HQl NGHj KHOA HQC T O A N Q U O C Vg SINH THAI VA T A I N G U Y E N SINH VAT L A N THLf 5
HIEN TRANG HE SINH THAI RlTNG NGAP MAN VA THAM CO BIEN Cf KHU VlTC DAM THUY TRIEU
TINH KHANH HOA
NGUYEN XUAN HOA, NGUYEN THI THANH THUY, NGUYEN NHAT NHU" THUY Vign Hdi duang hgc.
Viin Hdn ldm Khoa hgc va Cong ngh^ Vift Nam Dam Thuy Trieu thudc huyen Cam Ldm, tinh Khanh Hda cd dien tich khodng 2.000ha von Id noi cd he sinh thdi rilrng ngap man vd thdm cd bien rat da d^ng vd phong phu. Tuy nhien, nhirng nam gan ddy dudi siic ep cua su gia tdng ddn sd va phdt trien kinh te- xa hpi nhanh chong lai dja phucmg, nhieu dien tich rimg ngap man vd thdm cd bien da b) bien mat ho^c suy thoai (Nguyen Xuan Hda, 2009, 2010). Bai bao neu len hien trang he sinh thai rirng ngap man, Iham CO bien vd ngudn Igi thiiy san lien quan Irong dam Thuy Trieu nham cung cdp cg sd khoa hpc cho viec thiel lap ca che quan ly va sir dung ngudn Igi trong dam mpt each ben viJng.
I. TA! LIEU VA PHU'OfNG PHAP NGHIEN CUtJ
Bai bdo su dung ngudn lu lieu sdn cd ciia chinh nhdm tac gia (Nguyen Xuan Hoa, 2009;
2010) ket hpp vdi cac kel qua dieu tra, khdo sat bd sung vao thang 7- 8/2012.
Khdo sat sir phdn bd va cau true ciia riing ngap man, thdm cd bien trong dam Thiiy Trieu dupe lien hanh dua theo cac tdi li?u "Sach hudng dan dieu tra ngudn Ipi bien nhi^t ddi" (English et ai, 1994) va "Sd tay hudng ddn giam sat va dieu tra da dang sinh hpc" (WWF Chuong trinh Ddng Ducmg, 2003).
Ket hgp vdi ban dd vien tham, tai mdi dia didm khao sdt riing ngdp m|n, xac djnh tpa dp va lap cac tuyen khao sat dpc theo dudng bd. CJ nhung noi rimg ngdp m|n cd b^ ngang rpng, i?p them cdc tuyen khdo sat thang gdc vdi dudng bd. Tren cac tuyln khdo sat ghi chep thanh phan lodi va nhCrng nhdn xet ve hien trang, ddc diem phan bd ciia riing ngdp m|n.
Khdo sdt cdc thdm cd bien dugc thuc hien tren dien rdng trong dam va k6t hgp phdn tich anh vien thdm. Tai cdc dilm khdo sat tien hdnh xdc djnh tpa dp, thill lap mat cdt khdo sat tir viJng trieu den do sdu phdn bd ciia thdm cd bien. Xdc djnh thanh phdn lodi vd ddnh gid dp phii cd bien dpc theo tuyen mat cdt. Su dung khung vudng cd dien tich 0,25m' de thu mau xac djnh mat dp, sinh lugng ciia cd bien. Mat dp cd bien la sd lugng than diing trung binh cua cd hien trong khung dugc quy ra don vj 1 m" (cay/m^). Sinh lugng cd bidn Id trpng lugng trung binh ciia cd bien trong khung dugc quy ra dem vj 1 m" (g.khd/m^) sau khi dugc riia s^ch, sdy khd d nhiet dp 60°C trong 24 gid va can d phdng thi nghiem.
Djnh Ioai cay ngap man dua theo cac tai lieu cda Vien Ngpc Nam va Nguyen Son Thyy (1999), Shozo el al. (1998). Dinh loai cd biln dua theo tai ll?u cua Philips vd Menez (1988);
Fortes(l993).
Thiet lap so do phdn bd va tinh dien tich rirng ngdp man, tham cd bien dya tren kit qud dieu tra thuc dja ket hgp phan tich anh vien thdm va phan mem Maplnfo.
