Tap chi Khoa hoc va Cong nghe bie-n T9 (2009). So 2. Tr 35 - 49
PHl'C HOI VA BAO TON RAN SAN HO O NAM VINH QUI NHON (BINH DINH)
\ 6 s i T U A N , NGUYEIN XUAN HOA, PHAN KIM HO.ANG V A HOANG XUAN BEN
Tom tat: Phuc hdi ran san ho trong khuon khd di tdi Nhd Nude KC-0907 dd duac lien hdnh o- vung bien phia Nam vinh Qui Nhan. ncri md rgn san hd suy thodi rdt nghidm trong do khai thac san hd de nung vdi. danh cd liuy diet vd khai thac thuy san qiid muc. Thu nghiem cho thdy vung bien Tdy Hon Ngang khdng the phuc hoi do su thay doi clidt luovg mdi trudng trong miia mua O hai vung thu nghiem cdn Igi (Nam Hon Ngang vd Hon Nlidn). cdc manh Idp dodn san ho eung dugc di ehuyen vd cd dinh tren nen san hd chc'l. cdc phien be long vd hon xi mang dd phuc hdi tot Ty le song cua san hd ednh Acropora dat tdi 85-100':!, trong mua khd vd khoang 6)0-80% trong niiui mua. San hd Porites nigrescens chung to su thich nghi kit trong cua 2 miia fun y rang cdc san hd cd dinh lien cdc coc sdl a ndn chdn ran cd tx le sdng thap do su di ehuyen cua cat Irong mua gid ddng bdc (Juan ly vdi su tham gia tich cue eua cdng ddng dia phuong dd mang Igi nhung tde ddng lich cue khdng clu qua phuc hoi nlu'tn too md cdn ddy nhanh qiid trinh phuc hdi tu nhien. Cdc san hd dang phiOn Montipora.
Echiuopora. Pachyseris, Echinopora va canh Acropora. Pin lies la thdnh phdn chinh tham gia vdo su phuc hdi tu nhien cua ran tr vung nghien cuu Mot dieu cdn phai quan Idm Id cdng viec phuc hdi san ltd ddi hoi nhieu cdng sue vd lien bae eung nhu su ung hd lich cue cua ciim;
ddng dia phuong
I. MO DAU
Ran san hd la mot trong nhirng he sinh thai quan trong bac nhat d viing bic-n nhiet ddi. Trong nhirng nam gan day cac ran san hd tren fhe gidi ndi chung va d Viet Nam noi rieng dang chin tinh trang sii\ thoai nang ne va tham chi bien mat d mot sd viing. Nhirng tiic ddng chinh la do boat ddng cua con nguvi bao gdm khai thac Iniy diet (diing chat nd, cyanua..), khai thac thu\ san qua mire, khai thac san hd, 6 nhiem. lang dpng tram tich, phat trien du lich thieu kiem soat... Ngoai ra cac tac ddng tir thien nhien nhu lii lut , bao to. sir tang cao nhiet do nude bien ciing gdp phan lain cho ran san hd suy thoai.
frirdc tinh hinh dd, nhieu giai phap khac nhau da dugc tien hanh nham bao tdn he sinh thai nay nham du\ tri tinh da dang sinh hgc va Igi ich kinh te ma ran san hd dem lai cho con ngirtTi. Mot trong nhirng giai phap dd la tien hanh cac boat ddng phuc hdi ran san hd. I)a\ la mot giai phap cdn tuong ddi mdi tren The gidi va ciing chi dugc tien hanh o' Viet Nam troiiL; thiri eian uan da\.
Ky thuat phuc hdi ran san hd dugc phat trien chii yeu nham cai thien tinh trang cac khu vuc ran bi pha huy do thien nhien (sir tan pha eiia sao bien gai, bao bien, hien tugng tay trang san hd) hay do con ngudi (nhu tau mac can, tha neo, danh bat buy diet, khai thac da san hd, d nhiem tire thdi). Khai niem phuc hdi khdng phai la mot y tirdng mdi, tuy nhien, cac chien luge dugc thuc hien khac nhau. Ndi chung, tat ca cac phuong phap deu ed chung muc tieu; cai thien do phii ciia san hd bang each hoac eung cap cac vat nen phii hgp de san hd bam, hoac eung cap ngudn san hd mdi, hoac chiet san hd tir nhirng tap doan Idn va ehuyen sang trong d nhung diem ran bj hu hai. Tuy nhien cdng viec nay can den sir thao tac true tiep ciia cac nha khoa hgc va cac thiet bj dat tien (nhu khi tai Ian SCUBA), nen chi phi cho viec phuc hdi van rat dat va chi thuc hien dugc d qui md nho (Heeger and Sotto, 2000).
