Southeast Asian Fisheries Development Center Aquaculture Department
SEAFDEC/AQD Institutional Repository http://repository.seafdec.org.ph
Journals/Magazines Aqua Farm News
1994
Cage culture of sea bass in Malaysia
Aquaculture Department, Southeast Asian Fisheries Development Center
Southeast Asian Fisheries Development Center, Aquaculture Department (1994). Cage culture of sea bass in Malaysia. Aqua Farm News, 12(1), 12, 15.
http://hdl.handle.net/10862/2497
Downloaded from http://repository.seafdec.org.ph, SEAFDEC/AQD's Institutional Repository
TECHNOLOGIES FOR FARMING THE SEA
fe e d s re p re se n t 40-60% of total operating costs.
T h e m arket and other fa cto rs m ust be able to ju s tify th e high cost of fe e d s involved.
Variations of the theme
M ore and m ore syste m s are now co m p le te ly integrated. U nits fo r staff a cco m m o d a tion, p o w e r generation, a u tom atic o r c o m p u te r
ized feeding, fe e d storage, and fish grading and tra n s p o rt e quipm en t are built together. In a
vacuum pum p system , fish are sucked into a hose and into a so rte r that rem oves the w ater and size grades th e fish. T his m inim izes dam age during tra n sfe r of fish to cages or boats.
S om e farm s use a com puter program in stock m anagem ent. T he program sim ulates biom ass chan g e s during th e grow th cycle and records stocks and feeds.
Source: F Buranudeen. The basics o f cage and pen culture. INFOFISH International 2/89.
Cage culture of sea bass in Malaysia
Sea bass 5-8 cm long are stocked in ca g e s a t d e n sitie s of 15-25 fin g e rlin g s per m 3.
A fte r several w eeks, d ensities are reduced to 10-23 p e r m 3. A lthough th e re is a large g o v
ern m e n t hatch e ry and som e local seed su p p li
ers, th e bu lk of sea bass sto ck is im ported from ne ig h b o rin g countries, especially Thailand.
Sea bass are fed "trash fish" once a day.
A s th e y grow , sea bass are periodically graded to p revent canniba lism .
S ea b a ss a ttain m arketable size (500-600 gram s) in a bout 6-8 m onths. S urvival is 60-80% . T h e y a re m arketed live in local restaurants or e xp orted to S ingapo re. T he ex-farm selling price is around M $ 9-10 p e r kilogram .
Problems
F orem ost am ong th e problem s are feed and seed. "T rash fish" is th e m ain source of feed fo r the c a g e cu ltu re industry; supply is lim ited
and the quantity and price subject to seasonal variations. A lthough a n um ber of prepared feeds have been introduced by both the governm ent and the private sector, th e ir use has not quite caught on, m ainly because of high cost and d oubts about th e ir efficiency.
M ost of the seed supply is fro m Thailand and the longer transport tim e m eans stress.
T ransport costs add to the price of the fry. The governm ent encourag es and provides training in hatcheries. M any have already set up their ow n sea bass hatcheries a fte r attending the governm ent courses.
A n other problem is overcrow ding o f fish cages in a particular area. W ater flow is hin
dered, resulting in accu m u la tio n of feces and uneaten food. Excessive stocking and feeding by som e o verzealou s but m isguided culturists fu rth e r w orsens the problem . O vercrow ding and poor w ater quality stre ss th e fish and they suc
p. 15 Cages are generally
rectangular and are made of polyethylene nets. Their sizes vary: 3 x 3 x 2 m, 4 x 4 x 3 m. The estimated cost of one platform (4 cages of size 3 x 3 x 2 m) is MYR 2000-2500.
12 Aqua Farm N ew s Vol. XII (No. 1) January-February 1994
TECHNOLOGIES FOR FARMING THE SEA
Pearl culture in abalone
Pearl culture in th e abalon e H aliotis is carried out in Japan, K o
rea, C a n a d a , and the U nited States. T he q u a l
ity of abalon e pearls, as d e te rm in e d by s u rfa c e te x tu re , is s u p e rio r to those produced in fre sh w a te r m ussels and c o m parable to th o se of th e m arine pearl o yste r Pinctada. A ba lo n e pearls are priced at about U S $ 3 0 0 fo r a 1 3 - m illim e te r A A A g ra d e sem ispherical o r m abe piece.