HOI NSHI KHOA HQC T O A N Q U O C Vt SINH THAI VA TAl NGUYEN SINH VAT L A N THLf 5 a KET QUA NGHIEN CtTU
1. Hien lr«n8 "•mg ngap m?n 6- Sam Thuy Trilu l.l. Thinh phan loai cay ngap man
Thanh phkn loai cay ngap man trong dam kha ngheo voi 26 loai dugc xac dinh, frong do CO 16 loai cay ngap man th^t sir (true mangroves) va 10 loai cay tham gia rirng ngap man (mangrove associates) (bang 1).
Bring I Thanh phan Ioai cSy ng^p man tf dam Thiiy Trieu
TT Ten khoa hpc Ten Vi^t Nam
Cdc loai ng|p man chiJ y§u (true mangroves) Hp Rau d i n g (AIZOACEAE)
1 Sesuvium portulacastrum L. Sam biln Hp Mim (AVICENNIACEAE)
2 3 4
Avicennia alba Blume Avicennia marina fForsk.) Vierh Avicennia officinalis L.
Mam trang Mam bien Mdm den Hp Dan nem (MYRSINACEAE)
5 Aegiceras corniculatum (L.) Blanco Sii Hp Cau dfra (PALMAE)
6 Wypa fruticans Wurmb Dira nuoc
Hp Rdng (PTERIDACEAE) 7 Acrostichum aureum L.
Hp Bang (COMBRETACEAE) 8
9
Lumnitzera littorea (Jack) Voigl Lumnitzera racemosa Willd.
Rdng dgi
Cdc do Coc trdng (Coc vang) Hp Dude (RHIZOPHORACEAE)
10 11 12 13 14
Bruguiera cylindrica Blume Bruguiera gymnorrhiza (L.) Lam.
Rhizophora apiculata Bl.
Rhizophora mucronata Poir. In Lamk Ceriops decandra (Griff.) Hp Thau ddu (EUPHORBIACEAE)
15 1 Excoecaria agallocha L.
Hp Bdn (SONNERATIACEAE) 16 j Sonneratia alba J. Sm.
Vet trg Vetdu Dude. Dude dot Bung, Duoc bop Da quanh
Gia
B^n Irang
HQI NGHI KHOA HQC T O A N Q U O C V S SINH THAI VA TAI NGUYEN SINH VAT LAN THp' 5
TT Ten khoa hpc Ten Vi?t Nam
Nhu-ng lodi tham gia rCrng ng^p m^n (associate mangroves) Hp Thien ly (ASCLEPIADACEAE)
17 Gymnanthera nitida Hp Cue (COMPOSITAE)
18 Pluchea indica (L.) Leres Hp Bong (MALVACEAE)
19 20
Thespesia populnea (L) Sd ex.Corrs Hibiscus tiliaceus L.
Loa hCing, ddy mu
Cue tan, Luc
Tra lam v6 Tra nhdt Hp Dau (FABACEAE)
21 Derris trifoliata Lour Coc ken
Hp Bim bim (CONVOVULACEAE)
22 Ipomoea pes-caprae (L.) Rau muong bien
Hp Sim (MYRTACEAE)
23 tUlelaleuca cajeputi Powell Tram
Hp Cd roi ngy-a (VERBENACEAE) 24 Clerodendron inerme (L.) Gaertn.
Hp Gai me (SALVADORACEAE) 25 1 Azima sarmenlosa (Bl.) Benlh. & Hook.
Ngpc nu, Chi!im gpng
Chilim le Hp Dira d|ii (PANDANACEAE)
26 Pandanus tectorius L. Dua dgi
Cdc lodi cay ngap man phd biln d ddm Thiiy Trieu Id Duoc {Rhizophora apiculata), Dung (Rhizophora mucronata), Mdm trdng {Avicennia alba), Mdm biln {Avicennia marina). GiA (Excoecaria agallocha) vd Cdc trang {Lumnitzera racemosa). Dang chu y Id cd su xuat hi?n cua lodi Cdc dd {Lumnitzera littorea) d dam Thiiy Trieu. Day la loai cay ngap man quy hiem, co ten trong Sdch Dd can dugc bdo tdn d Viet Nam va nhieu qudc gia tren thi gidi.