Trong khudn khd ciia de tai cap Nha Nude KC 09 07. Vien Hai duong hpc da tien hanh thir nghiem phuc hdi san hd d viing bien phia Nam vinh Qui Nhon (tinh Binh Dinh) noi ma ran san hd dugc coi la da suy thoai dudi nhirng tac ddng nang ne do boat ddng ciia con ngudi. Quan diem tiep can dupe quan triet tir dau la phuc hdi phai di lien vdi quan ly va gan ket giua nha khoa hpc vdi cac nha quan ly dia phuong va cdng ddng noi trien khai nham tao thuan Ipi cho qua trinh thuc hien ciing nhu duy tri ket qua sau khi ket thiie nghien ciru thir nghiem. Bai bao nay eung cap nhirng dan lieu ve hien trang ran san ho, kha nang thich nghi ciia san hd phuc hdi va hieu qua sau qua trinh phi,ic hdi va quan ly.
Tang trudng kich thudc va khdi lupng ciia san hd phuc hdi se dugc cdng bd trong mot cdng trinh khac.
II. DIA DIEM VA PHUONG PHAP 1. Thoi gian vii dja diem
Thdi gian thuc hien dirge bat dau tir tir thang 7 nam 2002 den bet nam 2004. Trong dd. giai doan khao sat chgn dia diem va thir nghiem ban dau keo dai tir lite bat dau den thang 3 nam 2003. Khu vuc lua chgn bao gdm viing nude xung quanh dao Hon Ngang va Hon Nhan nam d phia Nam vinh Qui Nhon (hinh 1), gidi ban bdi toa do ciia 8 diem vdi kinh vT dp nhu sau.
Diem 1:13"40"36"" 109"14'5r" Digm 5;13"4ri2" 109"14'28""
Diam2:13"40"4r" 109'T4-58" Di^m 6:13"4r06" 109"14'09"
Digm3:13"40"56" 109"14'48" Di^m 7:13"40'52" 109"14'12"
Di^m4:13"4r06'" 109'T4-39" Digm 8:13"40'48" 109"14'24"
Tdng dien tich mat nude cho bao ve va phuc hdi san hd khoang 100 ha trong dd 20 ha dupe sir dung cho muc dich di trong san hd va tao ran nhan tao, dien tich cdn lai la
\iing bao tdn va quan ly khai thac hgp ly. Viing nude nay da dugc UBND tinh Binh Dinh
giao quan ly eho muc tieu bao ve va phuc hdi ran san hd vdi su phdi hgp quan l\ giira So Thuy san Binh Dinh, UBND phudng Ghanh Rang, thanh pho Qui Nhon va Vien Hai duong hgc.
2. Phuong phap khao sat va phuc hoi
Danh gia hien trang ran san hd trudc va sau phuc hdi dua tren cac chi tieu ve dp phu nen da\ ciia cac hgp phan sdng va phi sinh vat, mat do ca va sinh vat da\- ran san ho dugc lira chpn bdi phuong phap Reef Check (Hodgson & Waddell, 1997) va Mang ludi giam sat ran san hd toan cau (English et all, 1997).
Ky thuat phuc hdi bao gdm phuong phap di ddi san hd ciia Birkeland et al (1979);
Clack & Edwards (1995, 1999) va md hinh trang trai san hd cua Heeger & Sotto (2000).
Ket qua khao sat cho phep lira chpn ran cho d khu vuc Hon Khd (Nhon Hai) va Cii Lao Xanh. DaN' la mot sd trong nhung khu vuc it di d Binh Dinh eon cd sd Iugng san hd dang ke. Cac manh tap doan san hd dugc tach can than tir tap doan me d ran cho va van chu> en ve noi phuc hdi va dugc gan ket tren cac gia the nhan tao bao gom gan 200 tam be tdng (20cm X 20cm x 3cm) va 18 bdn xi mang dugc dat tren nen day cirng ciia ran, va 120 cgc sat cam tren nen day eat d chan ran. Ddng thdi eac manh tap toan ciing dugc gan true tiep tren nen san hd chet d nhung noi ed the trong viing ran bi suy thoai.
T. BINH DINH
V[NH QUI NHON
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Hinh 1. \'inh (,)ui Nhon \;i khu \irc phuc hdi - quan 1\' ran san hd
Vao thang 7. 2002, 374 manh tap doan san hd da dugc di ddi dem ve cd djnh tai hai vi tri phuc hdi d Tay Hdn Ngang \di 206 tap doan va d Nam Hon Ngang \di 168 tap doan. Vao thang 10. 2002, sd tap doan san hd sdng dugc di ddi bd sung den hai vi tri nghien ciru la 147 manh tap doan. Tir thang 5. 2003, phuong phap cd dinh san hd tren nen san hd chet dugc trien khai thir nghiem vdi sd manh tap doan di ddi den la 350 tai khu vuc Hdn Nhan. Tdng sd manh tap doan dugc cd dinh tren bdn xi mang d Hdn Nhan vao thang 4. 2004 la 62.
Qua trinh thir ngiem tai thuc dja do cac can bd ciia Vien Hai duong hpc va cae ngu dan tai chd tien hanh sau khi dugc hudng dan mot each cu the ve ca ly thuyet va thuc hanh cac phuong phap giam sat va phuc hdi ran san hd.
HI. KET QUA NGHIEN CUU VA THLT NGHIEM 1. Danh gia hien trang truoc phuc hoi
Dua vao ngudn thdng tin ve tinh trang khai thac va quan ly ran san hd d viing bien Binh Djnh do can bd dia phuong eung cap va nhirng ket qua khao sat mat rdng do Vien Hai duong hgc tien hanh trudc dd, viing ran d Hdn Ngang va Ian can da dugc khao sat danh gia chi tiet nham danh gia tinh can thiet ciia viec phuc hdi va quan ly ran san hd.
