Southeast Asian Fisheries Development Center Aquaculture Department
SEAFDEC/AQD Institutional Repository http://repository.seafdec.org.ph
Institutional Reports Quarterly Research Reports
1977
Reduction in Chaetoceros populations by furanace
Baticados, Ma. Cecilia L.
Aquaculture Department, Southeast Asian Fisheries Development Center
Baticados, M. C. L., & Gacutan, R. Q. (1977). Reduction in Chaetoceros populations by furanace. SEAFDEC Aquaculture Department Quarterly Research Report, 1(1), 36-37.
http://hdl.handle.net/10862/2283
Downloaded from http://repository.seafdec.org.ph, SEAFDEC/AQD's Institutional Repository
Reduction in Chaetoceros populations by furanace
By
M a. C e c ilia L. Baticados and R. Q. G acutan
O ne o f th e m o s t p r o m is in g p r o p h y la c tic agents b e in g te s te d t o c o n tr o l P en ae us m o n o d o n la rv a l diseases is fu ra n a c e [6 - h y d r o x y m e th y l- 2 2 ( 5 - n it r o - 2 - f u r y l) v in y l p y r id in e] . E a rlie r s tu d ie s o n th e use o f fu ra n a c e as a c h e m o th e r a p e u tic a g e n t a g a in st b a c te ria l and fu n g a l diseases o f fis h and fre s h w a te r p ra w n re ve a le d t h a t lo w c o n c e n tr a tio n s o f th is c h e m ic a l are n o n to x ic t o th e h o s t as w e ll as e ffe c tiv e a g a in st its diseases ( 1 , 2 , 3 ). T h e e ffe c ts o f lo w c o n c e n tr a tio n s o f th is c h e m ic a l f o r s p e c ific d u r a tio n s o f e x p o s u re o n P. m o n o d o n larvae have a lre a d y be en re p o rte d (4 ). T o e v a lu a te f u r t h e r its s u ita b ilit y as a c h e m o th e r a p e u tic a g e n t, its e ffe c ts o n th e p o p u la tio n g ro w th o f C h a e to c e ro s c a lc itra n s , th e d ia to m used as fe e d f o r th e zoeal stages, w as e x a m in e d .
C h a e to c e ro s p o p u la tio n s o f u n if o r m d e n s ity ( in it ia l d e n s ity in all ru n s : 1 3 0 - 1 4 1 x 1 0 3 c e lls /m L ) w e re p la c e d in n in e w h ite , c ir c u la r (3 8 2 sq c m ), p la s tic basins. T h e p h y s io -c h e m ic a l c h a ra c te ris tic s o f th e c u ltu r e w a te r w e re as fo llo w s : s a lin ity , 2 8 .5 - 3 0 .0 , p p t ; p H , 8 .6 2 - 8 .7 2 ; te m p e ra tu re , 2 3 - 2 5 .5 ° C ; d is s o lv e d o x y g e n , 7 .1 -9 .3 p p m ; n it r it e , 0 .0 3 -0 .0 7 p p m ; a n d a m m o n ia , 0 .0 0 5 - 0 .0 3 p p m . P re w e ig h e d fu ra n a c e g ra n u le s w e re d is s o lv e d in th e c u ltu r e w a te r, w it h re s u ltin g c o n c e n tr a tio n s o f 1 and 2 m g /L (3 re p lic a te s ea ch ). A set o f re p lic a te s w i t h o u t fu ra n a c e served as th e c o n t r o l. P o p u la tio n c o u n ts o f th e d ia to m w e re ta k e n a fte r 2 , 4 , 6 , 8 , and 10 h r e x p o su re s.
A f t e r 4 h r, th e p o p u la tio n de crea sed in all th re e le vels. T h e p o p u la tio n in 2 m g /L fu ra n a c e s h o w e d th e lo w e s t c o u n t an d t h a t in c o n tr o l th e h ig h e s t. T h e p o p u la tio n m ea ns are n o t s ta tis tic a lly d iff e r e n t f r o m o n e a n o th e r.
T h e p o p u la tio n c o u n ts s te a d ily d e c lin e d in th e fu ra n a c e b a th s and a fte r a 6 - h r e x p o s u re , th e m ea n p o p u la tio n d e n s ity in 2 m g / L w a s a lre a d y b e lo w th e in it ia l d e n s ity . P o p u la tio n c o u n ts in 1 a n d 2 m g / L are b o th s ta tis tic a lly d iff e r e n t fr o m th e c o n tr o l b u t n o t f r o m each o th e r.
A f t e r 8 h r, p o p u la tio n s in th e c o n tr o l and 1 m g /L de creased w h ile t h a t in 2 m g /L w a s a lm o s t th e sam e. N o s ta tis tic a l d iffe re n c e s e x is t a m o n g th e p o p u la tio n c o u n ts .
T h e fu ra n a c e b a th s cau sed f u r t h e r r e d u c tio n in p o p u la tio n a fte r 10 h rs e x p o s u re . T h e m ea n d e n s ity in th e c o n t r o l again in cre a se d a lit t le . T h e p o p u la tio n c o u n ts in th e fu ra n a c e b a th s d iffe r e d s ig n ific a n tly f r o m t h a t in th e c o n t r o l. A g a in , n o s ta tis tic a l d iffe re n c e e x is ts b e tw e e n th e c o u n ts in 1 a n d 2 m g /L . T h e p o p u la tio n m e a n in 1 m g /L w a s s lig h tly lo w e r th a n t h a t in 2 m g /L fu ra n a ce .
T h e m ea n d e n s itie s o f th e d ia to m p o p u la tio n s c o m p u te d fr o m a to ta l o f 19 tr ia ls are s h o w n in T a b le 1. T h e p o p u la tio n s in cre a se d in a ll tre a tm e n ts ( c o n tr o l, 1 m g /L , 2 m g /L ) a ft e r a 2 -h r e x p o s u re . T h e p o p u la tio n in th e c o n tr o l s h o w e d th e h ig h e s t c o u n t, fo llo w e d b y th o s e in 1 m g /L an d 2 m g /L . D iffe re n c e s w e re n o t s ta tis tic a lly s ig n ific a n t.
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