1.2. Phdn bo cila rirng nggp mgn
Cdc ket qud khdo sat cho thdy rirng ngap man ty nhien trong dam Thuy Trilu hdu nhir khdng cdn, chi cdn lai cac dai cay ngap man nhd hep phdn bd dgc theo dudng bd phia Ddng ciia dam thudc xa Cam Hdi Ddng, hoac phan bd rai rac tren cdc bd ao, dia nudi thuy san d cdc xS Cam Hdi Ddng, Cam Hdi Tay vd Cam Hda. Tdng dien tich cdc ddi rirng ngap man d khu v\rc ddm Thuy Trieu khodng I4ha (Nguyin Xuan Hda, 2009; 2010).
Cac qudn xd cay ngap man dien hinh, thudng gap d ddm Thuy Trilu ia:
- Quan xa Duoc {Rhizophora apiculata)-Bung {Rhizophora mucronata): Rdt phd bien cr viing dinh dam, thupc cdc xa Cam Hda va Cam Hai Ddng, hdu hit la cdc dai rirng trdng bao v?
bd dia.
- Quan xa Dude {Rhizophora aplculata)-Mkm trdng {Avicennia alba)-Man] biln {Avicennia marina): Khd phd biln, thudng phdn bd dpc theo bd Ddng cua dam Thiiy Trilu thudc xa Cam Hdi Ddng.
490
HQl NGHI KHOA HQC T O A N Q U O C V £ SINH THAl VA TAI N G U Y E N SINH VAT LAN THLf 5 - Quan xa Cdc trdng {Lumnitzera racemosa)-Gia {Excoecaria agallocha): Thudng phdn bo rai rac iren nin ddt cao ven dam vd trong viing ao, dia nudi thuy san.
Dang chu y' la tdn tai ddi riing ngdp man tu nhien vdi dien tich khodng Iha phdn bd dpc dudng bd thupc thdn 4, xa Cam Hdi Ddng. Ddi rCmg nay cd thdnh phan lodi kha phong phiJ, nhung pho biln la cdc Ioai Mdm bien. Mam trdng, Dude va Ban trdng. Ddy cQng la noi phdn bd cua 8 cdy Cdc dd ldm cho ddi rirng lu nhien noi day trd nen dac sac can dugc quan tdm bdo ve.
Di?n tich rung ngdp man d ddm Thuy Trieu hien nay da bi suy gidm rdt nhieu so vdi trudc.
Nguyen nhan chinh Idm mat rirng ngdp man Id do linh trang phd rtrng lay dat ldm nha d, khu ddn cu, dudng xd, dac biel Id phong trao pha rung ngap man d at de xay dung cac ao dia nudi tdm.
Hi?n nay, co mdt so ddi cdy Dude hoac Dung dugc trdng phdn tdn dpc theo bd ddm va trong ao, dia bd hoang d viing dinh ddm, thudc xa Cam Hdi Ddng va Cam Hda. Tuy nhien, dien lich rirng trong con rat il di va phan tdn.
2. Hien trang tham cd bien d dam Thuy Trieu 2.1. Thanh phan lodi
Cdc ket qud khao sdt cho thdy thdnh phan loai cd bien trong ddm Thiiy Trieu khd da dang vdi 8 iodi dugc xdc dinh (bang 2).
Bdng 2 Thanh phan loai cd bien d dam Thiiy Trieu
TT Ten khoa hpc Hp Hydrocharitaceae
1 2 3 4 5
Enhalus acoroides (L f.) Royle Halophila beccan/Ascherson.
Halophila minor (Zollinger) den Harlog.
Halophila ovalis fR.Brown) Hooker.
Thalassia hempnchii fEhrenberg) Ascherson.
Hp Cymodoceaceae 6 7 8
Halodule pinifolia (Miki) den Harlog Halodule uninervis (Forskaal) Ascherson.