Khao sat nay eung cap cac dan lieu ve do phii cac hop phan day, hien trang ca va sinh vat day ran san hd eung nhu nhung thdng tin ve hien trang khai thac.
1.1. Do phii ciia cdc hop phdn ddy
Ket qua khao sat trudc khi trien khai phuc hdi cho thay day la viing bien ma dp phu ciia san hd thudc loai rat thap. Q Tay Hdn Ngang dp phii ciia san hd chi dudi 2%. trong khi dd phia Nam cd dp phii cao hon nhung eung chi khoang 5% (bang 1). Su khac nhau ve dp phii san hd giua hai ddi eung khdng khac biet nhau nhieu. Q Hdn Nhan, dp phu san hd d ddi ndng cd kha hon nhirng nhieu noi bao phii bdi cac bai san hd chet. Trong cae thanh phAn phi sinh vat, san hd mdi chet hau nhu khdng ed ma chi phii bdi san hd vd vun va da (luu y la san hd khdi chet da lau eung dugc coi la da trong chi tieu ciia ReefCheck). Dieu dd cho thay ran san hd virng nay dang bj suy thoai nghiem trpng trong thdi gian dai.
Bang Hop phan
diiy San ho cirng San ho mem San ho chet San ho %un Da
Rong Hai mien Bim Cat Dang khac
1. D p phii (%) Ciia cac hgp phan day d khu vuc thir nghiem Tay Hon Ngang
Doi nong 1,3
0 0 28,1 55,0 6.3
0 0 6,9 2,5
Do! sau 1.9
0 0 11.3 50.6 0.6
0 0 34.4
1,3
Nam Hon Ngang Doi nong
6,9 1,3 0 16.9 63,8 2.5
0 0 8.8
0
Doi sau 3.8 0.6 0 36.3 31.9 2.5
0 0 25
0
Hon Doi nong
17,5 3,13 1.25 10,6 52.5 0 0 0 10 1,25
Nhan Doi sau
2,5 0 0 19 67 0 0 0 11 0,6
1.2. Cd ran san hd
Vao thang 7/2002, mat dp ca ran san hd tai Hdn Ngang dugc coi la vao loai thap so vdi eac viing bi(3n khac (bang 2) va tai ea hai vj tri mat do ca d mat cat can deu Idn hon o mat cat sau. Trung binh tai Tay Hdn Ngang mat do ca la 288 ca the/500m" cdn phia Nam Hdn Ngang la 275 ea thCV500m-. Bang 2 ciing cho thdy mat do ca ran tap trung chu yeu vao nhdm kich thudc nhd ban 10 cm. Nhom kich thudc nay tai Tay Hon Ngang len dC-n 91,3% tdng sd, cdn phia Nam mat do eiia chiing chiem 85.4%.
KCn qua qua dgt khao sat ciing cho thay eac nhdm ca cd sd lupng nhieu d Hdn Ngang chii y^u thudc vao cae hp ca Thia (Pomaeentridae), Bang chai (Labridae) va ca Dia (Siuanidae). Trong khi dd, cac nhdm khac nhu ca Birdm (Chaetodontidae), ca Mil (Serranidae), ca Hdng (Lutjanidae) co so Iugng khong dang ke (bang 3).
1.3. Sinh vat ddy
Mat dp Ciic loai sinh vat da>' la chi thj hien trang ran san hd theo ky thuat ReefCheck tai Hon Ngang tuong ddi thip. Mat dp trung binh tai Tay Hdn Ngang dat 164 ea the/400m', trong khi phia Nam Hon Ngang chi cd 55 ca the/400m- (bang 4) . Thuc te. mat dp cac nhdm sinh vat day chi tap trung chii \i\\ vao nhdm Can gai den (Diadcnut), con cac nhdm cdn lai cd gia trj kinh te cao nhu Tom hiim, 6c tii \a... khdng con thay xuat hien.
