bd, vimg long va vimg Idiai vdi tim la chilu dai thinh ihuc lan diu dupc the hidn k h i rd. Nhdm
chieu dii uu thd trpng tim d vimg bd la 16 em va nho hon so vdi nhom chieu dii trpng tam 18 em cua cic viing khic. O vimg bd, ty Ie din ca con non ehua thinh thuc va dan ca bd me la 77,3%: 22,7%, ti'ong khi dd d vung long la 43,7%: 56,3% va vung khoi l i 31,8%:
68,2%. Nhu vay, din ca eon non kich thirdc nhd cd xu hudng tip trung d vimg nudc ndng ven bd va din ci bd me cd kich thude Idn tap trung d eac vimg nudc siu hon dupc thd hidn ro. Ddng tiidi, cac d i n ca nhd ed xu hirdng dich chuyin dan ra viing biln khoi trong q u i trinh sinh trudng phat tridn.
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I J L .Hmh 6. Phin bd tuin suit chilu dii c i mdi thudng d biln Thanh Hda v i phy cgn dua trdn k i t qua didu tra ngudn lpi n i m 2012,2013 cua du i n didu tra tdng thd hidn trgng v i biln ddng ngudn Igi h i i s i n biln Vidt Nam
Ket hgp giira ban dd phan bd cic khu vuc tap trung cua tning ca va c i con d vimg bien Thanh Hda v i lin ein cho tiiay, vimg bidn ven bd gioi han tir 20 m nudc trd vio tii cua sdng Day ddn cang Nghi Son la khu vuc phan bd chinh cua tning ca va ca con.
Trong do cic khu vuc ven bd Lach Sung - Hdn Ne va Lach Hdi - Lach Ghep la nhiing khu vyc cd mat dd phin hd ca con cao hon so vdi cac khu vuc khic. Cac khu vuc nay ed the xem xet dd xuit xay dung khu vuc bao ve nguon gidng thuy sin d Thanh Hda.
Kit qua phan tich tdng hop phin hd cua tning ci, ca con v i cau tnic din e i d eac vung bd, vung long va vimg khoi trong viing biln Thanh Hda eiing nhu vide xac dinh cac khu vuc sinh sin, khu vuc uong nudi tu nhidn cua cac loai c i biln la ca sd khoa hoc cho vide khoanh vung bao ve nguon gidng tiiiiy san, gdp phan bao vd nguon gidng ca biln nham phuc hdi vi tai tao ngudn Im ben vung.
4 . KFT LUAN
Trdn eo sd phan tich tdng hgp phan bd eua tning ci, c i con va can tnic din c i d cie vimg bd, Idng, khoi d vimg hiln Thanh Hda vi lin can, sau diy da xie dinh dupc eac khu vuc sinh san va uong nudi tu nhidn cua ca nuc sd v i e i mdi.
Khu vuc suih san bao gdm toin bd vimg bd gidi han ve phia bac la ciia sdng Day va phia nam Ii miii Bang huydn TTnh Gia.
Khu vuc uong nudi ty nhidn chu ydu la cic \ung tii cua sdng Diy den bai biln Hoang Trudng, trung tim la dao Hon Ne va phia bac cua sdng Ma keo dii d i n mui Hai Ninh huyen Tmh Gia.
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SPAWNING AND NURSERY GROUNDS OF FISHES IN THANH HOA PROVINCE AND ADJUNCTION WATERS
Le Duc Giang, Vu Viet Ha and Tran Van Cuong Summary
Iclithyopiaiiitton data collected in penod 2003-2013 were used to determine spawning areas and nursery grounds of fishes in Thanh Hoa provice and adjunction waters. Results indicated that the distnbution of fish egg is dense from Ihe Lacli Sung to Lach Ghep and fi-om Yen Hoa estuary of Nghi Son distnct (Ihanh Hoa province) to L.ach Quen of Quynli Luu district (Nghe An province). Fish larvea is distributed densely trom Lach Sung to Hon Ne and fi-om Lach Hoi to Lach Ghep regions. Evidence of synthetic analysis of fish egg, fish larvea and length fi-equency distribution of fishes fi-om msiiore to the offshore regions revealed that the spawning areas of Japanese scad and Lizard fish are covered the coastal waters from the northernmost of Day estuary to southernmost of Bang cape of Tinh Gia district The nursery grounds of these species are concentrated from Day estuary to Hoang Truong beach with the cenUe is Hon Ne island and the region fi-om the northernmost of Ma estuary spreading to Hai Nmh cape of Tmh Gia district Tills results support basic mformafion for determining the fisheries refiigia in Thanh Hoa province and adjunction waters with objectives of maitaining the fisheries resources sustainably.
Keywords.-i?ar/rif/e stages, egg, larvea, spawning ground, nursery ground.
Ngudi phan bien: TS. Chu Tiln Vinh Ngay n h t o bai: 20/6/2014 Ngay thdng qua phan bi$n: 21/7/2014 Ngay duydt dang: 28/7/2014
108 NONG NGHIEP VA PHAT TRIEN N 6 N G THON - KY 1 - THA 9/2014