Ruppia maritima Linnaeus
Ten V i f t Nam
Co la dua Co nan nan Co xoarf nho Co xoan Cd vich, CO bo biln
Co kim bien Co he ba rang Co kim
^ Hai lodi Cd xoan {Halophila ovalis) vd Cd Id dira {Enhalus acoroides) rat pho biln Irong dam Thuy Trilu. Lodi Cd kim {Ruppia maritima) chi ihd^ mpc trong cac ao, dia bd hoang lau ngay. Rieng lodi Cd nan ndn {Halophila beccarii) rdt hiem gap, chi xudt hien trong mua mua khi dp mdn nude ven ddm ha thdp.
2.2. Phdn b6
Cdc thdm cd bien ldn phdn bo chii ylu d Con Giua thudc vimg dinh dam va dgc theo vimg nirdc ndng ven bd ddm thupc cdc xd Cam Hda, Cam Hdi Ddng, Cam Thanh Bdc va Cam NghTa.
Tong di?n tich thdm cd biln trong dam Thuy Trilu khodng 547ha (hinh I).
0 khu vuc dinh dam, ddc biel Id Cdn Giiira loai Cd xoan thudng chiem uu the, lao thdnh cdc tham CO bien ddy cd mat dp vd dp phii cao. Loai Cd la dira c6 kich thudc Idn Ihudng phdn bd d 491
HQI NGHj KHOA HQC T O A N Q U O C V £ SINH THAl VA T A I N G U Y E N SINH VAT LAN THlJ 5 viing nude ndng ven bd phia Nam ddm, noi dp man thudng cao va it dao ddng hon, nhieu noi co Id dira chilm uu thi hodn todn, tao thdnh tham cd don loai. Cac sd lieu do dac ve mat dp, sinh lugng vd dp phu cua cac thdm cd bien quan trpng trong dam Thuy Trieu (nam 2012) dupe Irinh bdy d bdng 3.
Nhin chung, mat dp, sinh lugng va dp phii cua cdc tham cd bien trong ddm ThOy Trieu qua dot khdo sat nam 2012 cd su suy gidm ddng kl so vdi kit qud khao sdt nam 2008 (Nguyen Xuan Hda, 2009,2010).
Hinh I. Sa dd phdn bd cua cdc thdm cd biin a fidm Thuy Trieu
Tham cd biln d Cdn GiiJa thudc vung dinh ddm bj suy thodi nhilu do Rong lyc {Enteromorpha sp., Chaetomorpha sp.j phdt triln manh phii ddy len tren. Hdng chuc hecta co biln d khu vuc ven bd Nhd may Dudng Khanh Hda (xa Cam Thdnh Bdc) da bj suy thi^i nghiem trong, dp phii cd biln chua din 5%, do bj ngucri ddn ddo xdi lien tuc dl khai thae cdc
HOl NGHI KHOA HQC TOAN QUOC V£ SINH THAI V A TAI N G U Y £ N SINH VAT L A N THCf 5 lodi than mim nhu Gid bien. Phi... Cdc thdm cd bien nam dpc ven bd ddm xa Cam Hdi Ddng deu cd sir suy giam ve msit dp, sinh lugng va dg phu so vdi trudc ddy.
Bdng 3 Mat do, sinh Iirgng va do phii ciia mot so tham cd bien trong dam Thuy Trieu TT
1
2
3
4
5
6
7
e
9
10 Dja dilm khao sit
Con giCra- Cam Hai Tay Ven b»- Cam Hai TSy Cam Hoa Cau Hin- Cam Hal Ddng Ciu Hin- Cam Hai Dong
Cam Hai D6ng VOng BCin- Cam Hai Ddng Cam Thanh Bac LSng 6ng- Cam Hai D6ng Cam Hal Dflng
Toa do
12°06'16 4 109°10'06.6
12°06'03.5 109°09'26.1 12°06'50.1 109°09'50.9
12°07'02.6 109°10'21.8 12°06'41.1 109°10'49.8 12°06'21 57 109°10'45.11
12°03'16.03 109°iri5.2 12°03'16 03 109°iri5.2 12°02'37.27 109°ir48.44 12°02'12.2 109°12'05.6
Ten loai H.o H.p H o H.p H.o
H.o
H.o
H.o
E.a
E.a
E.a
E.a
Matdv (cay/m^) 4.522±470 1 082±929 15.525±5.067
1.072±48S 8.938±242
12.117±3.115
5.445±2 692
1.680± 1.612
51±12
27±5
20±7
Sinh lipp'ng [g.kholm') 22.03±5,01 6.97±6.55 87,29*30.63
9.40±4.83 55.88±15,64
73.20±28,62
15,20±12,76
7,5617,47
90,43±15,16
62,71±7,05
60,39123,20 DpphO
32±8
S4±11
77±6
44±33
36±11
10±8
32±11
<'5%
36±11
23±7 Ghichu: H.o; Halophila ovalis, H.p: Halodule pinifolia, E.a: Enhalus acoroides.