Q Tay Hon Ngang Cau gai den cd sd Iugng cao hon a Nam hon Ngang
Bang 2. Mat do ca ran san hd (ca the / 500m2) theo kich thudc tai Hdn Ngang (7/2002) Dja diem
Tay Hon Ngang
Nam Hon Ngang Cii Lao Cham'*
Van Phong*
Nha Trang*
Cii Lao Cau*
Con Dao*
Phu Quoc*
Mat cat Sudn doc Nen chan ran Trung binh Suon doc Nen chan ran Trung binh
Nhom kich thu^oc
< 10 cm 333 192 263 301 136 219
10-20 cm 20 24 22 39 30 35
> 2 0 c m 3 3 3 4 4 4
Tong cong 356 219 288 344 170 257 540 676 226 346 2017
748 Chii thich: * Theo \'6 ST Tuan, Ngu\en Van Long va Nguyen Hu\' Yet (2005)
Bang 3. Mat dp cac nhdm ca ran san hd chii yeu (ca the / 500m2) tai Hdn Ngang (7/2002) Nhom ca
Ca Thia Ca Bang Chai Ca Biidm Ca Thien Than Ca Hdng CaMii CaDia
Tay Hon Ngang 81
54 5 8 2 3 33
Nam Hon Ngang 40
37 6 0 0 1 60
Nhin chung, ran san hd d khu vuc Hdn Ngang dang d trong tinh trang suy thoai nang ne vao thdi diem nam 2002. Theo dieu tra tir cdng ddng dia phuong, viing ran nay ehju nhieu ap lire trong thdi gian dai. San hd chet va ca san hd sdng dugc khai thac can kiet phuc vu nghe nung vdi - mot nghe truyen thdng d Tuy Phirdc , Binh Djnh. Tinh trang danh ca bang chat nd eung thudng xuyen xay ra. Thudng xuyen cd nhieu ghe Ian den khai thac sinh vat day ran va ea ran. Tinh trang neo dau tau thuyen tren ran la rat phd bien, nhat la vao miia gid ddng bac.
Vao thdi diem khao sat giira nam 2002, cae ran khao sat khdng cd tinh trang bj phii tram tich va thanh phan san hd cdn tuong ddi da dang vdi 27 gidng san hd dupe ghi nhan.
Dd la Montipora. Favia. Farites. Symphyllia, Porites, Leptastrea, GaUtxea, Pacliyseris, Hydnophora, Podabacia, Tiirbinaria. Goniastrea, Cypluistrea, Echinopora, Ecliinopliyllia. Eiipliyllia, Lithophyllon. Astreopora, Acropora. Merulina. Tiibastrea.
Pocillopora. Mostastrea. Platygyra. Pseitdosiderastrea. Acantbastrea vd Goniopora.
Ngoai ra cdn phan bd 2 gidng san hd mem la Sarcophyton, Sinularia. Trong sd tren, cd mot sd gidng chi cd the thich nghi vdi mdi trudng khdng chju tac ddng manh ciia lang dpng tram tich nhu Echinopora, Hydnophora dupe bat gap d Nam Hdn Ngang. Nliirng dan lieu nay cd the cho phep nhan xet rang viec phuc hdi san hd la cd the thuc hien.
Bang 4: Mat dp sinh vat day (ca the/400m2) tai Hdn Ngang thang 7/2002
Doi tuong
T o m b a c sT (Banded coral shrimp) Cau gai den {Diadema urchin) Oc dun (Troc/n/.s-spp)
Hai sam (Edible sea-cucumber) Sao bien gai (Crow of thorn starfish) Trai tai tugng (Giant clam)
6 c til va (Trion trumpet) Tom hiim (Spiny losber)
Tay Hon Ngang doi nong
0 120
5 0 0 3 0 0
doi sau 0 200
0 0 0 0 0 0
Nam Hon Ngang doi nong
0 45
1 0 0 2 0 0
doi sau 0 62
0 0 0 0 0 0
2. Thii' ngiem lua chon dja diem
Nhung danh gia dAu tien ve ty le sdng chung ciia san hd dugc phuc hdi tai Tay va Nam Hdn Ngang dirge thuc hien theo hai dpi bao gdm dpi 1 (7 - 10/2002, miia kho va gid tay nam) va dpi 2 tir thang 10/2002 den thang 3/2003 (miia nnra lii va gid ddng bae). Cac sd lieu chi tiet dugc trinh bay d bang 5. Tap hgp sd lieu cho tha> tai vj tri Tay Hdn Ngang, ty le sdng ciia san hd tuong ddi tdt trong dgt I (89,3% tren sirim ddc va 88,6% d n6n chan ran). Ngugc lai, toan bd san hd bj chCn khi kiem tra lai vao thang 3/2003. Sd san hd nay da bi tieu diet sau khi trai qua miia mua lii. Trong khi dd. d vi tri Nam Hdn Ngang san hd van duy tri dugc ehitni hudng kha quan trong ca hai dpi vdi 92,9 % d dtn I va 96,2% d sudn ddc ran va 74,3 % d nen chan ran trong dpi 2 (bang 5). Thanh phan thich nghi tot nhAt trong mdi trudng di ddi la Porites dang canh.
Tir thuc td nay, ed th(^ nit ra mot \ai nhan xet ban dau ve tinh thich nghi ciia san hd phiic hoi tai vimg thir nghiem nhu sau;
- Mac dii cd th6 cho rang vimg Tay Hdn Ngang da timg thuan Igi cho ran san hd tdn tai trong qua khir va trong thir nghiem miia khd nhung viec phuc hdi la khdng the do su tha\ ddi chat lirgng mdi trudng viio miia mua. Anh hudng eiia nude nggt va tram tich tir dat lic^n la yeu td bit Igi cho su phat trien eua san ho.
- Mdi trudng d Nam Hdn Ngang van cdn thuan Igi cho sir phuc hdi va phat trien ciia san hd ea trong tu nhien va phuc hdi nhan
tao. Tuy nhien, d ddi sau cua ran vdi mot sd viing nen day phii cat td ra khdng thuan Igi cho phat trien ciia san hd. Nguyen nhan cd the la do siJ xao trpn nen day va van due ciia nude trong miia gid ddng bac da lam cho ty le sdng giam nhieu.