T he fa rm e r can grow pearls in 6-8 cm abalon es fo r a y e a r o r so. T his size of abalone, how ever, ta ke s about 3 years to grow. H atch
ery-bred a balon e seed cost C anadian $16 per pound. Pearl culture can take 3-18 m onths depending on w ater tem perature, and age and food of abalone. But th e abalone can be sold as food, and production co sts can be m ore than offset by th e price of th e pearls.
P earls are produced by nucleation, w here plastic, soapstone, o r m other-of-pearl is slipped beneath the m antle epithelium o f the abalone.
T he nucleus m ust be secured a gainst th e m o ve m ent of th e a b a lo n e 's m u scu la r foot. Follow ing nucleation, th e m obile a b alon es a re placed in a secure enclosure to prevent th e ir escape. In British C olum bia and C alifornia, screened p la s tic drum s suspend ed in th e sea are used. A b a lones m ust be fed at least w eekly w ith th e kelp M a c ro c y s tis, a nd th e s e a w e e d s G ra c ila ria , Lam inaria, and N ereocystis. F ouling organism s, sea stars, and octo p u se s m ust be regularly rem oved fro m th e culture area.
W ithin several d a ys fo llow ing nucleation, a thin chalky layer is secreted against and around the nucleus. Then, a thick, ta n -b ro w n la ye r of conchiolin is deposite d. C o n chiolin fo rm s th e founda tion fo r a layer of porcelain-like, p rism a tic a ra g o n ite crysta ls, and a la y e r of na cre o u s aragonite. In a properly cu ltured a b a lo n e pearl, the conchiolin is about 1 m m thick. In V a n c o u ver, sem ispherical pearls can be cu ltu re d in H aliotis kam tschatcana to a d ia m e te r of 17 m m . In Japan, pearls can be grow n to 22 m m in H aliotis discus.
Source: P Fankboner. Pearl culture in abalone.
INFOFISH International 4/91.
New Zealand
A m ussel fa rm is usually 3 hectares with 10 surface longlines. T he fa rm is sited in areas with a current flo w of 0-4 knots, in unexposed, sem i-enclosed bays and m oderately exposed open seas w ith d e p th s of 5-4 0 m eters. Spats are collected w here they are abund ant by “catching ropes" and tra n sfe rre d to farm s. It ta ke s 1-6 m onths fo r th e m ussel to grow to the ideal reseeding size of 10-20 m m . T he m ussels take 10-12 m onths to grow to m arket sizes in reseeded lines.
S ource: P L arge. M u s s e l c u ltu re su cce ss. IN F O F IS H In te rn a tio n a l 4 /8 9.
SEA BA S S CAG ES IN M ALAY SIA ... F R O M P A G E 12
c u m b e a s ily to d is e a s e s a n d p a ra s ite s . M a ss m o rta litie s of fish have o c c u rre d in a n u m b e r of c a g e farm s.
Cage culture booms, nonetheless
In spite of th e se p ro b le m s, se a bass fa rm in g has so fa r m a naged to su sta in its b o o m in M alaysia.
In 1989, th e s e a bass p ro d u ctio n of 1538 to n s w as 2 1 % h ig h e r th a n t h e p re c e d in g year. In fa ct, p roduction has b een in cre a sin g s te a d ily o ve r th e last 5-6 years.
W ith g ood m a n a g e m e n t and atte n tio n to s o m e of th e p ro b le m s b e in g fa ce d , th e re is e ve ry lik e lih o o d of a fu rth e r increase in p ro d u ctio n in th e fu tu re .
Source: T Singh. M alaysia enjoys the sea bass boom. INFOFISH International 2/91.
Aqua Farm News Vol. XII (No. 1) January-February 1994 15