3. NguoD Ioi va nguon giong thuy san
Cdc thdm cd biln irong ddm Thiiy Trilu cd dien tich Idn, da dang, mat do, sinh lugng va dp phiJ cao t?o mdi irudng thuan Igi cho nhieu lodi thiiy sinh vat cd gia tri den cu trii va sinh sdn.
Do v|y, cdc tham cd biln da gdp phdn ldm cho ngudn Igi thiiy sdn trong ddm Thiiy Trieu rdt phong phu. Ddy cung Id noi phdn bo ngudn gidng quan trpng cua nhieu loai thiiy san cd gia trj nhu torn, ghe..
Nhirng ddi lugng ngudn Igi cd chi'nh khai thdc dugc trong thdm cd bien vd viing nude Idn c$n trong dam Thiiy Trilu gom: Ca bdng, Cd dia, Cd ddi Id, Ca due, Cd gid, Ca liet, Ca mdm.
Tong sdn lugng khai thdc cdc doi tugng ngudn Igi nay khoang 338 tdn/nam (bdng 4).
HQl NGHI KHOA HQC T O A N Q U O C V E SINH T H A I V A TAI N G U Y E N SINH VAT L A N THCf 5
San lu-gng khai thae ngudn Igi ca chinh trong dam Thiiy Trieu TT
1 2 3 4 5 6 7
Doi t u p n g Ca bong {Acentrogobius sp ) Ca dia {Siganus guttatus) Ca d6i Id {Valamugit cunnesius) Ca dye (Sillago sp) Ca gio {Siganus canaliculatus) Ca liet {Leiognathus sp.) Ca mom (Gerres filamentosus)
Cong cu khai thdc Ld day Luoi ben Lir6\ ben Ludi ben, luoi chi Luoi ben, day Ludi ben Luoi ben
Mua vp khai thdc chinh
Quanh nam 3-12 am l]ch 2-12 dm Ijch Quanh nam 3-12 am ljch Quanh nam Quanh nam Tong cpng (tdn/nam)
San lupng (tdn/nam) 19,80 4,37 77,20 18,35 13,70 6,24 198,78 338,44 Nhirng ddi tugng ngudn Igi thupc nhdm gidp xac khai thdc dugc trong dam Thiiy Trilu gdm cd Cdng Idng, Cua hec, Cua xanh, Ghe, Tdm ddt. Tdng sdn lugng khai thdc nhiing d6i tugng ngudn lgi nay trong dam Thiiy Trieu dat khodng 495 tdn/nam (bang 5).
San lupmg khai thae nguon loi giap xac chinh trong dam Thuy Trieu TT
1 2 3 4 5
D6I tipp-ng Cong long (Uca sp.) Cua hec {Charybdis anisodon) Cua xanh (Scylla serrata) Ghp (Portunus pelagicus) Tom dat {Melapenaeus spp.)
Cong CV khai thae Ludi ghe, Ign Luoi ben, lo ddy, l|n bat tay Ludi b^n. Id day Ludi ghe. Id day Day, soi, Id ddy
Mua v^
khai thdc chinh Quanh ndm Quanh nam Quanh nSm 3-12 am ljch Quanh nSm Tdng cgng (tin/nam)
Sdn lugng (tin/nam) 160.50
69 3,90 188,41
73,15 494,96 Ngudn Igi ddng val than inim khai thae dugc trong ddm Thuy Trieu gdm Gid bien (Gie do), Mirc la, Oc nhay, Sd bum (ngao) va cac loai sd khac. Tdng sdn lugng khai thdc cac doi tupng nguIn lgi nay trong ddm Thiiy Trieu dat khodng 148 tdn/ndm (bdng 6).