Bang 5: Ty le sdng {%) ciia san hd phuc hoi Hdn Ngang trong nhirng thir nghiem dau tien
Vi tri
Tay Hon Ngang
Nam Hon Ngang
Tinh trang song
Song tot Song mot phan Tong con song Song tot Song mot phan Tong con song
7 - 1 0 / 2 0 0 2 Doi nong
37.2 52.1 89.3
Doi sau 44.3 44.3 88.6 86.6
6.3 92.9
1 0 . 2 0 0 2 - 3 / 2 0 0 3 Doi nong
0 0 0 64.6 31.6 96.2
Doi sau 0 0 0 26.5 47.8 74.3
3. Kha niing thich nghi va phiit trien ciia san ho phuc hdi
Tir ket luan Ircn, cac thu nghiem dugc tien hanh tiep tuc d Nam Hdn Ngang va mot diem khac dugc lira chgn bd sung la khu vuc Hdn Nhan. Danh gia ty le sdng eung dugc lam chi tiet hon cho timg loai gia the khac nhau va theo cac giai doan trong nam de tien so sanh (bang 6).
Bang 6. T\ le sdng (%) ciia san hd phuc hdi tren cac gia the khac nhau
Diem phuc hoi / kieu gia the (doi) 5 - 9 / 0 3 Nam Hon Ngang
Be long Nen san ho chet Be tong Coc sat
100 95,5
Hon Nhan Be tong (nong) Be tong (sau)
Nen san ho chet(nong) Nen san ho chet (sau) Coc sat (siiu)
100 86,9 92 100 93.5 Bon Ximang(nong)
Bon Ximang (sau)
9 - 4 / 0 4
71,4 60,5 40,3
3..7
76.7 40,5 80.4 75,0 34,5
4 - 7 / 0 4
92,0 88,5
93,3 - 98,6
100 16,1 100 97,2
Tir nhirng ket qua nay, cd the neu len cac nhan xet;
- Ve tdng the, t\ le sdng cua san hd phuc hdi vao miia kho thudng xu\en cao hon a miia mua \ a thdi k> gid miia ddng - bdc ddi vdi tdt ca cac loai gia the.
- Khu vuc Hdn Nhan ed ve thuan Igi hon cho sir tdn tai va phat trien ciia san ho cirng thir nghiem, tuy sir khac biet khdng nhicni.
- Gia the la san hd chet cd sin tren nin day ed xhi coi la tao mdi trudng dn djnh nhc4t va duy tri dircTc ty le sdng rat cao ca trong miia kho (90 - 100%) \ a miia mua (60 - 80%).
- Gia the la be tdng diic sRn ciing cho ken qua kha quan. ngoai trir khi dat a ddi sau do chju anh huong ciia sir xao trpn n(!n da\ (chi s6ng khoang 40% d Hdn Nhan). Viec dat cac tam be tdng trong khung vudng d Hdn Ngang eiing khdng hieu qua va cho t\ le sdng thap.
- Viec diing gia the la cac cpc sSt di cd djnh san ho tren nem da\ cat dugc coi la khdng phii hop vdi dieu kien d khu vuc thir nghiem. Nem cat d nem chan ran bj xao trpn nhieu trong miia gid ddng bac va gay chet san hd.
- Bdn xi mang, tuy mdi thir nghiem, da chirng to uu \ iet vdi ty le sdng cao (xap xi 100%) do dc cd djnh san hd va tranh dugc xao trcin d da\.
So sanh ty le sdng giira cac loai thir nghiem (bang 7) cho tha\ Poriics nigrescens cci tinh thich nghi tdt ca trong miia mua va ludn dat ty le song cao o hai diem thir imhieni. Hai loai Acropora nobilis va A. yongei giam ty le sdng trong miia mua ea o I Idn Nhan \a Nam Hdn Ngang. Ket qua theo ddi khdng eho thay cd sir khac nhau giira cac loai trong quan he vdi gia the cd djnh.
Biing 7. Ty le sdng (%) cua cac loai san ho phuc hdi theo thdi gian khac nhau Kliu vuc \ a
loiii thii' nghiem
Thang 4 - 9 / 2 0 0 3 Kiioang dao
dong Trung binh
Thang 9 / 2 0 0 3 - 4 / 2 0 0 4 Klioang dao
dong Trung binh
T h a n g 4 - 7 / 2 0 0 4 Khoang dao
dpng Irung binh Hon Ni'^anfi (San ho dugc co djnh tren de be tong \ a nen san ho chet)
A. nobilis A. yongei Pontes nigrescens
9 6 - 100 9 5 - 100
100
98 98.5
100
63 - 67 58 - 63 100
65 60.5
100
8 8 - 9 3 8 0 - 100
92
90.5 90,0 92,0
Hon Nhan (San ho dupe co dinh tren de be tong, nen san ho chet, coc sat \ a bon xi mang) A. nobilis
A. yongei Porites nigrescens
9 2 - 100 8 8 - 100
100
96,2 93,6 100
36 - 95 29 - 88 33 - SO
66,6 60,0 54.3
15.6- 100 2 0 - 100
100
86,8 88.0 100
4. Ran san ho sau hai nam phuc hoi va quan ly
Song song vdi viec phuc hdi san hd. nhirng boat ddng quan ly ciing da dugc tien hanh tir thang 10/2002. Mac dii van cdn mot sd van de can thao luan de nang cao hieu qua quan ly, sd lieu ve hien trang ran san hd thu thap trong hai nam qua da chirng td hieu qua nhat djnh. Minh chirng rd ret la su tha} ddi theo chieu hudng tich cue ciia quan xa ran san hd trong dieu kien tu nhien.
