Biologi pembiakan ikan terbul osteochilus hasselti (C. & V.) di Tasik Chenderuh, Perak.
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Date
1997-04
Authors
Zakariah, Zahaitun Mahani
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Abstract
A study on reproductive biology of terbul. Osteochilus hasseltt had been carried out at Tasik
Chenderuh by using certain approaches such as gonadosomatic index (GSI), hepatosomatic
index (HSI), condition factor (K) and histological obervation. Effects of environmental factors
such as rainfall and water level in relation to spawning activities were also studied.
Histological observation showed that female terbul is an asynchronous spawner. Oogenesis in
terbul is described in seven stages: oogonium, chromatin nucleolus, yolk vesicle, yolk granule,
matured oocyte and atretric. The testis consists of five maturity stages: spermatogonia,
primary spermatoc:yte, secondary spermatocyte, spermatid and spermatozoa and is categorized
as "unresrtricted spermatogonial testis-type". Due to the mixing of spermatid and spermatozoa,
it is also identified as a "semi-cystic testis". Females showed a more distinct reproductive
pattern compared to males. Analysis through histology and GSI indicated three spawning
seasons in October 1993, April 1994 and September 1994. The histological observation on
testis did not show any maturity changes since it consist of spermatozoa throughout the year
given suitable environmental condition. The continous recruitment of yolky oocytes and the
availability of spermatozoa in these fish indicates that spawning activity is possible at
anytime. The HSI and K showed that storing of nutrients in liver and muscle has no influence
on the gonadal maturity as compared to temperate species. Since food is always available
throughout the year, the liver and mucles do not play active roles during gonadal
development. The fecundity of terbul range from 7, 733 to 42, 888 ooc:te per female whereas
the relative fecundity is 81 to 366 oocyte per gram. The fecundity is not affected by total
length (r = 0.58) and body weight (r = 0.66, P < 0.05)
Water level is not influenced by rainfall (r = 0.3422, P > 0.05) due to the management ofthe
hydroelectric power station. Water level fluctuation has a greater influence on spavming
activity as compared to rainfall. The GSI of female showed a positive correlation with water
level (r = 0.5402, P < 0.05). Spawning activity still occur despite of poor rainfall, as long as
the ecotone is submerged due to water retention in the dam.
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Keywords
Pembiakan ikan terbul , Osteochilus hasselti (C. & V.) , Tasik Chenderuh, Perak