Rong cdu {Gracilaria spp.) cung Id mdt ngudn Igi ddng ke trong ddm Thiiy Trieu. Rong cdu lap trung nhilu d cac viing nude ven ddm thudc xa Cam Hda, Cam Hai Ddng va Cam Hai Tay vdi sdn iugng khai Ihac khodng 600 tdn khd/nam. Thdi gian khai thdc rong cdu nhieu la tCr thang 11 den thdng 5 am ljch.
Ngudn giong ghe trong ddm Thiiy Trilu rdt phong phu, chiing Ihudng xudt hi^n tir thdng I den thdng 2 am lich dgc theo dudng hd xa Cam Hdi Ddng, trong vung phdn bd cua thdm cd bien (Nguyin Xudn Hda, 2009).
HOl NGHI KHOA HOC T O A N Q U O C V £ SINH T H A I V A T A I N G U Y £ N SINH VAT L A N THCf 5 Bdng 6 San Iirgng 1^^> ^^^^ nguon Igi dpng vat than mem trong dim Thiiy Trieu
TT
1 2 3 4 5
D6i tipgng Gid bien (Gie ao) {Ungula sp.) Mg^ Id {Octopus sp.) 6c nhay (Strombus sp.) 86 bum (Ngao) (Marcia spp.) Thdn mem khde
Cong CM khai thdc Lan, xeng ddo Ld myc, rd, ludi.
B i t bang lay Cao bdng lay Cao b4ng tay
Mua vg khai thdc chinh
2-11 §m ljch 2-9 am ljch
2-5 §m \\ch Quanh nam Tfing cpng (tln/nam)
Sdn lugng (tdn/ndm) 63.38
1,60 3 50 30 147,98 Qua phong vdn cgng ddng cho thay do mdt rimg ngap man vd thdm cd bien bi suy thoai nSn ngu6n Igi thuy sdn trong ddm Thiiy Trieu ngdy cang suy gidm.
in.id;TLuAN
- Da xdc djnh 26 loai cay ng^p m^n tai khu vuc ddm Thuy Trieu, trong dd co 16 lodi cay nglp mdn th|it sg (true mangrove) va 10 lodi cdy tham gia rimg ngdp m|n (mangrove associates). Cac lodi Dude {Rhizophora apiculata). Dung {Rhizophora mucronata). Mam Irang {Avicennia alba) phd bien nhdt trong khu vuc ddm. Ddc biet Id su cd mat ciia lodi Cdc do {Lumnitzera littorea) quy hilm cd ten trong Sdch Dd Viel Nam 2007 cdn dugc bdo tdn d Viel Nam va cdc quoc gia tren thi gidi.
- Di?n tich rirng ngdp mdn d dam Thiiy Trieu da hi suy gidm nghiem trpng, hien chi cdn khoang 14ha phdn bd rai rdc ven dam.
- Da xdc dinh 8 loai cd biln trong dam Thuy Trieu vdi hai loai phd bien la Cd xoan {Halophila ovalis) vd Cd Id dira {Enhalus acoroides).
- Di?n lich cdc thdm cd bien trong dam khodng 547ha, phan bd chu yeu d Cdn Giua thupc vCing dinh dam va vimg nude ndng ven bd phia Ddng cua dam thugc xa Cam Hdi Ddng.
- Ngudn Igi cd chinh khai thdc dugc trong cdc tham cd bien va viing nude lan can gdm:
Cd bong, Ca dia, Cd ddi Id, Cd due, Cd gid, Ca liet, Ca mdm vdi tdng sdn lugng khai thdc khoang 338 tdn/nam.
- Nguon Igi thugc nhdm gidp xdc khai thae dugc gdm cd Cdng Idng, Cua hec, Cua xanh, Gh?, Tom dat vdi tdng sdn Iugng khai thdc khodng 495 tdn/nam.