Do phu cua san hd
Co the nhan thay rang san hd cirng da cd dau hieu phuc hdi tu nhien kha tdt, nhat la d ddi ndng (hinh 2). Sau gan hai nam quan ly. do phu san hd o' ddi ndng Nam Hdn Ngang tang tir 5 len den tren 20"/o. Gia trj na\' ddi vdi Hdn Nhan la tir tren 10% (thang 5,'2003) len den gan 30% (6/2004). Ve thanh phan san ho phuc hdi trong dieu kien tu nhien, sd lieu giam sat cho thay cd sir khac biet rd ret giira hai diem. Ran Hdn Nhan chii \eu dupe phuc hdi nhd sir phat trien cua Porites. Echinopora. Acropora. Pachyseris. Cdn d Hdn Ngang, san hd phien Montipora ddng vai trd quyet djnh (binh 3)
35 30 25 20 15 10 5 0
n H o n Ngang (nong) n H o n Ngang (sau) n H o n Nhan (nong) n H o n Ntian (sau)
10.02 3.03 5.03 1,04 6.04
Hinh 2. Dien bien theo chieu hudng tich cue ve do phu san hd d Hdn Ngang va Hdn Mian
— Monlipora
— Acfopora Pontes Pachyseris
— Echirrapora
— Hydnophora
Hinh 3. Gidng san hd uu the trong phuc hdi tu nhien d I Idn Nlian (phai) va Hdn Ngang (trai)
Cd ran san lid
So sanh ket qua giam sat tai khu vuc Hdn Ngang theo thdi gian cho tha\ mot xu hudng gia tang ve tdng mat dp ca ran san hd d cac nhdm kich thirdc vao dpi giam sat thang 07/2004 (460 con/500 m" ) so vdi thang 07/2002 (275 con/500 m'). Trong do cac hp ca Thia Pomaeentridae. ca Birdm Chaetodontidae va ca Dia Siganidae cd sir gia tane dang ke hon so vdi cac hg ca Thien than Pomacanthidae, Bang Chai Labridae, Mil Serranidae va Hdng Lutjanidae (hinh 4 & bang 16).
;on/ 500 50nm'
400 300 200 100 0
0 07/2002 n 07/2004
Toagsoa I - 10cm 11 - 20cm > 20cn KMm kk'htl"PC"
Hinh 4. Cau triic kich thudc va xu the tang do phong phii ciia ca ran a I Idn Ngang Bang 16. Do phong phii theo nhdm ca (con/500 m') tren ran san hd 1 Ion Nuanu va I Ion Nhan
Nhom ca Ca Thia Ca Bang Chai
Ca Birdm Ca Duoi gai Ca Than tien
Ca Mil Cii Hong
Ca Mo Ca Dia
Nam Hon Ngang (7/2002)
40 37,5
6,3 - 0 0,6
0 - 60
Nam Hon Ngang (6/2004) Nong
208 35 26 39 2 2 1 12 53
Sau 82
9 10 17
~i
2 0 1 187
Hon Nhan (6/2004) Nong
309 71
6 38
3 4 0 3
Sau 169 22
6 19
1 7 1 0 10 1 10 Sinh vat day
Danh gia do phong phii ciia sinh vat day Idn tai Nam Hdn Ngang vao thang 7/2002, tilling 3/2003 va thang 7/2004 cho tha>, mat do chung cua cac chi tieu giam sat hau nhu khdng tha\ ddi nhieu, tuong irng theo thdi gian la 55 ca the/400nr, 57,5 the/400in* vii 52,5 thcMOOnr. Dieu kha quan la mat do cac nhom sinh vat cd gia trj kinh te cd sir tha>'
ddi tuong ddi rd theo chieu hudng tang dan va xuat hien them nipt sd loai cd gia trj kinh te khac (bang 17).
