Southeast Asian Fisheries Development Center Aquaculture Department
SEAFDEC/AQD Institutional Repository http://repository.seafdec.org.ph
Institutional Reports Quarterly Research Reports
1979
Culture experiments on the copepod,
Tisbintra elongata MORI, and evaluation of that species as food organism for
milkfish larvae
Yamasaki, Shigehisa
Aquaculture Department, Southeast Asian Fisheries Development Center
Yamasaki, S., & Canto Jr., J. (1979). Culture experiments on the copepod, Tisbintra elongata MORI, and evaluation of that species as food organism for milkfish larvae. SEAFDEC
Aquaculture Department Quarterly Research Report, 3(4), 17–20.
http://hdl.handle.net/10862/2359
Downloaded from http://repository.seafdec.org.ph, SEAFDEC/AQD's Institutional Repository
C u lt u r e e x p e r im e n t s o n t h e c o p e p o d , T i s b i n t r a e lo n g a t a M O R I , a n d e v a lu a t io n o f t h a t species as f o o d o rg a n is m f o r m il k f is h la rv a e
S h ig e h is a Y a m a s a k i* a n d J o s e C a n t o , J r .
Five types o f food were used to culture Tisbintra elongata: rice bran, cow dung, bread yeast, fermented fish solubles and S pirulina sp., T. elongata were cultured b y tw o methods; one in 200 m L beakers and another in 30 L plastic pails. The rate o f feeding at a p proxim ately 0.01 mg d ry weight per individual fo r copepodite and adult stage (Ito h , 1973) were used. The in itia l starting density was 0.4 to 0.6 in d /m L . A fte r 16 days period, the e ffe ct o f the five kinds o f food were evaluated. Results show th a t bread yeast gave the highest density fo llo w e d b y rice bran, Spirulina, cow dung and fermented fish solubles.
Determ ination o f the o p tim u m feeding amounts fo r rice bran and ferm ented fish solubles was carried o u t in 30 L pails. Three d iffe re n t rates o f feeding w ith these tw o types o f fo o d were used. Results (Fig. 1) show th a t the population density o f T. elongata was highest when fed w ith 0.125 x 5 m g/ind per day o r rice bran and 0.27 m g/ind/day o f ferm ented fish solubles.
The e ffe c tiv ity o f rice bran and fermented fish soluble fo r the o u td o o r mass culture o f T. elongata was evaluated. For rice bran, tw o 1-ton tanks were used w hile tw o 350 L tanks were used fo r fermented fish solubles. A fte r bloom ing o f Chaetoceros sp. had occurred in tw o 350 L tanks supplied w ith fermented fish solubles, copepods were inoculated at 0.05 in d /m L . Shelter in fo rm o f nipa leaves was provided in one ta n k. A feeding rate o f 0.27 m g /in d /d a y rice bran was used in both tanks. Sim ultaneously in another tw o 1-ton tanks copepods o f the same density were inoculated, one tank was provided w ith "n ip a leaves" as shelter. The feeding rate o f 0.4 mg/
ind per day was used. A remarkable increase in the population density o f copepods fed w ith fish soluble was observed during the firs t half o f the culture period w h ich lasted fo r 12 days. The highest density obtained was higher in the tank provided w ith shelter than th a t w ith o u t shelter.
The densities obtained were 10.0 and 8.0 in d /m L respectively. However, in the la tte r half o f the culture period, the density declined rapidly in both tanks. T. elongata fed w ith rice bran increased rapidly to 9.5 ind per m L /d a y in all tanks provided w ith shelter; b u t in the tank w ith o u t shelter, there was no observed increased in density. Instead, the density decreased after reaching the peak o f 1.9 in d /m L .
* Laboratory o f A quaculture Physiology, Faculty of Fisheries, Kagoshima U niversity, Japan.
Fig. 1 . P o p u la tio n g ro w th o f T is b in tr a fee din g on d iffe re n t am ou n ts o f rice bran and fe rm e n te d fish solubles.
The sa lin ity tolerance o f T. elongata was also investigated. Results indicate th a t T. elongata could tolerate salinities as low as 13 p p t and as high as 67 p p t when transferred im m ediately fro m th e ir natural habitat to the experimental co n d ition . However, those cultured in the tanks could tolerate salinities only as low as 31 p p t or 44 ppt. A com parative study on the grow th and survival rate o f m ilkfish fr y fed w ith the copepod T. elongata and brine shrim p, A rte m ia salina was also evaluated. M ilkfish fr y w ith bo d y length ranging fro m 12.3 mm to 13.5 mm w ith a mean w eight o f 7.6 mg were used fo r this study. Feeding o f the fry were made tw ice d a ily at the rate o f 4, 20 and 40 times the larval saturation. There were tw o replicates fo r each tre a tm e n t and the feeding experim ent lasted fo r 2 weeks. Results(Fig. 2, 3) indicate th a t there are no significant differences in the grow th and survival o f m ilkfish fr y fed w ith A rte m ia o r w ith the copepod T. elongata.
F ig . 2 . S u rv iv a l ra te o f m ilk fis h la rva e fe d o n T is b in tr a a n d A r t e m ia in 1 0 L a q u a ria . I : T r e a tm e n t a t lo w fe e d in g ra te
II : T r e a tm e n t a t m e d iu m fe e d in g ra te I I I : T r e a tm e n t a t h ig h fe e d in g ra te
Fig. 3 . M ean b o d y w e ig h t and length o f m ilk fis h f r y in each tre a tm e n t.
L ite ra tu re C ited
Ito h , K. (1973): Food experiments fo r copepods estimated fro m their m etabolic rates. Bull.
Plankton Soc. Japan, 20, 78-83.
