Judul: Peran ikan mas (Cyprinus carpio L.) betina untuk merangsang pemijahan ikan tawes (Barbonymus gonionotus B.) dalam metode Cangkringan
Abstrak: Natural spawning in fish is more preferable than induce breeding. Cangkringan method offer an alternative that very close to natural spawning, since this method using spawning common carp to stimulate java carp to spawn. The stimulation most likely caused by pheromone which released from common carp. The use of pheromones in fish spawning has a highly practical because it can be applied without handling fish too much thus eliminating stress, and stimulate the endogenous normal processes of mature brood stock that eliminating failures in fertilization. Stimulation of spawning by pheromones potential to be developed further on mass spawner fish. The evidence of pheromones of common carp spawning in Cangkringan method may cause primary responses or releaser responses in Java carp to spawn, which in turn cause spawning of Java carp. In induce breeding, either by using hypophyzation technique or other gonadotropin hormone has several disadvantage. For using pituitary gland, the weakness are the loss of donor fish because it was taken their hypophysis, standardized pituitary gland extract is difficult to do because there are too many hormones involved, there are fears of an interaction among the hormones, and disease transmition. Spawning fish using Cangkringan method have several advantages such as reducing stress and avoid mortality risk, repeating inducer for spawning several times, and providing alternative to develop pheromones as an inducer. However, it is not clear until now the control of female common carp to induce spawning of Java carp in Cangkringan method. Therefore it is important to find the responsible pheromone in future. This study aimed to evaluate control of female common carp to induce spawning of Java carp in Cangkringan method. Each pair of Java carp was placed in the same tank with three common carp (♂♂♀ or ♀♀♀) injected or not injected with ovaprim. Between common carp and Java carp, they were separated by net. This study consist of three treatments, and two controls with three replications. The composition of this treatment were ♂ ♂ ♀ not injected (A), ♂ ♂ ♀ injected (B), ♂ ♂ not injected and ♀ injected ( C), ♀♀♀ injected (D) and ♀ ♀♀ not injected (E). Sampling for egg was conducted before the first injection by cannulation tecniques. Observation indicated that egg diameter ranged from 0.99 to 1.96 mm for common carp eggs, while the diameter of Java carp eggs ranged from 0.67 to 0.75 mm. Results of this study showed that fish which act as inducer spawning in Cangkringan method is common carp because Java carp would spawn only if common carp was spawn. The Java carp never spawn precedes before common carp. These results indicated that inducing of common carp on spawning of Java carp enabled due to ovulating heterosexual couple carp (♂♂♀) or ovulating couples monosex (♀♀♀). The fastest interval time induction of common carp on natural spawning of Java carp indicated by B3 treatment is 6 hours 55 minutes, then E3 is 6 hours 58 minutes, and C3 is 8 hours 5 minutes Analysis of testosterone and estradiol showed that testosterone concentration of male common carp and estradiol concentration
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