Bang 17: Mat dp cac nhdm sinh vat day (con/400m") tai Nam Hdn Ngang va Hdn Nhan
Loai sinh vat day Ion co gia tri kinh te Panulirus sp (Tom Hiim gai)
Trochiis niaciihitiis (Oc Dun) Trochuspynainis (Oc Dun)
Triadacna squamosa (Trai Tai lupng) Atrinci sp (Xuong)
Pinna sp (Ban mai)
Holothiiria nobilis (Hai sam) Holothitria ediilis (Hai sam)
Tripnciisics gratilla (Cau gai Sp dira) Tong cong
Ti le tren tong so sinh vat da\ Idn ("o)
Nam Hon Ng 7/2002
0 0.5
0 1 0 0 0 0 0 1,5 2.72
3/2003 0 3 0 0.5
0 0 3 0 0 6.5 11.30
ang 7/2004
0,5 1 0 0.5
1 3.5 0.5 0,5 2.5 10 19,04
Hon Nhan (7/2004)
0.5 3 2,5 0.5 3,5 2 0.5 0.5 0.5 13.5 5,86
5. Cac giai phap quan ly va ehuyen giao ket qua cho dja phuong Giao qiiyeii qudn ly mat nude vd xdy dirng qui che
De vice phuc hdi va quan l> co hieu qua, Viten Hai duong hgc da lam vice vdi cac co' quan chirc nang cua dja phuong ve viec giao qii_\en quan ly mat nude. Uy ban Nhan dan tinh Binh Djnh da ra quyet djnh giao mat nude cd thdi ban tai khu vuc Hdn Ngang cho Vien Hai duong hoc de thuc hien de tai khoa hgc. Ou\et dinh eung >eu cau Vien phoi hgp vdi Sd Thuy san. UBND thanh phd Qui Nhon. Chi cue Bao ve Ngudn Igi Thiiy san tinh va UBND phuinig Ghenh Rang xa\ dung qui che bao ve va sir dung. Vdi su phdi hgp dd.
Ul^ND thanh phd Qui Nhon da ra quyet djnh ban hanh qui che quan ly vii bao ve khu phuc hdi va bao tdn ran san hd Hon Ngang. De thuc hien qui che. Chi cue Bao ve Ngudn Igi Thu_\ san tmh Binh Djnh da tang cudng boat ddng truyen thdng nham khuyen cao eho ngu dan \a tuan tra kiem soat trong khu \ irc Hdn Ngang.
Phdn vung phuc hdi vd sii dung
Tren co' so' nhirng khao sat \'a thir nghiem ban dau. viing nude trong khu phuc hdi va bao tdn ran san hd da dugc phan chia thanh hai \img; khu \irc phuc hdi ran san hd (bao \'e nghiem ngat) \a khu \irc bao tdn tu nhien (khai thac hgp ly). Uy ban Nhan dan Thanh pho Qui Nhon da ra Quyet djnh ve qui che quan ly vdi cac dieu khoan khac nhau phii hgp vdi chirc nang ciia timg phan \'irng.
Sty tham gia cua cdng ddng
Cong ddng thdn Bai Xep da tham gia boat ddng phuc hdi va quan ly ran san hd ngay tir khi bat dau. Cac tha Ian nmr dan diroc dao tao ca ve Iv thuvet bao tdn thien nhiC-n \a
thuc hanh phuc hdi san hd. Vdi sire lire ciia minh, hp da ddng gdp mot phan danu ki5 trone qua trinh lam viec nang nbpc dudi nude. Qua cdng viec, ngu dan dja phuong da tu nanu cao nhan thirc va cd trach nhiem hon trong viec quan ly khu phuc hoi va bao tdn ran san hd Hdn Ngang.
Duy tri boat ddng qudn ly
Hai nam da qua va boat ddng khoa hpc da ket thuc. Mot vin dk dat ra la lam tb§ nao de duy tri boat ddng ben vung ciia khu phuc hoi va bao ton ran san hd. Trudc mat. Vien Hai duong hpc da de nghi co quan cd thSm quy6n cua tinh ra qu>it djnh thanh lap Ban quan ly Khu phuc hdi va Bao tdn ran san hd Hdn Ngang d^ tiep nhan ehuyen giao kk qua nghien ciru khoa hpc. Viec quan ly khu vuc nay tiep theo rSt chn sir tham gia cua cac ben lien quan. Trong dd. nganh Thiiy san se ddng vai trd ehu dao .xay dung md hinh quan ly cd su tham gia cua cdng ddng vdi su ho trg ky thuat ciia Chi cue Bao ve Ngudn Igi Thuy san. Hien nay, mot vai doanh nghiep du Ijch dang budc dau khai thac khu vuc Hdn Ngang cho du Ijch bien. Ban quan ly can cd ca cha de gan trach nhiem ciia doanh nghiep du Ijch vao viec duy tri ben vung tai nguyen.
IV. KET LUAN
Bao ve va phuc hdi ran san hd d viing nude khu vuc Hon Ngang (phia Nam thanh phd Qui Nhon, tinh Binh Dinh) da dugc tien hanh gan hai nam. Vien Hai duong hgc da phdi hgp vdi sd Thuy san tinh va chinh quyen dja phuong huy ddng sir tham gia eua cdng ddng vao viec phuc hdi va bao ve ran san hd tuong ddi co hieu qua.
Viec di ddi san hd cirng de phuc hdi nhan tao cho ket qua kha quan ve ty le sdng. Ky thuat gan cac manh tap doan san hd tren nen san hd chet cd the coi la hieu qua nhat ve ky thuat va kinh te. Tuy nhien, ddi vdi viing ran cd nen day vd viin, vice sir dung cac bdn be tdng va de be tdng la giai phap chgn lira.
