ABSTRACT-In October 2005, a mass mortality of yolk-sac larvae of yellowfin tuna Thunnus albacares due to an endoparasite infection occurred during the seed production in a semi-closed system tank in Bali, Indonesia. Prevalence of the infection reached 100% maximally. The affected embryo or yolk sac of hatched larvae was filled with numerous parasites by 24 h post spawning. The larvae died due to a burst of the yolk sac. Phylogenetic analysis with 18S rRNA sequence and morphological characteristics of the parasite indicated that the present parasite was identified as a protozoan endoparasite Ichthyodinium chabelardi infecting the yolk-sac larvae of Atlantic sardine Sardina pilchardus or as its closely related species. PCR with a primer set designed from the 18S rRNA sequence detected the genome of the parasite from infected fertilized eggs, yolk-sac larvae and rearing water but not from the gonads of broodstock or feed fish for broodstock. The infection was not observed when the spawned eggs were immediately transferred into sterilized seawater, but the eggs kept in the rearing water for more than 1 h were infected by the parasite. These results suggest that the parasite infects fertilized eggs horizontally through the rearing water.

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Humpback grouper (Cromileptes altivelis) has been successfully spawned in 2000 by IMRAD (Institute of Mariculture Research and Development) and there are already the third generation (F3) currently. The reproductive aspects need to be studied to support the success of seed production. Humpback grouper reared in floating cage (F1 and F3) had matured (gonad stage 4) while F2 fish reared in concrete tanks has spawned. Gonadal maturity stage of 38 fishes from first generation (F1) and 35 fishes from the third generation were observed in June 2013 and compared to gonadal maturity stage of 18 fishes from the second generation observed in June 2009. Samples were measured in total length and body weight and gonads were taken for histology preparation to determine gonadal maturity stage and the sex. From the histological observation of the gonads, it showed that all female humpback grouper were in early maturity stage (stage I and II) with gonadal maturity index between 0.12% and 5.45%. Further, it was observed that the same gonad was found in different maturity stage and concluded that humpback groupers were multiple spawners (asynchronous). By determining gonadal maturity level, it was also known the minimum size for grouper ready to spawn.

<p>One of marine ornamental fishes which was succeeded on its breeding, from eggs production to larval and juvenile rearing at Institute for Mariculture Research and Development, Gondol was Clown fish, <span style="text-decoration: underline;">Amphiprion</span> <span style="text-decoration: underline;">percula</span>. In local name, the fish also known as Biak Clown fish. In culture development, the fish frequently faced the problem on color pattern which was not meet with export demand. The fish should be bright orange and thin black stripe pattern. In this experiment, analysis was conducted to understand the juvenile color variation produced from 3 pairs broodstock. Larvae and juvenile were reared in the indoor hatchery for 2-3 months,then reared at outdoor tanks for other 3-4 months. Amplification of broodstock and juvenile genoms using specific primer for pigment sequens. Parameters observed on juvenile were classified into three color pattern classes i.e., class I (thick black stripe and disperse), class II(thick black stripe), and class III (thin black stripe). Numbers of juvenile analyzed from its pair broodstock and each class were 2-3 fishes. Color perform similarity coefficient was analyzed  molecularly using sequencing. Sequencing process followed: DNA isolation, amplification using   gen Tyr primer, purification PCR product and finally DNA sequencing. Sequencing analyses of PCR product, after alignment  showed that similarity coefficient of color pattern of class I, II, and III between broodstock and juvenile was only 50 %, and phenotipically, color pattern appeared on juvenile were different than its broodstock. The changes of color perform on Clown fish also affected by interaction between genotype and environment and feed pigment concentration.</p><p>Keywords:  heredity, color pattern, Tyr gene, clown fish, A. percula</p>