Judul: Peran Ikan Mas (Cyprinus carpio L.) Jantan dalam Merangsang Pemijahan Ikan Tawes (Barbonymus gonionotus B.) dengan Metode Cangkringan
Abstrak: A method to induce spawning in fish is a stimulation through other spawning fish which known as the Cangkringan method. This method is still a natural spawning that effective and safe for reducing stress, lowering mortality risk, and using common carp as inducer for spawning of Java carp (Zairin et al. 2005). The inducing system was developed by BBIS Cangkringan, Sleman, Yogyakarta in the early 1970's. This method is performed by using common carp spawning in the same tank with the java carp which is relatively difficult to be spawned. The results showed that Java carp will spawn following spawning of common carp. Pheromone released by common carp was suspected as a responsibile factor for java carp to spawn (Zairin 2003). The spawning behavior indicated the influenced of pheromones (chemical signals released by a type of fish) (Stacey and Sorensen 2005). The use of pheromones in fish breeding is very practical value because it can be applied without directly handling the fish, it reduce stress and stimulate normal endogenous processes that reduce spawning and fertilization failure. This condition only works on the parent good maturation. The spawning stimulated by pheromones is very potential to be developed in mass spawner fish (Zairin 2003). Therefore it should be developed to find the source of pheromones that can be used as an inducer on fish spawning. Nowadays, the role of male common carp in stimulating the java carp spawning by Cangkringan method is yet not understood. Based on the above problems it is necessary to study the role of male carp to stimulate Java carp spawning with Cangkringan method. The experimental design used RAL design consisting of five treatments with three replications. Each pair of Java carp parent were placed in the same tank with three common carp (either injected or not injected with ovaprim) as inducer with composition ♂♂♀ not injected (A), ♂♂♀ injected (B), ♂♂ injected ♀ not injected (C), ♂♂♂ injected (D), ♂♂♂ not injected (E). The results of this study showed that the inducer on fish spawning by Cangkringan Method is the common carp because the Java carp will spawned only after common carp spawn. In this study, the Java carp did not spawn before the common carp. The Java carp spawning was done to either by a heterosexual common carp (♂♂♀) or monosex (♂♂♂) spermiation. The resutls showed that the fastest spawning of java carp due to stimulation from common carp occurred in D treatment (3 hours 15 minutes) and C treatment (4 hours 17 minutes). Java carp spawnning were obtained 66.7 % for B (K +) treatment, 66.7 % for D, 33.3% for A, 33.3% for C and 0% for E treatment, respectively. Results of hormones analysis showed that the concentration of testosterone in males and estradiol in female common carp after spawing enable to determine spawning status of Java carp. Concentrations of 1.08 to 6.53 ng mL-1 testosterone enable to triger Java carp spawn naturally or to be stripped (treatment B3, C3, D3, A2, B1, and D1). Mean while, too low concentrations (less than 1 ng mL-1) in
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