Viec bao ve va phuc hdi ran san hd d Nam \jnh Qui Nhon tinh Binh Dinh la kha thi. Ket qua budc dau cho tha\ trien vpng cd the phuc hdi lai mot sd viing ran bj suy thoai nhu d viing bien Hdn Ngang va Hon Nhan. Tuy nhien, ran phia Tay Hdn Ngang kho co the dugc phuc bdi do tac ddng manh cua nude nggt va ga\ due vao miia mua lii. Ket qua thi nghiem d day cdn phan anh sir su>' thoai ran san hd do thay ddi chat lupng mdi trudng va cd th6 cho rang nhirng boat ddng ciia con ngudi tren dat lien cd the huy diet vTnh vien nhieu vimg ran.
Viec phuc hdi nhan tao la mot giai phap cap bach nhung can nhieu sire lire va tien eua. Chinh vi vay, viec giir gin cac vimg ran cdn tuong ddi nguyen ven la bet sire can thiet.
Song song vdi phuc hdi nhan tao, cac giai phap bao ve vdi sir tham gia ciia cdng ddng se gdp phan thiic day qua trinh phuc hdi tu nhien tai nhirng viing thir ngiem phuc hdi.
Trong thdi gian tdi, cac boat ddng bao ve va phuc hdi ran san hd tai viing bien Hdn Ngang can dugc duy tri va md rdng. Vdi su quan tam ciia chinh quyen dja phuong, cae giai phap quan ly dang dugc hoan chinh de xay dijng trgn ven md hinh cdng ddng bao ve va phuc hdi ran san hd phtjc vu cho bao tdn da dang sinh hpc va phat trien kinh te.
TAI LIEU THAM KHAO
1. Birkeland, C , R.H. Randall and G. Grimm (1979). Three methods of coral transplantation for the purpose of reestablishing a coral community in the thermal effluent area at the Tanguisson Power Plant. Univirsity of Guam. Tech. Rep. 60.
2. Clark S. and A. J. Edwards (1995). Coral transplantation as an aid to reef rehabilitation. Evaluation of a ease study in the Maledve island. Coral Reef 14, 201 - 213.
3. Clark S. and A. J. Edwards (1999). An evaluation of artificial reef structures as tools for marine rehabilitation in the Madives. Aquat. Conserv. Mar. Fresh. Ecosys.
9 , 5 - 2 1 .
4. English S., C. Wilkinson and V. Baker, 1997. Survey manual for tropical marine resources. Australian Institute of Marine Science. Townsville. 390 pp.
5. Heeger T. and F. Sotto, (2000). Coral farming. A tool for Reef Rehabilitation and Community Ecotourism, 98pp.
6. Hodgson G. and S.Waddcll, 1997. International ReefCheck Core Method.
7. V6 ST Tuan (chu bien), Nguyen Huy Yet va Nguyen Van Long (2005). He sinh thai ran san hd Bien Viet Nam. NXB Khoa hpc va Ky thuat, Chi nhanh thanh phd Hd Chi Minh, 212 trang.
Lo'i cam on: Nhdm thuc hien chan thanh cam on su hd trg kinh phi ciia de tai KC.09-07 do PGS TSKH Nguyen Tac An lam chii nhiem; su hgp tac tich cue va hieu qua ciia Sd Thiiy san, Sd Khoa hgc Cdng nghe, Chi cue Bao ve Ngudn Igi Thuy san tinh Binh Djnh, UBND Thanh phd Qui Nhon, UBND phudng Ghenh Rang va su tham gia nhiet tinh va vd tu ciia cdng ddng nhan dan thdn Bai Xep
REHABILITATION AND MANAGEMENT OF CORAL REEFS IN SOUTHERN QUI NHON BAY (SOUTH VIETNAM)
VO SI THAN, N G U Y E N XUAN HOA, PHAN KIM HOANG & HOANG XUAN BEN
Summary: An extensive rehabilitation was practiced during 2002 - 2004 in southern Qui Nhon bay of coastal Binh Dinh province where coral reefs had suffered serious degradation due to coral mining, destructive fishing and overfishing. The first experiment indicated thai the nearshore reefs in the western part could not be rehabilitated due to environment change during rainy season with large discharge of sediment and freshwater.
Transplanted hard corals adapted well in southern part of island Hon Ngang and Hon Nhan with the techniques that used dead coral substratum, concrete plates and revered tubs as the attachments of corals. Survival rate of branch corals Acropora was quite high in dry season (85-100%) but reduced during rainy season (60-80%). Meanwhile Porites nigrescens presented good adaptation to environment seasonal change. The corals which were fixed with steel sticks on reef platform had low survival rate due to sediment movement in north-east monsoon. The concurrent site managemenl with strong supports from local government and communities has brought positive effectiveness of reef rehabilitation thank to not only coral transplantation hut also natural recovery. Foliose corals belonging to Montipora, Echinopora. Pachyseris. Echinopora and branch Acropora, Porites play an important role of natural rehabilitation. The activities, however, require hard work and expensive cost as well as sympathy of local people.
Ngdy nhan hdi: 28 -10 - 2008 Dia chi: Vien I lai duong hpc Ngiari nhan xet: PGS.TS. Nguyen I luru Phung