- Nguon Igi dpng val thdn mem khai thdc dugc gdm Gid bien, Muc Id, Oc nhay, Sd bum (Ngao) vacac lo^i sd khac vdi tdng sdn lugng khai thdc khoang 148 tan/ndm,
TAI U£U THAM KHAO
1. English S.,C. Wilkinson and V. Baker, \994. Survey manual for tropical marine resources. AIMS, Townsville, Australia: 235-264.
2. Fortesm. D., 1993. Seagrasses: Their role in marine ranching. In: Seaweed cultivation and marine ranching. JICA. 131-150.
3. Nguyen XuSn H6a, 2009. Dilu tra thdng ke dien tich, thdnh phdn loai, danh gid hi?n irang phan bl h^ sinh thdi rimg ngap mSn, ihdm cd biln va vai trd cua chiing dii vdi kinh le-xa hpi, moi irudng d vung bien ven bd linh Khanh H6a-Dl xual gidi phdp qudn ly vd sir dung bin vung. Bao cao De dn mdi tru&ng tinh KhSnh H6a. 121 tr.
HQI NGHj KHOA HQC T O A N Q U 6 C V £ SINH THAl VA TAl NGUYEN SINH VAT L A N THl> 5 4. Nguyen Xudn H6a, 2010. Hien trang rimg ngap mSn d linh Khanh Hoa vd giai phdp phuc hoi. Tuyin
tap Hpi thao Qudc gia Phuc hdi vd Quan ly h^ sinh thai rimg ngap mSn trong bdi cdnh bien doi khi hdu. Cdn Gii^-Tp. Hd Chi Minh, 23-25/11/2010. Tr. 179-189.
5. Philips, R.C. and E.G. Menez, 1988. Seagrasses. Smithsonian Contribution to the Marine Sciences, No 34. Washington, D.C. 105 p.
6. Shozo Kitamura, Chairil Anwar, Amayos Chaniago, Shigeyuki Baba, 1997. Handbook of Mangroves in Indonesia. MEDIT, Tokyo Japan. I I9p
7 Vien Ngpc Nam, Nguyen Son Thuy, 1999. Nhan bilt cdy rimg ngap mjn qua hinh dnh. SdNong nghiep vd Phdi triln nong thon Tp. Hd Chi Minh. 102 tr.
8. WWF Chuong trinh Dong Duong, Hd Npi, 2003. S6 tay huong din gidm sdt va dilu tra da d^ng sinh hpc. 422 tr.
THE CURRENT STATUS OF MANGROVE AND SEAGRASS ECOSYSTEMS AT THUY TRIEU LAGOON, KHANH HOA PROVINCE
NGUYEN XUAN HOA, NGUYEN THl THANH THUY, NGUYEN NHAT NHU THUY
SUMMARY
In Thuy Trieu lagoon there are 26 mangrove species, of which 16 species are true mangroves. It is remarkable that Lumnitzera littorea is on the Red List of Vietnam and many other countries. The area of mangrove forest in Thuy Trieu lagoon is about 14ha, it distributes scattered along the shore. The seagrass beds in Thuy Trieu lagoon has 8 identified species, of which Enhalus acoroides and Halophila ovalis are most common. The area of seagrass beds in Thuy Trieu lagoon is approximately 547ha, it mainly distributes on Con Giua dune and the eastern shallow water of lagoon. Fish is mainly exploited in seagrass beds and neightbouring areas, including Acentrogobius sp., Siganus guttatus. Siganus canaliculatus.
Valamugit cunnesius, Sillago sp., Leiognathus sp., Gerres filamentosus with total production of 338 ton/year. The main exploited crustacean species include Uca sp., Charybdis anisodon, Scylla senata.
Poriunus pelagicus, Melapenaeus spp. with approximate total production of 495 ton/year. The main exploited mollusc species include Ungula sp., Octopus sp., Strombus sp„ Marcia spp, with approximate total production of 148 ton/year. Due to toss of mangrove forest and degradation of seagrass beds, Oie aquatic resources in Thuy Trieu lagoon more and more decrease.